Climate Change Impacts in the Northeastern U.S.

Adapted from: T.R. Karl, J.M. Mellilo, and T.C. Peterson (eds.). Global Climate Impacts in the United States. Cambridge University Press, 2009. Available online at USGCRP
The region of the United States that is covered by report on Regional Impacts from the U.S. Global Climate Research Program.





Climate change in the Northeast has meant hotter temperatures, more heavy rains, and less lake ice and snow cover. Northeast annual average temperature has increased by 2 degrees Fahrenheit since 1970, with winter temperatures rising twice this much. The warming has resulted in more frequent unusually hot days and a longer growing season. The region has also experienced an increase in heavy downpours and less winter precipitation falling as snow and more as rain. The warmer temperatures are also leading to an earlier breakup of winter ice on lakes and rivers and an earlier melting of snow, which has pushed forward the typical date of peak river flows. Rising sea surface temperatures and melting global ice have contributed to rising sea levels.

These trends are projected to continue, with more dramatic changes under higher emissions scenarios compared to lower emissions scenarios. Some of the extensive climate-related changes projected for the region could significantly alter the region’s economy, landscape, character, and quality of life.

Key issues include:

  • Extreme heat and declining air quality are likely to pose increasing problems for human health. By late this century, hot summer conditions are projected to arrive three weeks earlier and last three weeks longer into fall, given the scenario of higher greenhouse gas emissions. Cities that currently experience just a few days above 100°F each summer would average 20 such days per summer. Cities like Hartford and Philadelphia would average nearly 30 days over 100°F per summer. In addition, cities that now experience air quality problems would see those problems worsen with rising temperatures, if no additional controls were placed on ozone-causing pollutants.
  • Agricultural production is likely to be adversely affected as climate shifts. Under scenarios of higher greenhouse gas emissions, large portions of the Northeast are likely to become unsuitable for growing popular varieties of apples, blueberries, and cranberries. The climate conditions suitable for maple/beech/birch forests are projected to shift dramatically northward, eventually leaving only a small portion of the Northeast with a maple sugar business and the colorful fall foliage that is part of the region’s iconic character. In short, dairy, fruit, and maple syrup are among the region’s agricultural products that are likely to decline as temperatures rise.
  • Severe flooding due to sea-level rise and heavy downpours is likely to occur more frequently. The densely populated coasts of the Northeast face substantial increases in the extent and frequency of storm surge, coastal flooding, erosion, potential loss of wetlands, and property damage. New York state alone has more than $2.3 trillion in insured coastal property. Much of this coastline is exceptionally vulnerable to sea-level rise and related impacts.
  • Winter recreation and related industries face a reduction in snow cover. The length of the winter snow season would be cut in half across northern New York, Vermont, New Hampshire, and Maine and reduced to just a week or two in southern parts of the region by late this century under a scenario of high greenhouse gas emissions. Winter snow and ice sports, which contribute $7.6 billion annually to the region’s economy, will be particularly affected by warming.
  • Lobster and cod fisheries could be adversely affected. The center of lobster fisheries is projected to continue its northward shift. Lobster catches in the southern part of the region have declined dramatically in the past decade, associated with a temperature-sensitive bacterial shell disease. Analyses also suggest that lobster survival and settlement in northern regions of the Gulf of Maine could increase under warmer conditions. Cod populations, also subject to overfishing and other stresses, are likely to be adversely affected as temperatures continue to rise. The cod fishery on Georges Bank is likely to be diminished.

Adapted for by Melanie Lenart, University of Arizona

Other Regional Climate Change Impacts from USGCRP: