Interview with Dr. Vladimir Romanovsky, of the Geophysical Institute, University of Alaska, Fairbanks, AK, January, 2009

Summary: CA-CP had the opportunity to interview Dr. Romanovsky, a permafrost and climate change expert of the Geophysical Institute at the University of Alaska, Fairbanks. Dr. Romanovsky discusses his research in the field of permafrost geophysics, history of permafrost, thermokarst lakes, methane and sub-sea permafrost degradation, and his recent trip to Mongolia. Dr. Romanovsky addresses the key technical challenges in his field, the challenges of incorporating permafrost processes into models and explains the implications of crossing regional climatic thresholds. Dr. Romanovsky believes Interior Alaska is just a half a degree Celsius away from crossing such a threshold and, if global warming continues at its current rate, within 20-50 years it could be crossed. This would release large amounts of carbon into the atmosphere irreversibly, causing a positive feedback to climate change.

CA-CP: Dr. Romanovsky, can you explain the scope of your work and research and your interest in this field?

Dr. Romanovsky: I work on permafrost geophysics which means that I study the temperature field of the upper part of the earth's crust and observe the temperatures below 0°C where material is frozen. I study the history of the development of the permafrost, the present state of permafrost, and evaluate possible changes in the future. Of course the most significant agent here is climate because permafrost is a product of a cold climate and if the climate changes then permafrost will follow sooner or later. Our major focus is to see how permafrost reacts to changes in climate. I also study whether changes in permafrost can have some feedback on the climate. This question is as interesting and as important as the direct effect of changes in climate on permafrost. Permafrost geophysicists are also interested in how permafrost changes relate to other components of the Arctic system such as the Arctic ecosystem, vegetation, carbon cycle, and hydrology - how water relates to permafrost. We also study how humans interact with permafrost, how they affect permafrost and how changes in permafrost affect humans. We use geophysical methods to study permafrost and one of the most direct methods is measuring temperature in the upper several tenths to hundredths meters in subsurface. We define permafrost as the ground, the rocks or any earth material (except for glaciers, ice sheets and sea ice) that is below 0°C for two or more years. We look to see if there is any permafrost, and we study its state - whether it's stable or unstable, and we look at its dynamics. We look back as far back as records allow. They don't go too far back but we are trying to establish as many sites as possible to gather data for the future to compare with current observations. This is one big part of our research - measuring the temperature in permafrost in as many places as possible. As geophysicists we use mathematical models to understand why temperatures are changing in the permafrost and to predict what will happen if climate changes. A more recent tool is remote sensing. All of our sites for measurements of permafrost are just spots in a huge area and to do some sort of correlation and interpolation between them we need to use modeling and remote sensing.

CA-CP: Experts talk of climatic thresholds - the point at which it is hard to turn back to previous conditions. How close are we to approaching climatic thresholds with regard to permafrost?

Dr. Romanovsky: When you talk about permafrost, there are some regional thresholds. It would be hard to say there is a global threshold. In terms of regions, for example, in the interior of Alaska, we are very close to this threshold. We are just a half a degree Celsius off of it and in terms of time, it all depends on how climate will warm in the future and the rate of warming. But it could be on the order of 20-50 years.

CA-CP: If you cross this climatic threshold in Alaska, what would the impacts be?

Dr. Romanovsky:What is happening now is that some permafrost is thawing already. It is really a threshold because you can't go back easily and put all this ice that will melt out of permafrost that is water and put it back as massive ground ice. You'd need another glacial period, and in this case it's not reversible. It's hard to put ice back. If the threshold is crossed back to colder conditions it could develop new permafrost but not the same as it is now - generally less ice and less carbon. No return to the previous state. For Siberia and the icy permafrost there, there are two degrees to go before we cross a threshold. So, it is not as much threat yet. However, in southern regions of western Siberia there is a lot of carbon sequestered and the permafrost is actively warming there and thawing in some places. In terms of time scale, I think we could cross a threshold there in several decades. The Northern slope of Alaska is more stable. We maybe have another 70-100 years before we cross a threshold there - same for that area in Siberia. So for colder areas, this threshold is more distant and for warmer permafrost, which has ice and carbon in it, the climatic threshold is pretty close already.

CA-CP: We understand you were just on a trip to study permafrost in Mongolia?

Dr. Romanovsky: Yes, in Mongolia we visited our colleague who is setting up several dozens of permafrost observation sites. We spent 12 days driving from one site to another and covered 3000 km. We measured temperatures in boreholes and installed equipment to help our colleague make these measurements more technically accurate and easier to conduct.

CA-CP: If you look at the density of borehole measurements across the globe is it a fairly even distribution or are there areas of the earth that are better covered for permafrost measurements than others?

Dr. Romanovsky: In general, the research in the high latitudes is challenging and I don't know anywhere where we have good coverage. Most permafrost boreholes are related to other activities because in the past it has been difficult to get funds to study permafrost itself. Deep boreholes are all related to oil and gas research areas, or geological research. When the boreholes are no longer used for these activities, they can be used to measure temperature in permafrost. This is why there is better coverage in the North Slope of Alaska. We have good coverage around Fairbanks, but we don't have good coverage in many other areas. The same goes for other countries. In Russia, there are many boreholes in West Siberia where there are a lot of oil and gas activities - but almost none in central Siberia.

CA-CP: Can you explain the history of all of this permafrost carbon and how the carbon got into the ground?

Dr. Romanovsky: It's very important to understand history to understand what could happen in the future and it's true of permafrost because of possible continuous warming. If you know the age of permafrost - when it was created - then you can have a good idea when it will start to thaw. Younger permafrost is less stable because it was a product of the Little-Ice Age and is thawing now very actively. We are also observing older permafrost from the last several thousand years starting to thaw. If warming continues, we will see the older permafrost developed in the last glacial period start to thaw. History is important for predictions as well. In general, it is important to know how permafrost developed and then you can explain such facts as the carbon source. There are places, especially in Siberia, where permafrost is as old as two million years. But most of the current permafrost was shaped during last glacial period - some time between 20 and 80 thousand years ago. It was much colder then than it is now and permafrost distribution was much wider. Permafrost occupied a significant part of Europe, a very significant part of northern Eurasia, practically all Russia, Mongolia, and northern China. In North America all non-glaciated areas in Canada and Alaska were permafrost areas. Canada had the largest distribution of permafrost - almost all of it was occupied by permafrost. Permafrost existed in some places underneath the huge glacier that covered North America. Remember that the sea level was 120 meters lower so permafrost was forming on all Arctic shelves because conditions were harsh - 10-15 degrees colder than now. A very specific ecosystem developed during this period of time. All of Siberia and Alaska was made up of mammoth steppe or grasses with no trees. Except for some mountain ranges all the land was covered in productive grassland and huge number and variety of big grazers such as mammoths, horses, bison, and caribou. It is important to know that they were there exactly when a significant amount of carbon was sequestered in the sediments. The sedimentation rate was high - mostly wind blown dust but also some aquatic sediments as well. Meters of this new soil could be developed in thousands of years. Because the sedimentation rate was high and productivity of this grass tundra was high, lots of carbon was buried in the soil and frozen in the permafrost almost as soon as it was deposited and since then, in many places in the present day permafrost areas, it's still frozen. In this period of time, a significant amount of carbon was taken out of the atmosphere and deposited/sequestered in an ice complex. An ice complex is a layer of soil/ice, in some places 40-50 meters thick in a frozen state. These exist in East Siberia and in Alaska. Much of the permafrost disappeared after this last glaciation ended, some 15,000 ago. The warmer period of time continues to the present and a very significant portion of the sediments have thawed and the carbon has been released into the atmosphere. We are working on understanding how much was released. There is still a significant amount of carbon sequestered in these types of sediments which have been sequestered for tens of thousands of years. If warming continues, it could be released into the atmosphere on the much shorter timescale.

CA-CP: What causes methane gas hydrates (or clathrates) to form? Is that all anaerobic decomposition or something else?

Dr. Romanovsky: Most of the methane is from natural gas from deeper soils in earth - from the same source that oil comes from. Some of the methane could be biogenic methane but it's a smaller amount. Most of the methane is stored in clathrates. What is a clathrate? It looks like ice. It forms at certain temperature and pressure conditions when you have mix of water and gas and in this case we are talking about methane. It could be carbon dioxide clathrates. All gases can form clathrates. Methane clathrates formed when the gas was present in sediments, buried, and the temperatures went down and pressure rose. Clathrates are a very effective storage mechanism for the methane.

CA-CP: Is it evenly distributed around the areas that have permafrost or are there stronger pockets than others?

Dr. Romanovsky: This is mostly related to the sources of gas and all of these gas and oil provinces in the north have clathrates. There is a strong correlation with petrochemical fields because the source of clathrates is from these fields. But if you look in the north it's everywhere - Alaska, northwest Canada, Norway, Barents, Kara and Laptev Seas, and East Siberian Sea - because all are oil and gas provinces.

CA-CP: There has been recent discussion and study of sub-sea permafrost degradation and of how methane is getting into water columns. Can you explain what is happening?

Dr. Romanovsky: First of all there is a huge need to study this. We have limited data available. What we know based on several scientific projects - some from Canada and Alaska - is that there is a huge amount of methane sequestered in hydrates. We also did some modeling that showed the possibility of release of methane from hydrates, in relation to long-term changes in climate like inter-glacial cycles, one of which we are experiencing right now. What we know now is that during glacial periods, formation of permafrost on the arctic shelf served to block free gas supplied from subsurface gas and oil areas. The permafrost was forming - it was impenetrable and thick and in these favorable conditions, gas and water turn into hydrates. When the last glacial cycle turned into the interglacial all the Arctic shelves were covered with sea water. The temperature at the bottom of the sea on these shelves that had been -15° C to -25° C, during the last glacial period (50,000 years ago) increased to -1.8 °C or warmer. The permafrost started to thaw from both sides - from top down because of the chemistry of salty water, and from the bottom up as the thermal process also affected hydrates as well. The question is, if hydrates decomposed at - say 500 meters - under permafrost still there will the gas can reach the surface of the earth (bottom of ocean) and if so, will it be released in the water, and then into the atmosphere? This has to be further researched but there is some evidence that permafrost is thawing from both sides and there are some methane concentrations in the sea water which exceed by one or two orders of magnitude the equilibrium concentration of methane that we would expect in sea water. This means that there is some source and we see these methane increases not only at the bottom sea water but at the sea surface. It means there is some methane coming into the water and going through the water and probably being released into the atmosphere. It is expensive to do this research, but several expeditions have studied this phenomenon. Given that permafrost on the shelf is warming now at least -2°C or warmer - and given the history of sediments (marine sediments for some period of time, then terrestrial sediment for another period of time, then again marine sediments - because of the glacier/inter-glacial cycles in the hundreds of thousands of years) there could be no ice in the marine salty sediments. Thus, there could be no problems for gas to go through this warm permafrost already thawing, through the tens to hundreds of meters of permafrost if these pathways continue all the way to the ground surface.

CA-CP: Can some of it be released through thermokarst lakes?

Dr. Romanovsky: Yes. We were talking about the sub-sea. Thermkarst is a process that happens on land and its one of the modes of thawing of permafrost. Thermokarst lakes could develop not only in warm thawing permafrost, but also in area where permafrost was thermally very stable. To develop a thermkarst lake, you don't need general degradation of permafrost - you need local degradation which could happen because the summer thaw gets too deep, gets into icy permafrost, and starts to melt this ice. Melting ice creates subsidence, so it's actually a very good example of a positive feedback mechanism. Subsidence will keep water on the surface which will create even warmer conditions and during the winter snow will accumulate in this area and it will get even warmer and so on. You can develop thermokarst lakes in areas where general permafrost is not affected, where it is still -5°C to -8°C. This happened in the past during the Holocene period - an explosion of thermokarst lakes in an area where there was general stability with lakes up to 10-15% of general area. This will release the carbon stored during this previous cold phase when there were no lakes.

CA-CP: Once a thermokarst lake forms, why is it that you get accelerated thaw below it?

Dr. Romanovsky: Imagine the surface of tundra which is flat, snow blowing during winter, not too much snow on the surface, and air temp still cold at -12°C or -10°C annual average. The summer thaw will be only a half a meter deep. For some reason there is a disturbance, with a warming climate, summers get warmer, you get a little bit deeper thaw during summertime. With an increase in summer thaw the upper part of the permafrost which is 70-80% ice starts to thaw and develop a depression on the ground surface with standing water - at first just 5cm on the surface, then 10cm. When you start to get 20cm it's already a pretty good depth in a flat surface of tundra, soon you could have half a meter of this depression which may be several meters or tens of meters across. In tundra, generally there is lots of water because evaporation is low. So then, you start to collect water in this depression, the water on the surface during summer time is an effective way to absorb solar radiation. So albedo and penetration of solar radiation through the water increases the absorption of solar energy in the lakes.

CA-CP: So it's a summer warming effect that forms the thermokarst?

Dr. Romanovsky: Right. There's a summer warming that started this and as it continues and gets warmer, more ice melts until eventually lakes can be 3-4 meters deep. And in this case, permafrost will be continuously thawing because during the wintertime only two meters of ice will form on the lake and another meter or two below will be just water - so the bottom of the lake will always be above 0°C and permafrost will be continuously thawing.

CA-CP: How has modeling of the release of permafrost carbon into the atmosphere, and the potential positive feedback mechanisms progressed? Have the main GCM models incorporated permafrost carbon? Has the IPCC?

Dr. Romanovsky: The processes weren't included in the IPCC. But there are several groups working on this right now. I am working with two of them - one in Colorado, and another in Potsdam, Germany. They are trying to incorporate the effect of thawing permafrost and the effect of the possible release of carbon. We want to include this in a model and let it run to see how much carbon will be released into the atmosphere. It's a difficult task because we are adding several components that weren't in GCM models before like permafrost dynamics and the sequestration and release of carbon. To include this is a significant improvement. But it is difficult to do the biological components of models, and to put it together to couple them. It is a really big task and I don't know when it will be completed.

CA-CP: We understand that you work in several areas such as hydrology, ecosystem, and vegetation. In these areas and from all of your work, what impacts of permafrost thawing have you been observing in Alaska?

Dr. Romanovsky: In terms of hydrology, it's a combination of factors. We already see it. Thawing permafrost will affect hydrology and lower laying areas. The thawing of permafrost is already creating different soil moisture conditions - more bogs growing, more wetlands in some areas while the well drained areas are drying. There have been studies on the stress on tree vegetation in Alaska due to this drying. This could be related to changes in permafrost - a lower water level creating drier conditions, could lead to losing forests to grasslands. This is actually happening in Mongolia. On my trip, it was amazing to see that in the some areas where marginal permafrost exists, the large trees grow only where permafrost exists. Where it does not, it is too dry for trees. The changing permafrost is already affecting infrastructure. This is complicated because most engineering structures built on permafrost have a significant effect on it. In general, with warming climate, permafrost is getting warmer and more vulnerable. The stability found in colder permafrost will be lost in warmer permafrost. While there are not huge difficulties with the pipeline, they are constantly working to support integrity of it, much more work than 20 years ago because it is much warmer. In many places, permafrost is disappearing from surrounding areas and only exists under the thermopiles - the design they used to maintain frozen ground. It is unclear how long they can maintain this stability.

CA-CP: Are you aware of new ideas to slow the thawing of the permafrost? Technical or involving R&D?

Dr. Romanovsky: There could be local solutions - pure engineering to freeze, but they are all expensive. And these engineering solutions cannot be easily used for linear structures like roads, railroads, or runways for airports. So engineers are able to keep infrastructure safe, but it's becoming more and more expensive. The general solution can be only to keep the status quo of climate by limiting emissions from human activities. It is difficult to control the natural release of gases from permafrost so it is better to not let permafrost thaw.

CA-CP: The community that's doing permafrost research seems small but a tight international group. As a whole, is the research being funded at a reasonable level? Are people able to make the progress they need to make?

Dr. Romanovsky: In different countries the situations are different - you're right it's small but tight. We have good leaders, like Jerry Brown of the International Permafrost Association. Norway has good funding. The US is actually getting much better. Ten to fifteen years ago it was hard to get funds. Now it is not ideal, but better. We are trying to sustain long-term observation projects that last 3-5 years. This is a long-term changing creature and we need long-term data to understand what is going on.

CA-CP: What are the key technical challenges that the scientific community need to address?

Dr. Romanovsky: We are still working with data points that are sparsely distributed over the permafrost area. It is a major challenge to find how best to interpolate and extrapolate data to the entire area of permafrost distribution. There is some possibility of remote sensing but it is difficult. There is no direct way to measure permafrost from space.

CA-CP: What are the parameters of remote sensing?

Dr. Romanovsky: It is challenging because all of the information you can capture using remote sensing is from a shallow surface layer. But, the combination of remote sensing, ground measurements and numerical modeling can help. For example, it is possible to measure surface temperature but still not precisely - at least within a degree.

CA-CP: How does the warming of the ocean in general affect the rate of permafrost thaw?

Dr. Romanovsky: In many ways. Changes in sea ice cover are of course related to warming in water as well, and directly affect sub-sea permafrost making the rate of degradation much higher. It increases the temperature and probably water content in the atmosphere that goes over land. It creates a warmer summer and fall with increased precipitation. This will lead to warming in the permafrost and have a direct affect on sub-sea permafrost. Now temperatures in deep waters that were below 0°C are sometimes above it. The water is not that deep, and the absence of summer sea ice makes mixing more effective.

Visit Dr. Romanovsky's web pages at the University of Alaska Fairbanks (UAF) and the Geophysical Institute Permafrost Laboratory (GIPL)

Learn more about Dr. Romanovsky's work by viewing his presentation on changes in permafrost and the carbon budget at the American Meteorological Society's Environmental Science Seminar Series (ESSS)

Learn more about thermokarsts here

Read Dr. Romanovsky's essay on NOAA's website.

October 2008 Interview with Clean Air - Cool Planet's Chief Scientist, Cameron Wake. Dr. Wake is a paleoclimatologist and Research Associate Professor at the Climate Change Research Center of the University of New Hampshire.

CA-CP: Why are ice cores so important?

