Climate change effects speeding up
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December 21, 2012 |
Plant and animal species are shifting their
geographic ranges and the timing of their life
events – such as flowering, laying eggs or
migrating – at faster rates than researchers
documented just a few years ago, according to a
technical report on biodiversity and ecosystems
used as scientific input for the 2013 Third
National Climate Assessment.
The report, Impacts of Climate Change on
Biodiversity, Ecosystems, and Ecosystem
Services,
http://downloads.usgcrp.gov/NCA/Activities/Biodiversity-Ecosystems-and-Ecosystem-Services-Technical-Input.pdf,
synthesizes the scientific understanding of the
way climate change is affecting ecosystems,
ecosystem services and the diversity of species,
as well as what strategies might be used by
natural resource practitioners to decrease
current and future risks.
More than 60 federal, academic and other
scientists, including the lead authors from the
U.S. Geological Survey, the National Wildlife
Federation and Arizona State University in
Tempe, authored the assessment.
"These geographic range and timing changes are
causing cascading effects that extend through
ecosystems, bringing together species that
haven't previously interacted and creating
mismatches between animals and their food
sources," said Nancy Grimm, a scientist at ASU
and a lead author of the report.
Grimm explained that such mismatches in the
availability and timing of natural resources can
influence species' survival; for example, if
insects emerge well before the arrival of
migrating birds that rely on them for food, it
can adversely affect bird populations. Earlier
thaw and shorter winters can extend growing
seasons for insect pests such as bark beetles,
having devastating consequences for the way
ecosystems are structured and function. This can
substantially alter the benefits people derive
from ecosystems, such as clean water, wood
products and food.
"The impact of climate change on ecosystems has
important implications for people and
communities," said Amanda Staudt, a NWF climate
scientist and a lead author on the report.
"Shifting climate conditions are affecting
valuable ecosystem services, such as the role
that coastal habitats play in dampening storm
surge or the ability of our forests to provide
timber and help filter our drinking water."
Another key finding is the mounting evidence
that population declines and increased
extinction risks for some plant and animal
species can be directly attributed to climate
change.
The most vulnerable species are those already
degraded by other human-caused stressors such as
pollution or exploitation, unable to shift their
geographic range or timing of key life events,
or that have narrow environmental or ecological
tolerance.
For example, species that must live at high
altitudes or live in cold water with a narrow
temperature range, such as salmon, face an even
greater risk due to climate change.
"The report clearly indicates that as climate
change continues to impact ecological systems, a
net loss of global species’ diversity, as well
as major shifts in the provision of ecosystem
services, are quite likely," said Michelle
Staudinger, a lead author of the report and a
USGS and University of Missouri scientist.
For example, she added, climate change is
already causing shifts in the abundance and
geographic range of economically important
marine fish. "These changes will almost
certainly continue, resulting in some local
fisheries declining or disappearing while others
may grow and become more valuable if fishing
communities can find socially and economically
viable ways to adapt to these changes."
Natural resource managers are already contending
with what climate change means for the way they
approach conservation. For example, the report
stated, land managers are now more focused on
the connectivity of protected habitats, which
can improve a species’ ability to shift its
geographic range to follow optimal conditions
for survival.
"The conservation community is grappling with
how we manage our natural resources in the face
of climate change, so that we can help our
ecosystems to continue meeting the needs of both
people and wildlife," said Bruce Stein, a lead
author of the report and director of climate
adaptation at for the NWF.
Other key findings of the report include:
-- Changes in precipitation and extreme weather
events can overwhelm the ability of natural
systems to reduce or prevent harm to people from
these events. For example, more frequent heavy
rainfall events increase the movement of
nutrients and pollutants to downstream
ecosystems, likely resulting not only in
ecosystem change, but also in adverse changes in
the quality of drinking water and a greater risk
of waterborne-disease outbreaks.
-- Changes in winter have big and surprising
effects on ecosystems and their services.
Changes in soil freezing, snow cover and air
temperature affect the ability of ecosystems to
store carbon, which, in turn, influences
agricultural and forest production. Seasonally
snow-covered regions are especially susceptible
to climate change because small precipitation or
temperature shifts can cause large ecosystem
changes. Longer growing seasons and warmer
winters are already increasing the likelihood of
pest outbreaks, leading to tree mortality and
more intense, extensive fires. Decreased or
unreliable snowfall for winter sports and
recreation will likely cause high future
economic losses.
-- The ecosystem services provided by coastal
habitats are especially vulnerable to sea-level
rise and more severe storms. The Atlantic and
Gulf of Mexico coasts are most vulnerable to the
loss of coastal protection services provided by
wetlands and coral reefs. Along the Pacific
coast, long-term dune erosion caused by
increasing wave heights is projected to cause
problems for communities and for recreational
beach activities. However, other kinds of
recreation will probably improve due to better
weather, with the net effect being that visitors
and tourism dollars will shift away from some
communities in favor of others.
-- Climate change adaptation strategies are
vital for the conservation of diverse species
and effective natural resource policy and
management. As more adaptive management
approaches are developed, resource managers can
enhance the country’s ability to respond to the
impacts of climate change through
forward-looking and climate science-informed
goals and actions.
-- Ecological monitoring needs to be improved
and better coordinated among federal and state
agencies to ensure the impacts of climate change
are adequately monitored and to support
ecological research, management, assessment and
policy. Existing tracking networks in the United
States will need to improve coverage through
time and in geographic area to detect and track
climate-induced shifts in ecosystems and
species.
Federal law requires that the U.S. Global Change
Research Program submit an assessment of climate
change and its impacts to the president and the
Congress once every four years.
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