Non-Forested Wetlands

There is a greater likelihood of reduced soil moisture and enhanced evapotranspiration as the climate warms, especially late in the growing season. Drought stress and mortality may consequently increase, with the greatest risk on dry and poor-quality sites. Additionally, projected temperatures may be beyond the physiological limits of aspen and birch species by the end of the 21st century, particularly under hotter climate scenarios.

Soil moisture is expected to change in response to warmer temperatures and seasonal changes in precipitation. Changes are likely to vary seasonally as well as geographically. More intense and prolonged precipitation events would be expected to create wetter soil conditions, while increased temperatures and less frequent rainfall events would lead to drier soils .

Model results project that species currently near their northern range limits in the region may become more abundant and more widespread under a range of climate futures.Results from forest impact models suggest that species such as black cherry, chestnut oak, and yellow-poplar may have increases in both suitable habitat and biomass, and some deciduous forest types have the potential for productivity increases across the assessment area.

Across northern latitudes, warmer temperatures are expected to be more favorable to individuals near the northern extent of their species’ range and less favorable to those near the southern extent.Results from climate impact models project a decline in suitable habitat and landscape-level biomass for northern species such as black spruce, red spruce, tamarack, and paper birch, as well as spruce-fir forest communities. These northern species may persist in the region throughout the 21st century, although with declining vigor.

Many invasive species that currently threaten regional forests may benefit directly from projected climate change or benefit from the relatively slower adaptation response of native species. Increases in carbon dioxide increase growth for many plant species, andcChanges in climate may have allowed some invasive plant species to expand their ranges northward, including bush honeysuckle, privet, and kudzu. Some invasive species are tolerant of drought, fire, flooding, and other disturbances and may be at an even greater advantage under future climate conditions.

A variety of models project that winters will become more mild across New England and northern New York as temperatures increase. Warmer temperatures will cause more winter precipitation to be delivered as rain. Snowfall, snow depth, and snow pack duration are all expected to be reduced.

Shorter-term fluctuations in the variability of ocean dynamics, atmospheric shifts, and ice mass loss from Greenland and Antarctica have been connected to recent accelerations in the sea level rise rate in this region. Sea levels have risen over the past century, and all global climate models agree that sea level will rise over the next century. Worst-case and lowest-probability scenarios project that sea levels in the region could rise upwards of 11 feet (3 m) on average by the end of the century.

Heavy precipitation events have increased substantially in number and severity in the across the Northeast over the last century, and many models agree that this trend will continue over the next century. Extreme precipitation events could lead to more frequent or severe flooding and an increase in soil erosion. Monthly precipitation in the Northeast is projected to be about 1 inch greater for December through April by end of century (2070–2100) under a high emissions scenario.

All global climate models agree that there will be changes in precipitation patterns across the assessment area, but there is large variability among projections of future precipitation. Most climate models project increases in annual precipitation. Seasonally, winter and spring are also generally projected to have increases in precipitation during the next century. Projections of summer and fall precipitation for this region vary, with many models projecting decreased precipitation or only very slight increases.

Evidence at both global and local scales indicates that growing seasons have been getting longer, and this trend is projected to become even more pronounced over the next century. Warmer temperatures will result in fewer days with minimum temperatures below 32°F and a shorter freeze-free season.