Dr. Wake: Climate scientists love ice cores because they hold really high resolution records of how and why our climate has changed. The ice of glaciers starts as snow, and that snow forms around particles in the atmosphere, and that snow accumulates on glaciers. Depending on the location of the glacier, this results in several feet of snow per year - with less in Antarctica and more in Greenland, for example. This annual accumulation of snow allows us to count back annual layers hundreds to thousands to tens of thousands of years and they allow us to observe changes in climate that happen very quickly, at least in geophysical terms. So this is why we say they are "high resolution" because they provide annual or decadal records.

CA-CP: What kinds of things can ice cores tell us?

Dr. Wake: There is a large number of analyses we can do that provide information on many different aspects of the climate system like temperature, atmospheric circulation, and dust loading and greenhouse gas content of the atmosphere. So, we can analyze the stable isotope content of the water that comes from the snow, and that provides information on the temperature at which the snow formed and also where the moisture came from, which in turn tells us something about the circulation of air and ocean currents. We can look at the salt, calcium, magnesium, potassium and ammonia, and they all tell us different things about the strength of atmospheric circulation, the amount of dust in the air and the and extent and activity of different large ecosystems. When we look at trace metals, like lead, for instance, that gives an indication of how humans are changing the environment over time. There are also air bubbles trapped in the glacial ice containing greenhouse gases, like carbon dioxide, methane, and nitrogen oxide. From this we can track the variability of greenhouse gases over time, and compare this to changes in temperature and atmospheric circulation. There is also dust from desert regions and volcanoes deposited on the glacier. How much there is and where it comes from and how it changes over time tells us about atmospheric circulation (both air currents and ocean currents), how desert regions of the globe have changed, and when volcanic eruptions have occurred in the past. For example, ice core data shows strong correlations between deposition of iron dust on the ice sheets and a decrease in the carbon dioxide content of the atmosphere. This suggests that increased iron deposition in the oceans (inferred from increased deposition on glaciers) is an important mechanism regulating how much carbon dioxide is removed from the surface ocean by phytoplankton in the oceans, since phytoplankton populations are increased by iron. Finally we can look at certain isotopes in the ice that represent records of solar activity. By comparing these with other analyses, we can get a picture of how the sun influences climate as well.

CA-CP: When you put all this together, what does it tell you?

Dr. Wake: We refer to the ice cores as a source of multi parameter information, and we first try to describe how climate has changed. Then, when we've determined how it has changed, we can use the information from these cores, and other sources of information, to help us determine why it has changed.

CA-CP: What is the reason for collecting core samples in so many remote places around the world?

Dr. Wake: Remote areas have no local sources of pollution, so they are useful in generating a true record on a broad scale, from regional to hemispheric. But we need to have cores from multiple locations in order to better understand the regional variability in the global climate system. From large ice sheets like West Antarctica and Greenland, we have very long global records, while from mountain glaciers we have regional pieces, and we can investigate regional similarities and differences. The data that originates from ice core records is also used to verify output from global climate models. Finally, ice core records from around the globe have provided valuable information on rapid climate change events (dramatic changes in climate that occur in a decades or less). Ice cores, because of the annual resolution, can add that kind of detail of changes over more refined time scales.

CA-CP: You were working on an ice core project in Denali National Park (home of Denali a.k.a. Mount McKinley, the highest peak in North America at 20,320 feet) this summer. Why?

Dr. Wake: One of our goals is to develop a more comprehensive understanding of how climate has changed throughout the Arctic. In order to do this most effectively, we are gathering the high-resolution, multiparameter records of ice cores from various ice caps and glaciers around the region. We have the long-term, hemispheric record from Greenland, and now we are compiling records from a network of other locations in order to better understand variations in sea ice, volcanism, pollution, and the regional characteristics of climate events like the Medieval Warm Period and the Little Ice Age. This network includes the Penny, Devon and Agassiz ice caps, glacier ice on Mt. Logan, and the Eclipse Icefield. Other groups are working in Scandinavia at Spitsbergen and Svalbard, and in northern Russia. We had records from coastal Alaska, but none from the interior, and our work in Denali will help fill that gap. A clear record from Denali will help round out the bigger paleoclimate picture by adding critical information gathered from ice cores recovered around the North Pacific, all of which can be compared to a wealth of climate data already gathered in the North Atlantic region. One of the particularly interesting and challenging pieces of this project is testing a long-standing hypothesis that the North Atlantic region drives global climate changes. But there are now indications that a change in the North Pacific might happen first and drive a North Atlantic response. We need to better understand the relationship in terms of the timing and magnitude of climate change between these two regions if we are going to really understand what drives climate change in the Arctic. And so developing these high-resolution records that are directly comparable is really important.

CA-CP: What do you hope those comparisons will tell us?

Dr. Wake: There are some really big questions to answer about the timing of climatic events, which is absolutely necessary to understanding the why climate changes question. We think that 1500 year cycles are driven by deep water circulation in the North Atlantic - so changes should appear first in the North Atlantic and then in Antarctica, where long records do not have the resolution of the shorter records we are getting here. Ice cores currently being recovered from the West Antarctic Ice Sheet will be compared with data from Greenland to help unravel timing, and then data from the tropics, from the Andes, for instance, will tell us about when changes occurred there. The data we will get from Alaska will help to explain what is going on in the North Pacific and when. Ultimately, we are trying to put together the puzzle of the global climate system - what are its drivers, what makes things happen, and why.

CA-CP: What did you accomplish this summer?

Dr. Wake: We started out this summer using a portable, ground-penetrating radar to determine the ice thickness and internal structure on various glaciers, looking for "layer-cake" ice with clear, well-defined annual strata. We also collected samples for chemical analysis from 20-foot-deep snowpits and firn (snow that has not turned to ice) cores drilled 60 feet deep from the bottom of the snowpits, and installed automatic weather stations at heights of 7,800 and 14,000 feet. The chemical analyses will be carried out at UMaine and UNH labs to decipher changes in temperature, atmospheric circulation, and environmental change - such as the phenomenon known as "Arctic haze," which has brought heavily polluted air masses to the region for decades from North America, Europe, and Asia. We expect to spend one more field season at Denali next year - to download data from the weather stations - and then hope to begin the deep-drilling program in the spring of 2010, if we get NSF funding for the second phase of the project. Our goal is to recover surface-to-bedrock ice cores from glacial ice that is about 1,000 feet thick, which should provide a detailed record of climate and environmental change extending back several thousand years.

CA-CP: Where does all of this fit in the huge picture of the climate of the planet?

Dr. Wake: It's a tiny piece, 800,000 years out of roughly 4.5 billion - but it's the most recent piece. The farther back you go, the less we know. What we know about the distant past is from geological deposits, sediments, and glacial deposits - rocks. And rocks can't tell us things with the resolution and subtlety of snow. On the other hand, we discovered most of what we know about the occurrence and reoccurrence of ice ages from studying glacial moraines. Some of what we know comes from our understanding of how changes in our orbit of the sun, combined with sometimes very small changes on the planet, magnified by feedback loops, can drive huge swings in the Earth's climate. So, what starts a change may be very small - like the hole in the tire that eventually stops the car. If you look at what's happening now with sea ice, for instance, and the loss of albedo or reflectivity and more and more heat-absorbing dark water being exposed, warming, and melting more ice, you get a sense of how something that starts out small can be magnified by a positive feedback. But we have a good understanding right now of a lot of the parameters - the water, air, and temperature, and how it's changed at least in the last at least half million years. Now we're working hard on the why.

In October of 2008 CA-CP interviewed Dr. Epstein, Associate Professor of the Department of Environmental Sciences, University of Virginia. Dr. Epstein is a tundra ecosystem ecologist who studies climate-plant-soil interactions in Arctic environments.

CA-CP: Dr. Epstein, your recent research has involved measuring the amount of soil organic carbon in the North American Arctic region. Can you explain why it is important to understand how much carbon is stored in the tundra of the Arctic and how it relates to climate change? How could it affect people living in lower-latitudes?

Dr. Epstein: It is important to understand the quantity of organic carbon (C) stored in permafrost regions, because it is such a huge pool of carbon, and therefore relatively small changes to this pool can result in large environmental impacts. Schuur et al. (2008) estimate that the total organic carbon stored in areas that have permafrost to a depth of 3 meters is 1024 Gigatonnes of carbon (1 Gt = 10^15 grams); the amount of carbon presently in our atmosphere is approximately 750 Gt, so this is ~36% more carbon than the total in our atmosphere. For just the arctic tundra biome (which is about one-fourth the size of the entire permafrost region), a circumpolar extrapolation from Ping et al. (2008) yields ~160 GtC to a depth of 1 meter, still a sizable amount.

This carbon is essentially old, dead organic matter from plants and other organisms that has not decomposed due to cold or frozen soils, and saturated soil conditions in certain areas of the tundra. Much of this carbon developed in place due to vegetation growth and subsequent death. However, substantial quantities of carbon were also deposited in windblown sediments during glacial periods onto unglaciated areas of the high latitudes. This organic carbon is converted to, and released as, carbon dioxide during decomposition by of the organic material by micro-organisms. Warming of tundra and permafrost-dominated soils would increase the rate at which this organic matter is decomposed and converted to carbon dioxide. Any thawing of permafrost would expose new, previously-frozen, organic matter for decomposition. Many areas of the tundra are wet, and decomposition is limited by saturated soil conditions. One possible outcome of warming is drier tundra soils, which could enhance decomposition and carbon dioxide production in wet areas. This may also reduce decomposition in areas that already somewhat dry.

