40

he Northeast is characterized by diverse waterways, extensive shorelines,

and a varied landscape. The contrasts,from mountain vistas and extensive

forests to one of the most densely populated corridors in the US,are noteworthy. The Northeast includes the largest financial market in the world (New York

City),the nation’s most productive non-irrigated agricultural county (Lancaster,

PA),and the largest estuarine region (the Chesapeake Bay) in the US. The

Northeast is dominated by managed vegetation, with much of the landscape

covered by a mosaic of farmland and forest. The varied physical setting of the

Northeast is matched by its highly diversified economy. The majority of the

population is concentrated in the coastal plain and piedmont regions,and in

major urban areas. Economic activities in the region include agriculture,

resource extraction (forestry, fisheries,and mining),major service industries

highly dependent on communication and travel,recreation and tourism,and

manufacturing and transportation of industrial goods and materials.

Observed Climate Trends

istorically, the Northeast has experienced significant variability and

extreme events related to weather and climate. Floods,droughts,heat

waves,and severe storms are characteristic. For example,seven major tropical

storms have crossed the mid-Atlantic region since 1986 and six years of the last

20 have been characterized by significant drought. In addition,the major cities

of the Northeast have experienced episodes of increased illness and deaths during heat waves. Temperature increases of as much as 4°F (2oC) over the last

100 years have occurred along the coastal margins from the Chesapeake Bay

through Maine. Precipitation has generally increased,with trends greater than

20% over the last 100 years occurring in much of the region. Precipitation

extremes appear to be increasing while the amount of land area experiencing

drought appears to be decreasing. For the region as a whole,the period

between the first and last dates with snow on the ground has decreased by 7

days over the last 50 years.

The Vulnerability of Urban

Transportation Systems

Historical events often illustrate vulnerabilities. The December 11-12, 1992 nor'easter

produced some of the worst flooding and

strongest winds on record for the area. It

resulted in a near shutdown of the New

York metropolitan transportation system and

evacuation of many seaside communities in

New Jersey and Long Island. This storm

provided a "wake-up" call, indicating the

vulnerability of the transportation system to

major nor'easters and hurricanes. Critical

transportation systems are only 7 to 20 feet

above current sea level. Had flood levels

been only 1 to 2 feet above the actual 8.5

foot high water, massive inundation of rail

and subway tunnels could have resulted,

with possible loss of life. There is a possibility that sea-level rise due to climate

change will add 1 to 3 feet to all surge

heights by 2100, so even a weaker storm

would produce damage comparable to the

1992 storm. The construction of dikes and

pumping stations and the institution of

effective warning systems are possible

H

NORTHEAST

T

KEY ISSUES

• Increase in Weather

Extremes

• Stresses on Estuaries,

Bays, and Wetlands

• Multiple Stresses on

Urban Areas

• Recreation Shifts

• Human Health

• Species Changes
Temperature Change - 20th & 21st Centuries

41

adaptation strategies. While hurricanes are

much less frequent than nor'easters in the

Metro East region, they can be even more

destructive because the geometry of the

coast amplifies surge levels toward the New

York City harbor. For a worst-case scenario

category 3 hurricane, surge levels could

rise 25 feet above mean sea level at JFK

Airport and 21 feet at the Lincoln Tunnel

entrance.

Precipitation Change - 20th & 21st Centuries

Observed 20th Canadian Model 21st

The Canadian model scenario for the next century

indicates near neutral

trends or modest increases,

while the Hadley model projects increases of near 25%

for the region. 

Observed precipitation

changes during the last

century are a

patchwork of

moderate

increases and

decreases. 

100%

75%

50%

25%

0

-25%

-50%

-75%

-100%

100%

80%

60%

40%

20%

0

-20%

-40%

-60%

-80%

-100%

Hadley Model 21st

Observed 20th Canadian Model 21st

Future model scenarios

project relatively uniform

increases in annually averaged temperatures.

However, the Canadian

model projects increases

that are twice as large as

the Hadley model.

The largest

warming during the last

century has

occurred

along the

coastal region

(as much as

4oF). 

Hadley Model 21st

Scenarios of Future Climate 

he Northeast has among the lowest rates of projected future warming

compared to other regions of the US. Winter minimum temperatures

show the greatest change,with projected increases ranging from 4-5°F (2-3°C)

to as much as 9°F (5°C) by 2100,with the largest increases in coastal regions.

Maximum temperatures are likely to increase much less than minimums, again,

with the largest changes in winter. Model scenarios offer a range of potential

future changes for precipitation,from roughly 25% increases by 2100,to little

change or small regional decreases. The variability in precipitation in the

coastal areas of the Northeast is projected to increase. Models provide contrasting scenarios for changes in the frequency and intensity of winter storms.

T

+15oF

+10oF

+5oF

0o

-5oF

+15oF

+10oF

+5oF

0o

-5oF

The view of Mount Washington in New

Hampshire changes dramatically between a

clear day (top photo) and a day when temperatures exceeding 90 ̊F exacerbate air quality

problems across the region.

