Sea level rise threatens salt marshes like Scarborough Marsh, which is Maine's
largest. Credit: Robert Pos, U.S. Fish and Wildlife Service.
Changing the climate threatens ecosystems by disrupting
relationships between species. Wildflowers and woody perennials
are blooming—and migratory birds are arriving—sooner in spring.
Not all species adjust in the same way, however, so the food that
one species needs may no longer be available when that species
arrives on its migration. Warmer temperatures allow deer
populations to increase, leading to a loss of forest underbrush,
which makes some animals more vulnerable to predators.
Climate change can allow invasive species to expand their ranges.
For example, the hemlock woolly adelgid has recently infested
hemlock trees near the coast in southern Maine. Infestation even-
tually kills almost all hemlock trees, which are replaced by black
oaks, black birch, and other hardwoods. Warmer temperatures
are likely to enable the woolly adelgid to expand inland and up the
coast. The loss of hemlock trees would remove the primary habitat
for the blue-headed vireo and Blackburnian warbler. It could also
cause streams to run dry or become excessively warm more often,
harming brook trout and brown trout.
Fishing and Farms
Parts of Maine's fishing and agriculture sectors may suffer as the
climate changes. Rising water temperatures can lower oxygen
levels and otherwise alter freshwater and marine ecosystems.
Lobsters and other shellfish are vulnerable to increased ocean
acidity, especially during eariy life stages when acidity impairs their
ability to build shells. As ocean temperatures rise, some fish species
are moving northward or into deeper waters to remain within their
normal temperature range. The loss of coastal wetlands could harm
clams, bass, and other commercially important fish.
Climate change may also pose challenges for agriculture. Some
farms may be harmed if more hot days and droughts reduce crop
yields, or if more flooding and wetter springs delay their planting
dates. Other farms may benefit from a longer growing season and
the fertilizing effect of carbon dioxide. Rising temperatures may also
affect maple syrup production, but the likely impact over the next
few decades is unknown.
Human Health
Climate change is likely to amplify some of the existing threats to
health in Maine. Certain people are especially vulnerable, including
children, the elderly, the sick, and the poor.
Warmer weather could increase the incidence of some diseases
carried by insects and some respiratory conditions. The ticks that
transmit Lyme disease are active when temperatures are above
45°F, so warmer winters could lengthen the season during which
ticks can become infected or people can be exposed to the ticks.
Higher temperatures can also increase the formation of ground-
level ozone (smog), a pollutant that can contribute to respiratory
problems such as asthma. Finally, rising temperatures may increase
the length and severity of the pollen season for plants such as
ragweed, which has already been observed in other regions.
Increase in Lyme disease between 1996 and 2013. Each dark dot shows one
case reported in 1996; light dots show 2013. The increased range shown here
has been attributed to factors other than climate change. Nevertheless, additional
warming will lengthen the season during which people are exposed to Lyme
disease and may allow the disease to spread to colder areas. Source: CDC.
Winter Recreation
Warmer winters may bring more rain and less snow to Maine. A
decline in snowfall would shorten the season during which the
ground is covered with snow, which could harm recreational
industries like skiing, snowboarding, and snowmobiling, and the
local economies that depend on them.
The sources of information about climate and the impacts of climate change in this publication are: the national climate assessments by the U.S. Global Change Research
Program, synthesis and assessment products by the U.S. Climate Change Science Program, assessment reports by the Intergovernmental Panel on Climate Change, and EPA's
Climate Change Indicators in the United States. Mention of a particular season, location, species, or any other aspect of an impact does not imply anything about the likelihood or
importance of aspects that are not mentioned. For more information about climate change science, impacts, responses, and what you can do, visit EPA's Climate Change website
at www.epa.aov/climatechanae.