Schuur et al. (2008) cite a few estimates of carbon release due to thawing permafrost in the range of 50-100 GtC over the next century. This of course has implications for low latitudes because carbon dioxide is rather well-mixed in our atmosphere. A rough conversion suggests an additional 25-50 ppm carbon dioxide in the atmosphere from permafrost soils; we are presently at ~382 ppm.

CA-CP: How has this latest research built upon the previous understanding of the amount of carbon in Arctic tundra?

Dr. Epstein: The most commonly cited numbers for soil organic carbon in northern regions come from a paper published in 1982 (Post et al.). They estimated 21.8 kg of soil organic carbon (SOC) per square meter. The Ping et al. (2008) study found an average of 34.8 kg SOC per square meter to one meter depth, an increase of almost 60% over the prior estimates, with 38% of the carbon found in the permafrost. Schuur et al. (2008) extend the estimates to the entire permafrost region, which is approximately 3-4 times the size of the arctic tundra biome.

CA-CP: Can you explain cryoturbation and how it affects carbon in the tundra?

Dr. Epstein: Cryoturbation is a disturbance associated with the freezing and thawing of soils. In the winter, tundra soils freeze and expand, and in the summer they thaw and settle. In some locations of the tundra this freezing and thawing is relatively homogeneous, and soils expand a few centimeters in the winter as the liquid water changes to the less dense ice. However, in other locations, depending on local conditions (importantly, soil texture, soil moisture levels, and rates of freezing), some areas may expand to a greater extent than others, even 10-20 cm (known as differential frost heave). The processes of cryoturbation and soil expansion, particularly in places with differential frost heave, can move organic carbon from the surface to greater depths in the soil, possibly even being ultimately frozen in the permafrost (Michaelson et al. 1996; Walker et al. 2004, 2008; Bockheim 2007). Cryoturbation can therefore enhance the sequestering of carbon in tundra soils, by moving it from the exposed surface to deep in the soil profile and potentially in the permafrost.

CA-CP: What is the role of Arctic tundra vegetation in all of this? How could it develop and how would it affect the dynamics of the region? What is the role of photosynthesis and increased vegetation?

Dr. Epstein: Arctic tundra vegetation of course plays a crucial part in the arctic carbon cycle. Growing vegetation during the summers sequesters carbon from the atmosphere in the process of photosynthesis. This carbon is temporarily stored in the vegetation, but may ultimately end up in the soil organic carbon after either just certain plant parts (e.g. deciduous leaves) or the entire plant dies. A warming Arctic is likely to lead to increased vegetation with increased photosynthesis and carbon dioxide uptake from the atmosphere. There is already evidence of increasing vegetation from a number of studies (e.g. Sturm et al. 2001, Jia et al. 2003, Goetz et al. 2005, Tape 2006). The tundra vegetation has other important functions - one is to insulate the soils from variable air temperatures. Soils in a highly vegetation location will be warmer during the winter and colder during the summer than soils, for example, with out vegetation. So the presence and quantity of vegetation and its insulative properties has an effect on soil temperatures which in turn affects micro-organism activity, decomposition of soil organic carbon, and carbon dioxide release to the atmosphere.

A major unknown is how the arctic carbon budget will change in response to a changing environment, given that certain processes lead to greater sequestration of carbon in soils, whereas others will lead to increased release of carbon from soils.

View the projects Dr. Epstein is involved in: Greening of the Arctic, The North American Arctic Transect, and Biocomplexity of Arctic Tundra Ecosystems

Visit Dr. Epstein's home page at the University of Virginia to view a list of his recent publications.

View Dr. Epstein's presentation on the New Estimates of Carbon Stores in Arctic Tundra and Permafrost Soils given at the American Meteorological Society's Environmental Science Seminar Series

In September of 2008, CA-CP had the opportunity to speak with Dr. Konrad Steffen, Director of the Cooperative Institute for Research in Environmental Sciences (CIRES), at the University of Colorado. He described his extensive research on the Greenland Ice Sheet since his Swiss Camp was built in 1990 which he has corroborated with satellite observations collected since 1979. He explained how the ice mass of Greenland is decreasing, especially around the edges. In addition to melt water flowing directly to the ocean, melt water collects on the top of the sheet and works its way down through tunnels to the base of the ice sheet accelerating ice flow to the oceans causing icebergs to break off. Dr. Steffen anticipates sea levels to rise by 1-1.5 meters by 2100 given current conditions. The interview below delves into his important work.

CA-CP: Can you tell us about your current research efforts and how long you have been working in Greenland?

Dr. Steffen: I started working on the Greenland Ice Sheet in 1990 when we put up a camp, now called Swiss Camp, about 70°C north on the western slope of ice sheet. It was a pure science camp in 1990. The idea was originally to study interaction of the climate and the ice sheet itself. We built a 30-meter tower to study the boundary layer of the atmosphere and worked locally around the camp to study the processes of energy transfer from the atmosphere into the ice. We also studied precipitation and the turnover of the energy involved in melt and evaporation. We did not anticipate the climate change study. Then after two years, there was a big volcanic explosion in Mt. Pinatubo that cooled the climate in the northern hemisphere by 1.5°C - mainly in the Arctic. That was the year without summer. We had no melt at that station which is 1100 meters above sea-level and we continuously had snow. Since the station was under so much snow, it could not be moved out and the opportunity arrived to buy the station with NASA for $1. Since this purchase, I have gotten continual research funding from NASA to use this station and other stations built later to continue basic research for climate, using satellites to collaborate.

CA-CP: Can you explain more about this work with NASA?

Dr. Steffen: After 1990, we worked about three years, and then we started the big program in NASA, called the Program for Arctic Regional Climate Assessment- PARCA. NSF joined in the later years and we started to put up climate stations on the ice sheet to find out if the Greenland ice sheet is balanced, which means if the precipitation that falls on the ice sheet is equal to the surface melt that runs off and the icebergs that break off. It's hard to believe, but in 1990 we did not know yet if Greenland was gaining mass or losing mass. And the stations we put up - we have 22 -record the precipitation, melt, and surface height change; that was one part of the PARCA program. We collected ice cores funded by NSF, which looked at the past history of the ice sheet. The shallow ice cores of 100 meters in depth provide a climate history of up to 800 years By 2000, eight different universities collaborated under the PARCA umbrella to do climate research on the ice sheet. That's how it started. We just received more funding from NASA that continues research for next 3-4 years to use the climate stations and satellites and process studies on ice sheets to understand the mass exchange of the ice sheet. A good example is a new Ice, Cloud, and land Elevation Satellite, also called ICESat. This is the first satellite built for crysopheric research to measure the change of the global cryospheric ice. ICESat has a laser that measures surface height very accurately and changes can be derived from one orbit to the next over the same region. Changes in height are not only caused by changes in precipitation or melt but also by the variability of the temperature within the surface snow. To understand the effects of a warming climate, we need to have a good combination of field measurements and small-scale in-situ process studies that we then use to correlate with satellite geophysical data. The stations have become very valuable because we didn't have any long-term record of the ice sheet. By now, we have 17 years of data for most stations. This data shows us that the climate is changing. With a long-term record, you realize that the temperature in the summer months has increased since 1990 by about 2°C, which is a really large signal. Because most of the time, here in mid-latitude, temperature change is only a fraction of a degree centigrade over that time period. That's why the Arctic becomes important. The temperature changes further north are enhanced which means we see a much bigger signal that has to do the albedo feedback. Albedo is the reflection of the sun on the earth's surface. When you have snow cover, about 90% of the solar energy that goes through the atmosphere is reflected back into space. If you have portions of the snow cover getting wet, which is now occurring at higher elevations of the ice sheet, only about 70% is reflected back into space, and if you go further, and more water is added, which is occurring with the increase in temperature, and you expose some blue ice in the lower regions of the ice sheet, then only 50% of the sun's energy is reflected back into space. That positive feedback increases the temperature and the melt. That occurred from 1990 to present. Actually we do have data from 1979 to the present from NASA satellites that use passive microwaves to measure the Earth surface at least twice daily. We use that satellite data to calculate the melt extent of the ice sheet. We now have an image that shows how many square kilometers of ice are melting on the ice from 1979 to present.

CA-CP: What is the trend that you see when you go back to 1979?

Dr. Steffen: We discovered, already in late 1990s, that there had been a strong increase in ice sheet melt extent. The increase is not linear; we had a variability of 2-3 years with a new maximum in melt extent. Over the time period 1979 to present, the area that melted on the ice - when you add up the summer melt - has increased by 30%. This indicates that the summer air temperatures are rising. Increased warmth enables the snow to melt at higher elevation - the Greenland ice sheet ranges from sea level to 10,000 feet (3300 meters). Only the margins of the ice sheet are actually melting, but this melt region is moving uphill towards the center and the total area has increased by 30% - not as a steady increase, but every 2-3 years, a larger area. The year 2007 was our last maximum and that was a 10% larger melt area than any year from 1979 until that time. It's interesting to see that it's not only the summer temperatures that increase - the biggest increase is actually in the winter months. But winter is still very cold so the temperature is below freezing. For the time period 1990 to present we had about a 4.5°C temperature increase at the one station we call Swiss Camp, which is 70° north, western slope, 1,100 meters above sea level, close to the town Ilulissat, also known as Jakobshavn in the old days.

