DURHAM, N.H. -- If nothing is done to reduce the amount of carbon dioxide
pumped into the atmosphere, the average temperature in New England and upstate
New York is likely to increase by 6? to 10? F over the next century. In addition to
temperature change, the region may experience increases in precipitation from 10 to
30 percent. These changes, if they occur, would profoundly affect the New England
region, with major impacts expected on weather, air quality, human health, the natural
environment and the regional economy.
This is the conclusion of a new report released by the University of New Hampshire's Institute for the Study of Earth, Oceans, and Space. The New England Regional Assessment (NERA) report is one of 16 such regional reports conducted as part of a national assessment of potential climate change impacts and is the product of a four-year effort to characterize the impacts to the region of a changing climate. It examines the current understanding of factors known to influence our regional climate, and the projections of possible future regional climates.
The report presents records of regional average temperatures that show warming of 0.7? F since 1895. Within the region there has been considerable variation in the trend. Rhode Island and New Hampshire have warmed by two to three times the regional average, while Maine has cooled somewhat, most likely the result of re-growing forests which absorb sunlight and cool the land surface.
Warming in winter months has been greater than summer-time warming. The recent milder winters, earlier maple sap flows, earlier dates for ice melting on lakes and reduced snowfall experienced across the New England region are likely responses to this increase in temperature during the past century.
"Human activities are affecting climate," says Barrett Rock, UNH professor of forest resources and the report's lead author. "There is now strong evidence that much of the global warming experienced in the last half of the 20th century is attributable to human factors."
The major culprit is increasing concentrations of atmospheric CO2 caused largely by the burning of fossil fuels, including oil, gasoline, coal and natural gas. To derive future projections scientists used data for the region from two established global climate models used in the U.S. National Assessment of Climate Change Impacts on the United States -- the UK Hadley Model and the Canadian Climate Model. These models were both run into the future, assuming that atmospheric CO2 concentrations increase at 1 percent of 1990 levels throughout the century.
According to George Hurtt, research assistant professor in UNH's Complex Systems Research Center and lead author of the report's chapter on future climates, the models differ primarily in their treatment of the hydrological cycle and cloud dynamics.
"The hydrologic cycle in general, and cloud dynamics in particular, are some of the largest uncertainties in the current models," he says. "This is an area that needs further study and refinement in models to better understand climate change scenarios."
Either temperature increase would be greater than any climatic variation experienced by the region in the past 10,000 years, says Rock, describing what such a warming might mean. "To put the projected changes for the region in perspective, the average temperature for Boston over the 30-year period from 1961 to 1990 was 51.3? F. If that average were to increase by 6? F, as one of the scenarios suggests, then Boston's new average temperature would roughly equal the current 30-year average temperature of Richmond, Virginia -- 57.7? F. If it were to increase by 10? F, as the second model suggests, then Boston's new average temperature would equal Atlanta's current average of 61.3? F."
The report then continues to look at how changes in climate would effect the region. Some of the major findings include:
Regional air quality would worsen. Heat contributes to the formation of smog and sulfate haze, and wetter conditions enable compounds from automobile exhaust and power plants to combine with water vapor and produce acid rain.
Human health will be impacted. Not only will it be affected by increased levels of pollution, but warmer winters can facilitate the expansion of Lyme disease-carrying tick populations.
The natural environment will be altered. The current forest types for the region are primarily maple, beech and birch in the western and central part, oak-hickory in the south coastal part and spruce-fir in northern Maine. Future projections show that oak-hickory could become the dominant species, with oak-pine scattered throughout the northern regions. Maple, beech, birch and spruce-fir could become non-existent under either of the model projections.
Oceans will change. One of the most likely impacts of the warming will be rising sea-levels, resulting from the thermal expansion of sea water (as water warms, its volume increases), the addition of fresh water from melting glaciers, ice sheets and snow pack. Sea-level rise, which is already occurring, could flood coastal areas of the New England region. In addition, warming water may be a contributing factor in the decline of commercially important ground fish such as winter flounder.
The regional economy will suffer. Because warming is expected to increase at a greater rate during winter months, the ski and maple syrup industries will take a major blow. In addition, fall tourism is expect to suffer, as the loss of diverse tree species will impact fall foliage.
Hurtt cautions that the scientists are not making predictions, but are rather projecting the future based on current trends and the best global computer models available today.
"These models were developed for addressing global issues, and are more error-prone on a regional level," says Hurtt. "Still, the evidence that current trends may have dramatic consequences for the region is suggestive enough to warrant further research, assessment and action to reduce uncertainties and help mitigate the problem."
He and Rock both emphasize that the report is based on one scenario which doesn't take into consideration how humans may alter their behavior in the future to mitigate the problem. Both say action must be taken to reduce CO2 emissions and increase energy efficiency, as well as look at ways to manage land use constructively.
"People feel that to change the way we do things would be disastrous to the economy, but that is not the case," says Rock. "Stonyfield Farm Yogurt over the past five years reduced their greenhouse gas emissions by 26 percent and saved half-a-million dollars as a result of the energy saved. The Clean Air Act led to the invention of the catalytic converter and did not result in the demise of the U.S. automobile industry, as predicted by Detroit at the time. People are innovative, and new emission standards will create new markets."
"There are some who say that there is high uncertainty so we should not act," adds Hurtt. "But people and businesses act in the face of uncertainty all the time. We buy insurance plans for contingencies, and try to minimize bad risks in our daily lives. A strong argument can be made that climate change should be handled in a similar rational manner, not dismissed."
For more information, contact UNH professors Rock or Hurtt at 603-862-1792.
By Sharon Keeler
UNH News Bureau
Additional information available at:http://www.necci.sr.unh.edu/2001-NERA-report.html