Non-Forested Wetlands

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. Under the higher scenario (RCP8.5) the number of extreme events is projected to increase by two to three times the historical average in every region by the end of the 21st century, with the largest increases in the Northeast. Under the lower scenario (RCP4.5), these events are projected to increase by 50%–100%.

Seasonal differences in temperatures across the Mid-Atlantic and Northeast have decreased in recent years as winters have warmed three times faster than summers. By the middle of this century, winters are projected to be milder still, with fewer cold extremes, particularly across inland and northern portions of the Northeast. Warmer temperatures are expected to cause more winter precipitation to be delivered as rain. Snowfall, snow depth, and snow pack are all expected to be reduced.

Warmer temperatures can lead to decreased soil moisture even without an associated decrease in precipitation, resulting in a temporary inability for a tree to meet water demand.

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. Winter or early-spring warmth has caused plants to start growing and emerge from winter dormancy earlier in the spring.

Temperatures in the Mid-Atlantic region (and across the broader Northeast) are projected to increase on average by 5.27 to 9.11 °F by the end of the century (2070 to 2099), with the greatest warming expected to occur during summer and fall. More warming (9.11 °F) is projected under a high climate scenario (RCP 8.5) and more moderate warming (5.27 °F) is projected under a moderate climate scenario (RCP 4.5).