CA-CP: How important is Greenland to the world's climate? What are the risks to the expected continuing warming?

Dr. Steffen: Greenland is like a big barrier. It is about 3300 meters high; it runs north-south - 65° north to 80° north. We know that the weather machine for Europe starts in the US - the cyclones that spin off the northern parts of the US cross the Atlantic and cyclones moving across the Atlantic are a driver for the weather in Europe. In the winter Greenland is very cold and it's so cold that these cyclones can't cross the ice sheet. Cold air is heavier so cyclones bounce off at the southern tip of Greenland and cross over Iceland. They are usually called Icelandic lows in Europe. If the climate is altered over the ice sheet in Greenland, this will affect the weather pattern in the northern hemisphere. More important, however, is when you consider how much ice is stored in Greenland. If we were to take all the ice on Greenland and dump it in the ocean one way or the other - melt or ice dynamics - (this will not happen for decades) it would raise the sea level globally by 7 meters. This is one of the bigger issues - to understand better how quickly Greenland will melt in a warmer climate. The IPCC, the International Panel on Climate Change, came out with a report last year and it indicated that by 2100, sea level will rise by up to 53 cm. This is based on the current melt rate of the glaciers, of the ice sheet (mainly Greenland), and of the thermal expansion of the ocean. If you warm the ocean, the ocean has a bigger volume, so 50% of the sea level rise is from the ocean expansion. The IPCC analysis does not include what we call the dynamic response of the ice. In 1995 we realized that the ice sheets are moving faster towards the ocean during the summer months with additional melt. We used instrumental evidence to verify this process. We found that melt water runs by gravity towards the coast and then into the ocean. The melt water runs not on the surface but finds its way into the ice through cracks or through moulins. A Moulin is a large vertical tunnel where the melt water cascades down. That water finds its way to the bottom of the ice sheet, since water is heavier than ice, it can act as lubrication underneath the ice sheet. During the recent summers we measured more surface runoff from melt and also ice that is moving faster towards the coast, indicating that the melt water reaches underneath the ice sheet acts as a lubricant or reduces the friction and advances the ice motion. It flows faster towards the coast and causes more icebergs to break off. It's our current understanding that 50% of ice loss in Greenland is due to melt and the other 50% is due to icebergs that break off from large floating ice tongues into the ocean. A gravity experiment satellite called GRACE measures the total ice loss. Results from the GRACE satellite reveal that Greenland ice is currently losing on the order of 150 - 200 cubic kilometers of ice annually. That is about 1 - 1.5 times all the ice we have in the European Alps. Since the satellite was launched in 2002, there exists a good record about of mass change. The mass loss of the ice sheet has increased every year, and in 2007 it was 200 cubic kilometer or 200 gigatonnes of ice loss, which is an imbalance. This means we lose more ice into the ocean than falls by precipitation. And that is the big question - how can we model that? IPCC did not have this number in their prediction by 2100. We actually were able to put some remarks into the IPCC report which states that the 50 cm sea level rise by 2100 is due to the melt, but if you take into consideration the dynamic response of the ice, sea level rise might be much higher. The big question now is how much higher would it be? It's very hard to give a prediction because we are currently working to model this faster ice flow but it actually takes years - 3-4 years - to get a model working which can predict the future based on the ice flow. We do know that we have a considerable loss of ice mass right now and we believe the 50 cm sea level increase by 2100 is too low because we already see now that the ice is moving faster. There is ice loss in Antarctica as well that was not considered in the IPCC report, that is of similar order, 100-150 cubic kilometers ice loss annually. It could well be possible that we have one meter or more of sea level rise by 2100 and even larger sea level rises in the years after 2100. Most of the model prediction go only to 2100 but sea level will continue to rise for centuries The temperature will continue to increase even if you reduce greenhouse gases today, and the ice loss will continue, too. I don't think we can lose the Greenland ice sheet in a short time. Seven meter sea level rise is not something we will experience in next several 100 to 1000 years. But it's well possible we'll have up to one meter of sea level rise due to the thermal expansion, due the ice mass in Greenland and Antarctica and we shouldn't forget all the glaciers - mid-latitude glaciers are actually melting the fastest right now. If all the glaciers of the earth would melt - except the ice sheet - sea level would rise only by half a meter. So this means the big uncertainties are coming from the Greenland ice sheet and from Antarctica.

CA-CP: You said the melt rates are higher than anticipated when you wrote the IPCC report?

Dr. Steffen: It's not the melt rate; it's actually the ice loss by ice motion that is not in any model. Satellite measurement from GRACE shows that we are losing 100-150 Gtons of ice yearly. We cannot explain that by melt because that would use way more energy than we have available right now at these latitudes.

CA-CP: What does the climate history - studies of paleoclimatic history - suggest about what has happened to the Greenland ice sheet in the past?

Dr. Steffen: We have some evidence from the ice cores. A US paleo-climate research group showed that during the last interglacial period (that is the warm period between ice ages) about 140,000 years ago, the climate was about 4°C warmer in Greenland than today. By that time, Greenland actually lost ice to cause about 1-2 meters of sea level rise. It took several centuries then to reach that warmer climate. Today we predict about the same amount of warming in less than 100 years in that region due to greenhouse gas feedbacks. However, I would not expect a two meter sea level rise from Greenland that by 2100 because it takes centuries to remove that much ice just by melt. The scientific community needs to understand ice sheet dynamics better to predict sea level rise accurately. We believe that half a meter is the guaranteed low end and it is possible we could have 1.5 meters of sea level rise. It took several hundred to thousand years to get a 4°C increase in warming during the last interglacial period and it is likely we will do this in only 100 years now.

CA-CP: You mentioned that in 2007 the melt rate around the edges reached the highest level ever?

Dr. Steffen: Since we only have satellite measurements from 1979-present, we don't know what it was like in the 1930s. In the 1920s and 30s, we had temperatures similar to today, but it took several decades and then got cooler again, which was one of the normal climate variabilities. We are past that point already - warmer now than in the 1930's but we have no data from the ice sheet from the 1930s or 20s.

CA-CP: 2007 was also the year of the greatest extent of sea ice loss in the Arctic and 2008 is close. Is there something to be said that both of these things are happening at the same time?

Dr. Steffen: There is a connection. We have looked into that question for several years now; the cryosphere of the Arctic is all connected together. As a good example, if sea ice coverage in the Arctic Ocean is reduced then more of the dark ocean surface is exposed absorbing more energy and warming the surface water layer. . The ocean has a long-term memory, and if you warm up the ocean temperature, that has an effect on the ice sheet. Ocean water travels as currents under the floating ice and melts the ice from underneath, reducing ice mass. It is not the major part of the ice melt yet it will have an effect. For example - if we lose all that summer Arctic ice in the Arctic Ocean in 10-30 years, that will give us a very large area of dark surface, evaporation of ocean water into the atmosphere, bringing different circulation and that affects precipitation and melt region. It is interesting to note that during the time we had the very low sea-ice extent, we had increased melt areas in the north of Greenland. So there is a direct link - less sea ice, warmer air temperature, more melt of the ice sheet. It takes a while to warm a large portion of the ocean because there are ocean currents that transport energy away - so in the longer term, yes, there will be an ocean warming. It was the ocean that reduced ice thickness, made ice weaker, and that's why it was breaking in part and reduced the area. We still don't know the ice thickness in the Arctic very well. None of the satellites can estimate how thick the ice flows are. We do know that we lost multi-year ice - ice that survives the winter. That is ice that has very little salinity. Ice loses its salt content over a multi-year period and is much more rigid - meaning it will survive several years. We have less and less of that ice type which gives us the indication ice is getting less thick, but that is actually an estimate; we have not very good data.

CA-CP: Here at CA-CP we believe that you can reduce radiative forcing with the reduction of short lived gases (methane, troposhperic ozone, and black carbon) that could produce a quick result and you also need to work hard on the longer-term carbon dioxide reductions. There is a school of thought that at this point you have to consider geo-engineering schemes like reflectors on the Arctic Ocean or sulfates in the stratosphere. Do you have an opinion?

Dr. Steffen: I'm not a very big supporter of geo-engineering. By putting too much CO2 into the atmosphere, we have made a geo-engineering experiment that went wrong. It is very hard to get CO2 out of the atmosphere. There are a lot of mechanisms we don't fully understand. Geo-engineering at that scale, like increasing cloud cover over the ocean, could reduce the incoming short radiation but how well do we know the side-effects? Do we increase precipitation? Flooding in other areas? If you have mirrors in space that reflect energy out into space - what happens if there were several volcanic eruptions cooling the climate by several degrees? The volcanic eruptions are very powerful by reducing the amount of solar energy coming to the earth. If we put reflectors into space, you cannot remove them over night. They come down by gravity and it might take a decade, so we might actually enter a cold phase on earth by having a geo-engineering and a natural cooling. Therefore I think it's quite dangerous to go for these big programs for a short-term fix. The long-term fix is to reduce greenhouse gases and start now because as it takes up to 400 years for the CO2 to be absorbed in the ocean, to be taken out of the system. Whatever we do now, we should start working at the base of the problem. We should discuss geo-engineering, but additional and careful studies are needed first before we enter such a large project of reducing solar energy reaching earth because if it goes wrong, it can go badly wrong.

