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Northeast

Bartram Bridge in Pennsylvania

Key Message 1

Changing Seasons Affect Rural Ecosystems, Environments, and Economies
The seasonality of the Northeast is central to the region’s sense of place and is an
important driver of rural economies. Less distinct seasons with milder winter and
earlier spring conditions are already altering ecosystems and environments in ways
that adversely impact tourism, farming, and forestry. The region’s rural industries
and livelihoods are at risk from further changes to forests, wildlife, snowpack, and
streamflow.

Key Message 2
Changing Coastal and Ocean Habitats, Ecosystem Services, and Livelihoods
The Northeast’s coast and ocean support commerce, tourism, and recreation that
are important to the region’s economy and way of life. Warmer ocean temperatures,
sea level rise, and ocean acidification threaten these services. The adaptive capacity
of marine ecosystems and coastal communities will influence ecological and
socioeconomic outcomes as climate risks increase.

Key Message 3
Maintaining Urban Areas and Communities and Their Interconnectedness
The Northeast’s urban centers and their interconnections are regional and national hubs
for cultural and economic activity. Major negative impacts on critical infrastructure,
urban economies, and nationally significant historic sites are already occurring and will
become more common with a changing climate.

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Key Message 4
Threats to Human Health
Changing climate threatens the health and well-being of people in the Northeast
through more extreme weather, warmer temperatures, degradation of air and water
quality, and sea level rise. These environmental changes are expected to lead to healthrelated impacts and costs, including additional deaths, emergency room visits and
hospitalizations, and a lower quality of life. Health impacts are expected to vary by
location, age, current health, and other characteristics of individuals and communities.

Key Message 5
Adaptation to Climate Change Is Underway
Communities in the Northeast are proactively planning and implementing actions to
reduce risks posed by climate change. Using decision support tools to develop and
apply adaptation strategies informs both the value of adopting solutions and the
remaining challenges. Experience since the last assessment provides a foundation to
advance future adaptation efforts.

The distinct seasonality of the Northeast’s
climate supports
a diverse natural
landscape adapted
to the extremes of
cold, snowy winters
and warm to hot,
humid summers.
This natural landscape provides the
economic and cultural foundation for many rural
communities, which are largely supported by a
diverse range of agricultural, tourism, and natural
resource-dependent industries (see Ch. 10: Ag &
Rural, Key Message 4). The recent dominant trend
in precipitation throughout the Northeast has
been towards increases in rainfall intensity, with
increases in intensity exceeding those in other
regions of the contiguous United States. Further
increases in rainfall intensity are expected, with
increases in total precipitation expected during
the winter and spring but with little change in the
summer. Monthly precipitation in the Northeast

is projected to be about 1 inch greater for December through April by end of century (2070–2100)
under the higher scenario (RCP8.5).
Ocean and coastal ecosystems are being affected
by large changes in a variety of climate-related
environmental conditions. These ecosystems
support fishing and aquaculture, tourism and
recreation, and coastal communities. Observed
and projected increases in temperature, acidification, storm frequency and intensity, and sea
levels are of particular concern for coastal and
ocean ecosystems, as well as local communities
and their interconnected social and economic
systems. Increasing temperatures and changing
seasonality on the Northeast Continental Shelf
have affected marine organisms and the ecosystem in various ways. The warming trend experienced in the Northeast Continental Shelf has
been associated with many fish and invertebrate
species moving northward and to greater depths.
Because of the diversity of the Northeast’s coastal
landscape, the impacts from storms and sea level
rise will vary at different locations along the coast.