1

2

3

4
Increase in Weather Extremes

he Northeast is prone to natural

weather extremes and disasters

including ice storms,severe flooding,

nor’easters,hurricanes,and severe or

persistent drought. The ice storm of

January 1998,with extensive tree

damage and an extended period of

power failure,the severe flooding

associated with tropical depression

Floyd in 1999,and six significant

droughts over the last 20 years amply

demonstrate the importance of

weather extremes to the region.

Climate change is likely to decrease

the number of some types of weather

extremes,while increasing others.

The warming projected by climate

models over the next several decades

suggests possible increases in rain

events over frozen ground or rapid

snow melting events that can

increase flooding. Over the coming

century, winter snowfalls and periods

of extreme cold will likely decrease.

In contrast,heavy precipitation

events have been increasing and

warming is likely to continue this

trend. Potential changes in the intensity and frequency of hurricanes are a

major concern.

Adaptations: Possible strategies

include relocating or elevating structures that are at risk from severe

weather and flooding,though this

may not be practical in many cases.

Enhanced design of critical infrastructure (such as power supply) may

improve the likelihood of continuous

operation during extreme weather

events. The complex institutional

framework of community, municipal,

county, regional,and statewide formal

and informal governing bodies and

infrastructure of the Northeast have

the potential to limit the region's ability to respond to extreme events.

Although there are signs of innovative management strategies,the ability of the Northeast to adapt to

extreme situations will depend upon

the ability of institutions to identify

and prioritize vulnerable facilities and

populations. The large differences in

economic status and the aging of the

population in the Northeast are also

likely to be associated with differential impacts based on the ability to

respond to climate change. Where

impacts are significant, climate

change is likely to have greater

impact on lower-income residents,

the elderly, children,and the ill (such

as those with chronic respiratory ailments).

Stresses on Estuaries, Bays, 

and Wetlands

he estuaries,bays,and wetlands

of the Northeast coastal zone

are highly valued as unique ecosystems,major recreational sites,migratory waterfowl habitats,and fishery

sources. The largest US estuary is the

Chesapeake Bay. The bay is heavily

stressed by air and water pollution

from industry, agriculture,and cities.

Farm and urban runoff carries particles,as well as fertilizer and other

excess nutrients into the Bay. These

pollutants initiate processes that

reduce oxygen levels in the water.

Climate change is likely to exacerbate

these stresses by increasing water

temperature.Changes in precipitation

42

NORTHEAST KEY ISSUES

T

T

The photo shows a car which has been

buried in heavy snow. It is possible that over

the next few decades, the effects of warming

will be counter-intuitive. If Lake Erie and

Lake Ontario have shorter seasons of ice

cover, it is possible that lake effect snows in

cities like Cleveland and Buffalo will increase

during mid-winter. Later in the 21st century,

snowfall will likely decrease with the greater

warming.

The estuaries of the mid-Atlantic region include the Chesapeake and Delaware Bays. These

estuaries are geographically fixed, and so, unlike plant and animal species, they cannot move

in response to climate change.
and runoff, much more uncertain elements of the climate scenarios,also

affect coastal salinity. Both temperature and salinity have significant

effects on fish populations,and

human and ecosystem health. Sealevel rise is very likely to substantially

increase wetland and marsh loss.

Climate change impacts are therefore

very likely to compound the many

other stresses on the bays and estuaries of the Northeast.

Adaptations: Strategies include measures to reduce the flow of excess

nutrients into the bay from industrial,

urban,and rural non-point sources,

reduce atmospheric deposition,and

better enforce existing wetland policies. The overall reduction of stresses

from other sources could help to

enhance the resiliency of coastal

ecosystems to additional and sometimes uncertain stresses from climate

variability and change.In addition,

acquisition of lands contiguous to

coastal wetlands could allow for their

inland migration as sea level rises.

43

Winter Minimum Temperature

Percent Salinity Change in the Chesapeake Bay

Canadian Model Hadley Model

Winter minimum temperatures,

important for ski areas to maintain snowpack, warm substantially in both scenarios. Over much

of the eastern seaboard, minimum temperatures increase by

4 ̊F in the Hadley scenario and by

more than 5 ̊F in the Canadian

scenario.

+15oF

+10oF

+5oF

0o

-5oF

July Heat Index Change - 21st Century

Canadian Model Hadley Model

Summer heat index is expected

to increase; the Hadley scenario

shows greater than 3-5 ̊F

increase for much of the eastern

seaboard while the Canadian

scenario shows increases from

8 ̊F to more than 10 ̊F.

+25oF

+20oF

+15oF

+10o

+5oF

0o

The Hadley (top) and Canadian (bottom) climate scenarios each yield

a very different salinity for the Chesapeake Bay based on water balance calculations for the region extending from the upper reaches of

the Bay (39.66N latitude) to the Lower Chesapeake near its opening

to the Atlantic. Salinity has a significant impact on populations of

fish and other organisms.

Winter minimum temperatures show the

greatest change, with

projected increases

ranging from 4-5°F (2-

3°C) to as much as 9°F

(5°C) by 2100.