CA-CP: Are there any tipping points we should be worrying about? Are there any things associated with Greenland that once we go beyond a certain point, if we cool the atmosphere back down, we don't get back to where we are now?

Dr. Steffen: We try to learn from the past history, but the data is usually not that accurate. Tipping point is a good example. Tipping point would mean that we understand the process so well that we can predict when it is going into a different phase. I personally don't think we know when a tipping point would occur. Some researchers mention a tipping point - if you add 500 parts per million (ppm) carbon dioxide into the atmosphere, there is no returning back to the current system. I personally think we don't know the system that well that we can discuss tipping points because there are all the feedback mechanisms we don't understand right now. If you have 450 or 550 ppm in the atmosphere, I would be cautious to use it as a point of no return because most of the climate responses are not linear. There are so many feedback mechanisms, we don't even understand the ocean systems that well. We already have indication that part of the ocean is saturated with carbon. If this is the case, the tipping point is very close. If there is no equilibrium at 550, the tipping point is further away. That's why I am hesitant to give you a direct answer - whether it will be in twenty or five years.

CA-CP: Based on where Greenland is going and the loss of ice mass, what is your best estimate on how much sea level rise we'll have by 2100?

Dr. Steffen: Estimates for conditions in 2100 have different components. Thermal expansion will increase. Greenland's ice sheet is certainly reacting now. The biggest sea level rise currently from the cryosphere is coming form the glaciers - about 50% of the crysopheric contribution. But we actually know how much ice is left in the mid-latitude glaciers -enough to raise sea level by half a meter. Before and by 2100 maybe 2/3 of glaciers on earth will have melted away. Greenland is hard to predict. It's not only melt (we can model that with temperature increase). The dynamic part is not well understood. Will it continue at its current rate with the ice flowing faster, or will there be an upper velocity with no additional increase? I would predict an upper limit of sea level in the order of 1 - 1.5 meters by 2100 due to thermal expansion, and ice loss from Antarctic, Greenland and the glaciers.

CA-CP: We've read that the rate of the ice flow was slower than we'd thought a year ago.

Dr. Steffen: There was a study that looked at radar data and rightly they assessed the increase in velocity is only during the summer months. This is correct and if you take the amount of ice that increases the velocity and add as sea level rise, this is not the major part - I agree with that assessment. But, what we observe is that a lot of outlet glaciers start to accelerate into the ocean. It is not the lubricated ice sheet that makes the big change. The outlet glaciers are flowing faster. For example, Jakobshavn Isbrae, the fastest flowing glacier on earth, was flowing in 2000 at 7.5 km/year into the ocean. Right now it is flowing 14 km/year into the ocean. We think it is triggered by the lubrication at higher elevations which pushes the ice towards the fjord areas and they accelerate down. Outlet glaciers contribute more to ice loss, and if you double the speed you lose much more ice than this 10-30% increase in velocity over a few weeks in the summer.In conclusion, most climate issues are long-term and we need to make changes now to get future sea level rise under control. Most predictions end at 2100 which is two generations down the road, and we do hope we have an earth that is livable by 2300 or 2500. Given the current rate of increase in carbon dioxide output, I'm afraid it will be hard to curb that sea level rise in the near future, which has a marked impact on generations to come. We know that about 150 million people are living within one meter of sea level rise, currently. By 2100 to move that many people away from the coastline will be difficult. We know that 1/3 of the population on earth lives close to the coast and that is the area that grows the fastest - the whole economics there has to change in the decades to come to have a secure life on earth.

Learn more about Dr. Steffen's work at the Steffen Research Group web page of CIRES

Interview with Dr. Mads C. Forchhammer, National Environmental Research Institute, University of Aarhus, Denmark. August, 2008.

CA-CP: Could you tell us about your position at the University of Aarhus and the nature of your research?

Dr. Forchhammer: I am a professor in Global Change Biology at the National Environmental Research Institute, University of Aarhus, Denmark. During the last 15 years, my research has focused on how climatic changes affect the lives of species and the environment in which they are embedded. With my background as a population biologist, I study the effects of climate through statistical analyses and modelling of large time series and monitoring data sets. Since 1996, I've been involved in the large monitoring programme Zackenberg Ecological Research Operations (ZERO), which continuously, year after year monitor climate-related changes in an entire high-arctic ecosystem. The programme involves scientists from the entire spectrum of natural science, climatologists, glaciologists, geo-physicists and biologists. ZERO covers all the terrestrial, freshwater and marine compartments of the ecosystem. You can find more information here. We have recently published a book based on 10 years of monitoring and research at Zackenberg.

CA-CP: How are terrestrial ecosystems changing in the Arctic in response to Arctic Warming? Why is this important to understand?

Dr. Forchhammer: The Arctic may be regarded as a "magnifying glass" for understanding the effects of climate on ecosystems. There are basically two reasons for this. First, arctic ecosystems are structurally simple, which makes them optimal for not only studying direct climate effects on different species but also the so-called indirect effects involving effects which affect the structure and function of the ecosystem. For example, any climate effects on plant growth and flowering may potentially affect herbivores such as muskoxen, caribou or lemmings. However, the effect may also go the other way from herbivores to plants. So even in a simple ecosystem the effects of climate may become complicated quickly.

The second reason is that the most extreme changes in climate are expected to occur in the Arctic and, hence, we expect to see responses here earlier than elsewhere. Studying arctic ecosystems will enable us to provide general clues of how climate may affect systems elsewhere will.

At Zackenberg we have already seen the consequences of climatic changes. From 1996 to 2005 the average June temperature increased by over 1º C. This was followed by an extension of the growth season by over 3 weeks. The interesting question was whether the species could follow such dramatic changes over just a decade? Surprisingly they could. Plants like the arctic willow bloomed up to 2-3 weeks earlier and also the few arctic insects emerged much earlier during this period of warming. You can read more here.

CA-CP: How are changes in Arctic terrestrial ecosystems affecting the planet, and those of us living in the Europe or the United States?

Dr. Forchhammer: In addition to gaining detailed ecosystem knowledge through studies of climate effects in the Arctic and, hence, how climate in general may affect temperate systems, the changes in the Arctic may influence us profoundly at lower latitudes, primarily through the so-called feedback mechanisms. Usually three feedbacks are considered to be important. First, changes in reflectivity of the surface through snow and ice melt and changes in vegetation cover. Melting of snow and ice, for example, will result in darker surface which will absorb more of the sun's energy. This self-enforcing cycle may potentially accelerate the warming trend globally.

The second feedback concerns the melting ice in the Arctic adding more freshwater to the system potentially slowing the thermohaline circulation with global climate consequences.

The third feedback from the Arctic is through greenhouse gas emissions. Large amounts of carbon are trapped as organic matter in the Arctic permafrost. As the soil melts during summer organic matter is decomposed and methane and carbon dioxide is released to the atmosphere. Warming will increase the decomposition and can create an amplifying loop with increasing amounts of greenhouse gasses released to the atmosphere increasing the global greenhouse effect. The relative importance of this process is, however, uncertain. You can find more information at the Arctic Climate Impact Assessment (ACIA) web site.

View Dr. Forchhammer's presentation at ARCUS's 2008 Annual Meeting and Arctic Forum

Interview with Dr. Drew Shindell, of NASA's Goddard Institute for Space Studies (GISS). August, 2008.

CA-CP: Could you tell us about your research on troposphericozone, a form of global air pollution involved in summertime "smog",and how it contributes to Arctic warming?

Dr. Shindell: At the NASA Goddard Institute for Space Studies(GISS) in New York, we evaluated how ozone in the lowest part of theatmosphere changed surface temperatures over the past 100 years. Usingthe best available estimates of global emissions of gases that produceozone, the GISS computer model study reveals how much this single airpollutant, and greenhouse gas, has contributed to warming in specificregions of the world.

CA-CP: What did you discover?

Dr. Shindell: According to this new research, ozonewas responsible for one-third to half of the observed warming trend inthe Arctic during winter and spring. Ozone is transported from theindustrialized countries in the Northern Hemisphere to the Arctic quiteefficiently during these seasons. The findings have been published in the American Geophysical Union's Journal of Geophysical Research-Atmospheres.

CA-CP: How does ozone affect the atmosphere?

Dr. Shindell:Ozone plays several different roles in theEarth's atmosphere. In the high-altitude region of the stratosphere,ozone acts to shield the planet from harmful ultraviolet radiation. Inthe lower portion of the atmosphere (the troposphere), ozone can damagehuman health, crops and ecosystems. Ozone is also a greenhouse gas andcontributes to global warming.

Ozone is formed from several other chemicals found in the atmospherenear the Earth's surface that come from both natural sources and humanactivities such as fossil fuel burning, cement manufacturing,fertilizer application and biomass burning. Ozone is one of several airpollutants regulated in the United States by the U. S. EnvironmentalProtection Agency.

