CA-CP Announces Changing Calendar

Early Spring Brought To You By Global Warming?

You could say the first day of spring came week earlier this year: Monday, March 13th. 

What's the connection with global warming?

Over the last 150 years, scientific measurements show that events signifying the beginning of spring - including when plants bud, sap flows, ice breaks up, and the last frost and final 32-degree day occur - have all shifted. These events now happen a week earlier on average, according to a new report:
Evidence of Early Spring (PDF, 249 KB)

These trends are consistent with what computer models have predicted would happen with global warming.

“Of course, the sun will still cross the equator on the 20th, marking the vernal equinox,  but biological spring has changed due to global warming and that’s threatening to put ecosystems badly out of synch,” said Adam Markham, executive director at CA-CP.

" What matters to us is when we can shed the winter clothes, when we see the crocuses and daffodils and smell the lilacs, when spring actually arrives," Markham said. "That time is coming earlier and earlier – much earlier than it did a century ago.”

“All of the major indicators of climate here in the Northeast, from temperature and length of growing season, to lake ice-out and lilac bloom and apple blossom time, are showing that spring is at least a week earlier now than it was in1850.”

Clean Air-Cool Planet and University of New Hampshire Climate Scientist Cameron Wake released Indicators of the Climate Change in the Northeast, a comprehensive look at 11 different physical and biological markers of the changing climate in the region.

“Climate researchers had known for some time that various trends were emerging in the long-term data sets for things like temperature, precipitation, day with snow on the ground, length of growing season, as well as bloom dates,” said Wake, a research associate professor at the Climate Change Research Center in UNH’s Institute for the Study of Earth, Oceans and Space.

“Working with researchers from Cornell, US Geological Survey, and others, we’ve been able to bring this data together in one place for the first time, and analyze it for consistent trends.”

What the data shows, says Markham, is that things are changing rapidly in the Northeast, and changing along the lines projected by various global models of climate change resulting from global warming.  And the clearest signal, he says, is the shift in late winter and early spring conditions.

“Many of the indicators associated with end-of-winter or the beginning of the growing season show very uniform movement – about a week – earlier.  This is consistent with predictions, and it is scientific evidence that we don’t need to wait decades or years to see dramatic climate change – it’s happening all around us right now” Markham says.

The following indicators show average changes as indicated:

Growing season:                      8 days longer

Spring bloom:                           4 – 8 days earlier

High-volume spring river flow: 7 – 14 days earlier

 Lake ice-out:                           9 – 16 days earlier

Days with snow on ground: 16 fewer days

One of the contributors to the indicators report, Dr. David Wolfe from the Horticulture Department at Cornell University, collected biological data on bloom dates for apples, grapes, and lilacs.

“Collectively, analyses for the northeastern U.S. indicate that, on average, lilacs are blooming about four days earlier, and apple and grapes are blooming about eight days earlier than they were half a century ago,” Wolfe noted in his report, while cautioning that the earlier start to the growing season indicated by the data may not be a good thing.

“Farmers may tend to look at this and say that it’s good, because they will get an earlier yield.  But earlier bloom dates make these species more susceptible to damage from frost,” he said, “and analysis of data on apple yields indicates that warmer temperatures from January 1 to bud break correlated with lower yields, not higher.”

Wolfe also reported that the magnitude of the impact of earlier bloom dates on woody perennials in the Northeast “is similar to that reported for bloom of other plant species, and for bird and insect spring migration arrivals, by researchers in other parts of the U.S. and Europe.”  He said findings are also “qualitatively in agreement with reports of earlier spring ‘green wave’ advancement in the northern hemisphere based on satellite imagery of vegetative cover,” both observations supporting the findings.

Markham said these indicators are ominous for some species, based on research done in Britain and beginning to be done here.

“Studies show that for species whose migration, for instance, is triggered by length of day, and so arrive at their warmer-weather homes at the same time each year, there is now occurring a ‘mismatch’ with traditional food sources, including insects and plants.

“The larval stages of insects, for example, are often controlled by temperature, so the worm the birds have fed on for centuries may now be a butterfly before the birds get there.  The result,” Markham said, “is a plunge in reproductive rates for the birds – and a plague of the insects. It may now be the case that because of global warming, the early bird no longer gets the worm”

Markham noted that we don’t know “where this kind of interference with the climate system will lead us. But we have already begun to see disruptions in traditional economies like maple sugaring and ski tourism, and it’s likely these are harbingers of major disruptions to come.”

The remarkable thing about the findings, according to Wake, is the consistency.  “Despite the fact that this evidence comes from a wide range of environments – the atmosphere, the biosphere, the oceans, and snow and ice – the remarkably consistent signal of a warming trend across the region cannot and should not be ignored. We now have our canary in the coal mine.”

Markham agrees: “For those who are still asking for scientific evidence supporting the notion that we are already seeing the kinds of effects scientists have been warning us we’d see from global warming, here it is.”