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Northeastern cities, with their abundance
of concrete and asphalt and relative lack of
vegetation, tend to have higher temperatures
than surrounding regions due to the urban
heat island effect. During extreme heat events,
nighttime temperatures in the region’s big
cities are generally several degrees higher than
surrounding regions, leading to higher risk
of heat-related death. Urban areas are at risk
for large numbers of evacuated and displaced
populations and damaged infrastructure due to
both extreme precipitation events and recurrent flooding, potentially requiring significant
emergency response efforts and consideration
of a long-term commitment to rebuilding and
adaptation, and/or support for relocation
where needed. Much of the infrastructure in
the Northeast, including drainage and sewer
systems, flood and storm protection assets,
transportation systems, and power supply, is
nearing the end of its planned life expectancy.
Climate-related disruptions will only exacerbate existing issues with aging infrastructure.
Sea level rise has amplified storm impacts in
the Northeast (Key Message 2), contributing
to higher surges that extend farther inland, as
demonstrated in New York City in the aftermath of Superstorm Sandy in 2012. Service and
resource supply infrastructure in the Northeast
is at increasing risk of disruption, resulting
in lower quality of life, economic declines,
and increased social inequality. Loss of public
services affects the capacity of communities
to function as administrative and economic
centers and triggers disruptions of interconnected supply chains (Ch. 16: International,
Key Message 1).
Increases in annual average temperatures
across the Northeast range from less than 1°F
(0.6°C) in West Virginia to about 3°F (1.7°C) or
more in New England since 1901. Although the
relative risk of death on very hot days is lower
today than it was a few decades ago, heatrelated illness and death remain significant

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public health problems in the Northeast. For
example, a study in New York City estimated
that in 2013 there were 133 excess deaths due
to extreme heat. These projected increases in
temperature are expected to lead to substantially more premature deaths, hospital admissions, and emergency department visits across
the Northeast. For example, in the Northeast
we can expect approximately 650 additional
premature deaths per year from extreme heat
by the year 2050 under either a lower (RCP4.5)
or higher (RCP8.5) scenario and from 960
(under RCP4.5) to 2,300 (under RCP8.5) more
premature deaths per year by 2090.
Communities, towns, cities, counties, states,
and tribes across the Northeast are engaged
in efforts to build resilience to environmental
challenges and adapt to a changing climate.
Developing and implementing climate adaptation strategies in daily practice often occur in
collaboration with state and federal agencies.
Advances in rural towns, cities, and suburban
areas include low-cost adjustments of existing
building codes and standards. In coastal areas,
partnerships among local communities and
federal and state agencies leverage federal
adaptation tools and decision support frameworks. Increasingly, cities and towns across
the Northeast are developing or implementing
plans for adaptation and resilience in the
face of changing climate. The approaches
are designed to maintain and enhance the
everyday lives of residents and promote economic development. In some cities, adaptation
planning has been used to respond to present
and future challenges in the built environment.
Regional efforts have recommended changes
in design standards when building, replacing,
or retrofitting infrastructure to account for a
changing climate.
For full chapter, including references and
Traceable Accounts, see https://nca2018.
globalchange.gov/chapter/northeast.

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Lengthening of the Freeze-Free Period

These maps show projected shifts in the date of the last spring freeze (left column) and the date of the first fall freeze (right
column) for the middle of the century (as compared to 1979–2008) under the lower scenario (RCP4.5; top row) and the higher
scenario (RCP8.5; middle row). The bottom row shows the shift in these dates for the end of the century under the higher
scenario. By the middle of the century, the freeze-free period across much of the Northeast is expected to lengthen by as much
as two weeks under the lower scenario and by two to three weeks under the higher scenario. By the end of the century, the
freeze-free period is expected to increase by at least three weeks over most of the region. From Figure 18.3 (Source: adapted
from Wolfe et al. 2018).

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Coastal Impacts of Climate Change

(top) The northeastern coastal landscape is composed of uplands and forested areas, wetlands and estuarine systems, mainland
and barrier beaches, bluffs, headlands, and rocky shores, as well as developed areas, all of which provide a variety of important
services to people and species. (bottom) Future impacts from intense storm activity and sea level rise will vary across the
landscape, requiring a variety of adaptation strategies if people, habitats, traditions, and livelihoods are to be protected. From
Figure 18.7 (Source: U.S. Geological Survey).

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