CA-CP: How does the ozone affect climate warming?

Dr. Shindell: The impact of ozone air pollution onclimate warming is difficult to pinpoint because, unlike othergreenhouse gases such as carbon dioxide, ozone does not last longenough in the lower atmosphere to spread uniformly around the globe.Its warming impact is much more closely tied to the region itoriginated from. To capture this complex picture, GISS scientists useda suite of three-dimensional computer models that starts with data onozone sources and then tracks how ozone chemically evolved and movedaround the world over the past century.

The warming impact of low-altitude ozone on the Arctic is very small inthe summer months because ozone from other parts of the globe does nothave time to reach the region before it is destroyed by chemicalreactions fueled by ample sunshine. As a result, when it is summertimein the Northern Hemisphere, ozone-induced warming is largest near thesources of ozone emissions. The computer model showed large summerwarming from ozone over western North America and easternEurope/central Asia, areas with high levels of ozone pollution duringthat time of year.

View Dr. Shindell's presentation on the influence of tropospheric ozone on Arctic climate given at the American Meteorological Society's Environmental Science Seminar Series.

View Dr. Shindell's web page at NASA's GISS

Interview with Sean W. Fleming, PhD, PPhys, ACM, Hydrologic Modeller, BC Hydro,
Adjunct Professor, University of British Columbia. July, 2008.

CA-CP: What is the focus of your research?

Dr. Fleming: My research and applications work has considered, among other things, how the presence of glaciers in a watershed affects the way that river flows respond to climatic variability and change.

"Climatic variability" includes naturally organized patterns in the large-scale circulation of the atmosphere and oceans. The best-known example would be El Niño-Southern Oscillation. This is a sometimes quite severe but relatively short-term type of climatic variation, reflecting individual El Niño or La Niña events for example, which typically last for maybe a year. Although its source area lies nominally in the tropical Pacific Ocean, it affects everything from landslides in California, to fisheries production in the Pacific Northwest, to hurricane activity in the Atlantic, to water resource availability over considerable portions of the planet. Even impacts to stock market performance have been suggested - though if that's true, such effects may have a lot to do simply with people's subjective perceptions of how an anticipated El Niño event might conceivably affect the economy!

"Climate change," on the other hand, involves long-term drift in the climate system, such as an overall tendency toward warmer temperatures. These more persistent changes may arise from a variety of factors, ranging from planetary orbital variations, to complex fractal or chaotic dynamics in the climate system, to human modification of global climate through deforestation and fossil fuel combustion (both of which are of course related to human population growth).

By careful analysis of historical data records, my colleagues and I have found that whether a glacier is or isn't present in a catchment's headwaters can make a huge practical difference in terms of the downstream water resource impacts of climatic variability and change. As always, though, there's some fine print: although the laws of nature don't vary from one watershed or climatic region to the next, the particular ways in which they are locally expressed do. That translates into considerable remaining uncertainty as to how glaciers modify a given river's response to climatic variability and change. There is still a great deal to be learned.

CA-CP: How does glacial melt affect different societies, species, and ecosystems? Why should people living in the United States or Europe be mindful of what is occurring with glaciers and climate change?

Dr. Fleming: Melting of mountain glaciers affects societies in a variety of ways. Some are direct and tangible. For others, the lines linking cause and ultimate effect are more circuitous, though the end result may be no less important. I'll give two examples.

Glaciers are a key source of freshwater - for drinking water supplies, to support agricultural and industrial production, and to drive hydroelectric power generation. One might be tempted to think of glaciers as being a trademark of the frozen north, but altitude can serve as a substitute for latitude: glacial water supplies play an important role through mountainous regions in much of western North America, central Europe, parts of South America, and of course the Himalayas - where glaciers serve as a water source for the world's two most populous nations, India and China. So the implications of climate-driven glacier changes are very far from being strictly academic, particularly if one considers the wider social and economic implications of changes in water supply availability, and in regions where water supplies are already limited due to either quantity or quality issues.

There are also likely to be ecological implications. Unfortunately, the relationships between the cryosphere, freshwater ecosystems, and climatic variability and change are far from well-understood. We're talking about multi-faceted interactions between a number of systems, each of which is in turn complex and nonlinear. But the working hypothesis - and it's a reasonable one - is that the gradual recession, and in some cases eventual disappearance, of mountain glaciers may have far-reaching ecological impacts. Take salmon along the Pacific coast of North America, for example. There is evidence that the relatively strong late-summer baseflows supported by glacial melt may be strongly beneficial for salmon, especially during spawning. Salmon here are a key ecosystem component. They are a food source for other forms of aquatic life, as well as for eagles, bears, and wolves; and they even help sustain the rich rainforests through which the region's rivers flow, as the spawned-out carcasses serve as a natural source of plant nutrients. Further, strong salmon runs are crucial to traditional First Nations fisheries, to the lucrative recreational angling and tourism industries, and of course to the commercial salmon fishery - as well as all the other economic sectors which indirectly benefit from such activity, ranging from boat sales to local restaurants. Again, the implications of coupled climate and glacier change may be profound and of importance to everyone.

CA-CP: What is Arctic Oscillation and how does your research relate to it?

Dr. Fleming: The Arctic Oscillation is a type of atmospheric circulation pattern - an organized, though not entirely predictable, way in which the climate varies. There are several such patterns; probably the best-known is El Niño-Southern Oscillation. The Arctic Oscillation is a northern-hemisphere effect, though there is a southern-hemisphere counterpart called (logically enough) the Antarctic Oscillation. It was only discovered in the 1990s, although yet another pattern, called the North Atlantic Oscillation, appears to be closely related to it and was identified much earlier.

Perhaps because it's a newer discovery, less is known about the effects of the Arctic Oscillation relative to many other climatic variability patterns, such as El Niño or La Niña events. My colleagues and I sought to identify whether - and if so, how - the climate, glaciers, and rivers in the southwest portion of Canada's Yukon Territory respond to the Arctic Oscillation. This is a highly remote subarctic area, but a scientifically important one. Its remoteness has helped the region largely escape development, and it remains very ecologically rich. It also hosts the St. Elias Icefield, which is the largest ice mass outside Greenland and Antarctica, and which helps make it a great natural observatory for studying mountain glaciers and glacier change. And for such a remote and pristine region (data tend to be collected where people live!), there was a reasonable amount of historical meteorological and streamflow records to work with.

In a nutshell, the end result was what we called "selective teleconnectivity": the water resource productivity of glacier-fed rivers in the region was coupled to the Arctic Oscillation, whereas in snowmelt-fed rivers devoid of glacial ice, only the timing of the seasonal melt freshet showed a relationship. Again, there's much still to be learned, but it appears this result has to do with the way the Arctic Oscillation apparently modifies spring temperatures in that region, and how this effect may in turn interact with the presence or absence of a glacier within the watershed, which - put simply - amounts to a gigantic ice cube potentially available for melt production.

View Dr. Fleming's faculty homepage

Interview with Sheldon Drobot, June of 2008

CA-CP: What is the focus of your research in the Arctic?

Drobot: My research focuses on Arctic sea-ice, one of the most compelling stories of a changing planet.

Over the modern satellite record (1979-present), the extent of Arctic sea-ice has declined significantly. Based on a sea-ice record extending back to 1950, last year's minimum ice cover represents a 50% reduction compared to conditions in the 1950s - 1970s (EOS, January 2008) The decline in sea-ice coverage is related to numerous factors, including warming air temperatures, variations in wind direction, which moves the ice, and a thinning ice cover (see GRL, December 2007, GRL, July 2003). Computer models and scientists agree that the sea ice will continue to decline in the future. Based on current sea-ice and atmospheric conditions, my research group is predicting a 3-in-5 chance that the 2008 sea-ice cover will set another new record low (University of Colorado, April 2008). (Photo copyright Sheldon Drobot. Used with permission.)

Graphics

Graphic 1, 2008 Ice Age Data, is a spatial map of the recent ice age compared to climatology. The basic idea behind it is that younger ice is thinner and more responsive to atmospheric conditions. So, the thin, young ice cover we are now seeing is likely to readily respond to slight changes in temperature or wind, and conditions that in the past may not have affected the ice as much may now lead to rapid changes.

Graphic 2, the Concentration Trend Map, is the decadal trend (from 1979-2007) in September sea-ice concentration. So, "-20" would mean every decade we are losing 20% of the ice cover in that area. As an example, since we're now almost 3 decades in, "-20" would mean something like there is 60% less ice in that area now as compared with the early 1980s. What is really striking here is the massive ice loss near Alaska.

CA-CP: What do changes in sea ice mean for the planet?

Drobot: This is an important question, and one that I don't think is asked enough. One effect will be the opening of the Arctic Ocean to increased maritime travel, possibly including a navigable Northwest Passage in the near future. Efficient shipping operations in the Arctic will require long-range sea ice forecasts. My research group recently developed several Arctic-wide and regional sea-ice forecasts (University of Colorado, March 2007, GRL, May 2006, University of Colorado, May 2003).

CA-CP: What does this mean for people living in the United States?