39.66N Latitude 36.95N

39.66N Latitude 36.95N
Multiple Stresses on 

Urban Areas

limate change will very likely

intersect with many existing

stresses (some climate-related and

some not) on the major urban areas

of the Northeast,with implications

for the overall quality of life. The

infrastructure of many major

Northeast cities (such as water supply, communication,energy delivery,

and waste disposal) is characterized

by aging,insufficient capacity, and

deferred maintenance. Other existing

stresses include crime, chronic airquality problems,and inadequate

power supply to meet peak energy

demands. Decreased snowfalls and

more moderate winter temperatures

are likely to result in decreased winter stresses. However, climate change

has greater potential to add to existing stresses. Major potential consequences of climate change include

the impacts of rising sea level and

elevated storm surges on transportation systems,increased heat-related

illness and death associated with temperature extremes,increased groundlevel ozone pollution associated with

warming,and the impact of precipitation and evaporation changes on relatively inflexible water supply systems.

Adaptations: Strategies include

changing water supply management;

replacing aging infrastructure with

more climate-resilient systems;

strengthening water quality and air

quality controls to minimize the compounding of climate impacts;and

using early warning systems and

measures such as changing roofing

colors and adding shade trees to limit

urban heat that can contribute to

heat-related stresses and deaths.

Recreation Shifts

ncreased warmth and changes in

the seasonal characteristics of

precipitation are likely to have substantial impacts on recreation in the

Northeast. Typical summer recreational activities involving beaches or

freshwater reservoirs are likely to

have extended seasons,with the

region’s diverse waterways becoming

havens for escape from increasing

summer heat. Possible negative

impacts include limiting the ability of

ski areas to maintain snow pack, muting of fall foliage colors,increases in

insect populations,and worsening

ground-level ozone pollution problems, even in the mountains of New

England. Higher sea level coupled

with even moderate storms will probably result in loss of beachfront property.

Adaptations: Strategies

will reflect a regional shift

in recreational activity as

people make trade-offs in

terms of the type,location,

and season of their activities.

44

NORTHEAST KEY ISSUES

Warmer winters are likely to

limit the viability of snow skiing in the Northeast. 

C

I

Milder winters contribute to a higher survival rate for deer and

mice, both of which

are factors in the population of the deer

tick, the primary Lyme

disease vector.

Recent examples of

outbreaks of West

Nile Virus and equine

encephalitis in northeastern urban areas

have substantially

raised concerns about

vector-borne 

diseases.
Human Health

opulations of infectious disease

vectors are often influenced by

climate. Altered mosquito populations and Lyme disease vectors are

possible changes in response to higher temperatures (particularly the

milder winters projected by virtually

all climate models) and changes in

moisture. Milder winters contribute

to a higher survival rate for deer and

mice,both of which are factors in the

population of the deer tick,the primary Lyme disease vector. However,

the complexity of the relationships

makes changes in the distribution

and frequency of the disease under

altered climate difficult to predict.

While warmer and wetter conditions

may alter insect vector survival,

research is lacking on how these

changes may influence disease occurrence. The recent examples of outbreaks of West Nile Virus and equine

encephalitis in northeastern urban

areas have substantially raised concerns about vector-borne diseases

and illustrate that improved monitoring and better understanding of these

diseases are relevant for the region.

Increased rainfall and flooding,if

severe,creates conditions for possible

public and private water source contamination (such as with

Cryptosporidium). However, in large

measure,US public health infrastructure and response capabilities,if vigorously sustained,are likely to limit

many potential impacts.

Species Changes

hanges in species composition

are often associated with

changes in temperature and precipitation. Key concerns involve the

potential for changes in predator-prey

relationships, changes in pest types

and populations,invasive species,and

in key species that are truly characteristic of a region or are of economic significance. For example,lobster

populations are associated with cooler waters and warming is thus likely

to promote northward migration of

the lobster population – a key issue

for New England. Coastal population

pressures combined with sea-level

rise are very likely to reduce habitat

for migratory birds along the Atlantic

Flyway. Warming is also likely to substantially limit trout populations – a

key issue for Pennsylvania. Changes

in species mix and introduction of

climate-driven invasive species are

likely to also induce unanticipated

feedbacks on ecosystems.

The likely migration of sugar maple

trees northward into Canada as climate warms would sharply reduce

maple syrup production,a cultural

tradition in the Northeast.

45

The diverse waterways and extensive forests

of the Northeast are likely to have more warm

weather recreational use.

The maps above show current and projected forest types for the Northeast, based on the DISTRIBmodel (see Forest sector).

Note that Maple-Beech-Birch, currently a dominant forest type in the region, is completely displaced by other forest types in both

the Hadley and Canadian climate scenarios.

C

P

Lobster populations are

associated with cooler

waters and warming is thus

likely to promote northward

migration of the lobster

population – a key issue for

New England. 

Dominant Forest Types

Current - 

1960-1990

Hadley Scenario - 

2070-2100

Canadian Scenario - 

2070-2100

White-Red-Jack Pine

Spruce-Fir

Longleaf-Slash Pine

Loblolly-Shortleaf Pine

Oak-Pine

Oak-Hickory

Oak-Gum-Cypress

Elm-Ash-Cottonwood

Maple-Beech-Birch

Aspen-Birch

No Data