The Northeast and Midwest regions of the United States cover enormous diversity in geography, climate, biological diversity, and human land use. The Northeast region contains 22 states, multiple ecoregions, seven of the 21 regions established for the National Landscape Conservation Cooperative (LCC) Program, and a human population of 131,000,000 (41% of the US population). Consequently, the Northeast region poses many unique challenges for understanding, adapting to and mitigating the effects of climate change, including:
- Extreme gradients in environments and threats manifested over relatively modest spatial scales – from rapidly expanding and developing coastal regions and urban areas to depopulating rural communities, but with the common thread that the natural resources of the region are inextricably intertwined with human use and human infrastructure – both past and present.
- A pattern of land ownership and administration dominated by relatively small, privately- owned parcels, and limited federal lands. Consequently, the interactions between land use and climate change adaptation and mitigation will emerge from a multitude of complex local decisions; yet, many critical ecological processes operate at larger landscape scales.
- A complex history of species extirpations, invasions, range extensions, and restorations.
- Complex predictions of regional climate change and associated responses of species and natural communities, with the likelihood that some species are likely to decline or be lost from the region, while others will expand.
- A wide array of stakeholders and decisions makers.
Climate change is already affecting the physical and biological environments of the Northeast Region, and is expected to intensify in coming decades. Temperatures have risen by ~0.7°C over the last century and are projected to rise by a further 3-5°C under probable emission scenarios. As a consequence of increasing temperatures, sea level will rise by at least 1m this century, with even greater coastal impacts from storm surges in areas that have seen major population increases. Increasing temperatures have also affected altitudinal and range shifts in species, and earlier seasonal migrations for migratory animals, a trend that will be reinforced further in the future. The Northeast region has recorded higher amounts of precipitation over the last 50 years, with a greater frequency of extreme events and all model simulations for the future point to wetter winter and spring conditions, but much drier summers and falls. This will increase overall runoff but shift the timing of peak flows of rivers to earlier in the spring, with longer periods of low flows in the summer months. All of these changes will have profound effects on aquatic and terrestrial ecosystems across the region, changing forest types and aquatic environments, affecting fish community structure and the timing of migratory fishes. Understanding how climate affects habitats and other conditions for fish and wildlife populations will be essential for decision makers challenged with balancing multiple land uses, including agriculture, forestry, water allocations, energy, and transportation. Obtaining the best regional estimates for a range of probable climate change scenarios is a critical task to aid natural resource managers and other stakeholders.