Drobot: There are other impacts of sea-ice decline. These include the possibility of less precipitation in the western USA and the loss of polar bear habitat. These are critical issues that society needs to address soon. Finally, there are some largely unknown consequences of Arctic sea-ice melt, including how the loss of sea ice will affect weather patterns over the central US, and I am involved in research with scientists at the University of Nebraska to look at this now. If the loss of ice changes rainfall patterns over our nation's agricultural belt, this obviously will have an enormous impact on our nation - and the world.

Sheldon Drobot's research can be found on his website.

Interview with Dr. Walt Meier, Research Scientist at NSIDC, June of 2008

CA-CP: What is the focus of your research?

Dr. Meier: I am a research scientist at the National Snow and Ice Data Center (NSIDC), University of Colorado, Boulder. I study sea ice, primarily using data acquired from satellite sensors. The sea ice data comprise one of the longest and most complete climate records, providing a nearly complete daily record of sea ice conditions since late 1978. This makes sea ice an important long-term indicator of climate change. Besides the length of the record, sea ice is an important component of climate because it is a cap between the ocean below and the atmosphere above. Thus, sea ice significantly affects the surface energy balance.

CA-CP: What have you discovered through your research?

Dr. Meier: My colleagues and I have been examining these satellite records and have found significant downward trends in Arctic sea ice, particularly during summer. It is during summer that such decreases are most crucial because the more reflective sea ice absorbs far less energy from the 24-hour summer sunlight than the darker, more absorptive ocean. Thus sea ice is an amplifying factor of the initial atmospheric warming, resulting in greater warming in the Arctic than the rest of the planet. The declining sea ice also impacts wildlife (such as polar bears), native peoples living in the area, as well as commercial and military interests in the region.

My colleagues and I at NSIDC have been tracking the declining Arctic sea ice, examining the causes of the decline and investigate current and future impacts of the decline.

CA-CP: What are the implications of the decreasing Arctic sea ice you have been studying to people living in lower latitudes like the United States?

Dr. Meier: At this point it's hard to say exactly what the effects of decreasing sea ice mean to people living in the U.S., but there are sure to be some significant impacts. If the Arctic becomes sea ice free during the summer, which is likely in the 2-3 decades (if not sooner), this will substantially affect wind and ocean current circulation patterns. The large-scale circulations, things like the jet stream, are at least partly due to the difference in heating between the lower latitudes and higher latitudes. Without sea ice, which keeps the Arctic cooler than it normally would be, the Arctic will be warmer and the temperature difference between lower latitudes and higher latitudes will be less.

This will surely alter things like the jet stream and this will change weather patterns. Climate models are not yet good enough to say exactly how things will change, but one thing likely impacted will be precipitation. Some preliminary model studies suggest this - for example, the American southwest, already a dry region with water resource issues, may become even drier in the future without Arctic sea ice during summer.

More information on the retreating Arctic sea ice, with regular updates through the year, can be found at the NSIDC Sea Ice News and Analysis web page. Further information on my research can be found at here.
For more general information on sea ice, see NSIDC's "All About Sea Ice". For regular updates of sea ice conditions, trends, variability, and browse imagery, see the NSIDC Sea Ice Index page.

Images:
http://nsidc.org/arcticseaicenews/
Source: National Snow and Ice Data Center

Dr. Gearheard: I work with Inuit hunters and elders to document their knowledge and observations of the environment and environmental change. I work mainly in the Baffin region of Nunavut, Canada, and I live in an Inuit community called Clyde River, on Baffin Island I work with scientists as well and coordinate projects that bring Inuit and scientists together to design and carry out research.I really enjoy the challenge of bringing different skills, experiences, and perspectives together, and I love working with multicultural, multidisciplinary teams.I've worked on many different projects with Inuit over the years, from grizzly bears to walrus to vegetation to weather.Most recently, I've been working on several projects about sea ice,working in Nunavut, Greenland, and Alaska.Also, I have worked with different technologies to document and communicate Inuit knowledge of the environment including CD-ROM technology and interactive GPS. CA-CP: How can Inuit and scientists work together to understand environmental change?

Dr. Gearheard: Inuit and their ancestors have lived in the Arctic for thousands of years.Inuit elders today have spent a lifetime living on the land.Inuit hunters have traditional knowledge passed onto them from older people and they combine that knowledge with their own experiences and skills.Through a close relationship with the natural environment, and through constant observation and use, Inuit have a complex understanding of environmental patterns, processes, and changes.

Inuit and scientists can help each other in the quest to understand how the Arctic is changing.They use different knowledge and different tools, but both contribute very important information.For example, scientists use satellites to study sea ice.This allows them to see sea ice on a very large scale, over the entire Arctic, and how sea ice margins are advancing or retreating.Inuit study sea ice through intense use (travel, hunting, fishing) and have knowledge and observations at the local and regional scale.Inuit have constant and direct contact with sea ice - touching, tasting, and probing it to get detailed information.Combining these different scales, tools, and methods from both scientific and Inuit knowledge, we can get a more complete picture of how sea ice is changing.

CA-CP: What can people in the United States learn from this kind of collaboration?

Dr. Gearheard: There are local experts everywhere who have knowledge about their environment and who can teach us very important skills.Experienced farmers, fisherpeople, pilots, foresters, ski patrol, and ranchers are just a few examples of people who have close relationships with the environment and have direct observations about how the environment has changed over time. Many scientists are already partnering with people who have local knowledge and we could increase these collaborations.The more knowledge and experience we can pull together in studying the environment, the more complete picture we can assemble about how the environment is changing.

All photos Copyright Shari Gearheard. Used with permission. See more photos here.

For more information about indigenous peoples and Arctic change visit:

Indigenous Peoples Secretariat

Arctic Climate Impact Assessment

Inuit Circumpolar Council

Exchange for Local Observations and Knowledge of the Arctic

Read more about Dr. Gearheard's projects at NSIDC here.

Interview with BROOKS YEAGER, Executive Vice President for Policy, Clean Air-Cool Planet

CA-CP: What are the major impacts that climate change is having on the Arctic?

Brooks: There are two kinds of impacts from climate change: direct and indirect. Direct impacts include loss of sea ice, release of water from Greenland, more water flowing into the Arctic Ocean from Russian rivers causing thermal changes in the region, etc. There are also many indirect impacts, some of which are starting already and some that are just on the horizon. Many of these are commercial and economic activities that are now taking place due to major Arctic sea ice melt. For example, we are now seeing industrial fishing in places that have always been protected by ice. Icelandic and Norwegian fishing vessels are venturing north of the Svalbard Archipelago for the first time. We'll likely see an increase in shipping of all kinds, including trans-continental voyages. There are already increases in oil exploration and shipping in the Barents, Beaufort, and Chukchi Seas. There's been an increase in tourist boats, particularly around Greenland. There have been innumerable impacts on traditional cultures, particularly the Inuit, but also on reindeer herders in Europe. They no longer have access to the ice-covered sea that is imperative to their way of life due to the recession of summer sea ice.

CA-CP: What sort of governance structures are in place to help deal with these changes?

Brooks: Almost all the real governance done in the Arctic is done on a national level. It's a veritable policy "smorgasbord" and not particularly well-coordinated. There are some encouraging examples of very progressive action, including Norway's major ecosystem assessment plan for the Barents Sea. In the US, all our planning has been done by the Mineral Management Service, not by the National Oceanic and Atmospheric Agency (NOAA) because that's where the resources to do the studies are - in mining and extractive industries. There is a degree of coordination done by the Arctic Council, an innovative body that is mostly a forum for conversation, and is not a regulatory body. It's innovative because in addition to the eight Arctic countries, there are permanent representatives from indigenous nations, a successful and creative incorporation of civil society. It's been a very successful regional cooperation, producing studies like AMAP and the Arctic Human Development Report, but unfortunately in the end it has no authority to make decisions.

CA-CP: Are you optimistic about policymakers' ability to successfully solve the crisis facing the Arctic?

Brooks: I'm optimistic in the following sense: up until 4 or 5 years ago, no government thought the Arctic was a policy priority at all, except maybe Norway. All the press attention that Arctic warming has attracted in the past few years has made it a much higher priority, and there's real evidence that the Arctic nations are interested in working together on this stuff.

At the meeting in Tromso, there was actually a lot of talk about the need to manage the Arctic in a way that keeps life in the Arctic sustainable while times are changing. Those discussions in tandem with the implications of these issues in the Copenhagen process are creating an emerging sense of importance for the Arctic, as well as a sense of peril.

CA-CP: What policy would you implement if you had complete control? What are you striving toward?

Brooks: I would create a much more coordinated and consistent approach to managing the resources of the Arctic, utilizing the Arctic Council, but also the new tools of ecosystem management and integrated spatial planning.

CA-CP: In what ways could an average citizen get involved?

Brooks: There are several things one can do to help fight Arctic warming:

• Recognize that for Americans, the Arctic really is our backyard, and that it's a unique ecosystem with spectacular wildlife and other values to humanity and accordingly call for its protection in the strongest possible terms.
• Pay attention to the traditional uses of the Arctic and do what you can to preserve that even in the face of a warming world and changing climate.
• Most importantly, work as hard and as fast as possible to limit your own greenhouse gas emissions.