Transcript Climate Change PowerPoint

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A presentation developed by the National Academy of Sciences based on its report
Ecological Impacts of Climate Change (2009): www.nas.edu/climatechange.
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The Climate is Changing
•
•
•
•
Temperatures are rising
Sea levels are rising
The ocean is acidifying
Climate change is reflected
in water cycle changes and
in extreme weather
Temperature rise, indicated by color
(red=higher rate of increase). Earth’s surface
temperature has risen ~1.3˚ F since 1850.
Image courtesy of the Joint Institute for the Study of the
Atmosphere & Ocean, U. of Washington.
Ecological Impacts
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Living things are intimately connected to their
physical surroundings.
Ecosystems are affected by changes in:
– temperature
– rainfall/moisture
– pH
– salinity (saltiness)
– activities & distribution of other species
– …many other factors
Ecological Impacts
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As a result of climate change, species and
ecosystems are experiencing changes in:
–
–
–
–
ranges
timing of biological activity
growth rates
relative abundance of species
– cycling of water and nutrients
– the risk of disturbance from
fire, insects, and invasive
species
Ecological Impacts
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• As a result of climate change, species and
ecosystems are experiencing changes in:
–
–
–
–
ranges
timing of biological activity
growth rates
relative abundance of species
– cycling of water and nutrients
– the risk of disturbance from
fire, insects, and invasive
species
Range Shifts
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Species are relocating to areas
with more tolerable climate
conditions.
Range shifts particularly
threaten species that:
– cannot move fast enough
– depend on conditions that are
becoming more rare (like sea ice)
Plant hardiness zone maps, 1990 and
2006. Most zones shifted northward in
this period.
Map courtesy of the National Arbor Day Foundation.
Ecological Impacts
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As a result of climate change, species and
ecosystems are experiencing changes in:
–
–
–
–
ranges
timing of biological activity
growth rates
relative abundance of species
– cycling of water and nutrients
– the risk of disturbance from
fire, insects, and invasive
species
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Timing of Biological Activity
Some seasonal biological
activities are happening
15-20 days earlier than
several decades ago:
– Trees blooming earlier
– Migrating birds arriving earlier
– Butterflies emerging earlier
Changes in timing differ from
species to species, so
ecological interactions are
disrupted.
European pied
flycatcher chicks are
now born later than the
caterpillars they eat.
Images used under the
terms of the GNU Free
Documentation License.
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Global Changes, Local Impacts
Although climate change is global, the
ecological impacts are often local.
What’s happening in your backyard?
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Impacts in the Pacific Coastline
Shifting Ranges of Checkerspot Butterflies
• Edith’s checkerspot: range has shifted northward and to higher
elevations over 40+ years
• Quino checkerspot: first endangered species for which climate
change is officially listed as a threat and as a factor in the plan for its
recovery
Image courtesy of Dr. Gordon Pratt, www.quinocheckerspot.com.
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Impacts in the Pacific Coastline
Changes in the Water
• Shift in species ranges: many
species moving northward
• Mysterious dead zones along
Washington and Oregon coastline:
cause undetermined but potential
links to climate change
Scientists retrieve a water sample for
research on a recurring “dead zone”
off the coasts of Washington and
Oregon.
Image courtesy of Oregon State University.
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Impacts in the Pacific Coastline
California Wine Industry: Unwelcome Changes?
• Climate change affects managed ecosystems like vineyards and
farms just as it affects natural ecosystems
• Future warming unlikely to help wine growers in California’s
premium wine regions: some areas projected to become “marginal”
by 2100
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Impacts in Alaska and the Arctic
Effects on Ice-Dependent Animals
• Year-round sea ice shrinking: walruses and other animals
challenged to find platforms for nursing and resting
• Polar bears facing difficult hunting conditions: seals now surfacing in
open ocean instead of holes in ice
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Impacts in Alaska and the Arctic
Changing Food Chains
• Increased shrub growth presenting
a threat to caribou (wild reindeer)
– Shrubs crowding out lichens (a key
winter food for caribou)
– Shrubs collect snow, causing deep
snowdrifts: deep snow makes it
hard for caribou to reach lichens
hidden beneath
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Impacts in Alaska and the Arctic
Feedback Loops: Arctic Warming Faster
• The Arctic is warming twice as fast as the rest of the planet
– As sea ice and seasonal snow cover melts, previously reflective white
surfaces converted to darker surfaces (to ocean water or vegetation)
– Thawing permafrost releases carbon dioxide and methane into the
atmosphere, increasing greenhouse gases
Rate of warming,
indicated by colors
(red=higher rate).
Image created with data from the Goddard Institute for Space Studies.
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Impacts in Western Mountains
Wildfire, Drought, and Insects: Complex Interactions
Climate change increases the risk of fire in areas where decades of total
fire suppression have resulted in buildup of dead fuels.
Wildfire increasing in frequency, size, season length:
– Longer, more intense summer droughts stressing trees
– Stressed trees are more susceptible to attacking beetles, which leave
standing dead fuels in their wake
A wildfire in Bitterroot National
Forest, Montana.
Image courtesy of John McColgan, USDA Forest Service.
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Impacts in Western Mountains
Effects on The American Pika
• Climbing to higher elevations in response
to warming
• Many populations now isolated on
“mountaintop islands”
Pika images courtesy of J. R. Douglass, Yellowstone
National Park; Aerial image courtesy NASA.
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Impacts in Western Mountains
Changes in Trout Habitat
• Earlier springs, warmer summers reducing stream flows as
mountain snow melts off earlier in the season
• Some streams reaching temperatures lethal to trout (>78˚F)
Image courtesy USGS.
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Impacts in Southwestern Deserts
Wildfire and Invasive Species
• Nonnative grasses becoming
established in deserts:
– Red brome (in the Mojave)
– Buffelgrass (in the Sonoran)
• Grasses transform desert into
flammable grassland: fire-adapted
grasses re-establish quickly, pushing
out native species like Saguaro cactus
• Spread of grasses not directly a result
of climate change, but warming may
allow them to further spread in the
desert and extend to higher
elevations.
Image courtesy T. Esque, USGS.
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Impacts in Southwestern Deserts
The Piñon Pine: Past a Tipping Point
• Drought in 2000-2003 stressed a large swath of piñons, leaving
them susceptible to infestation by pine bark beetles
• This example shows how a stressful event can trigger dramatic
ecological change when an ecosystem is subject to many interacting
stresses
2002
2004
Images courtesy D. Allen, USGS.
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Impacts in the Central U.S.
Agricultural Impacts
• Difficult to pinpoint climate impacts:
climate change occurring along with
improvements in farming techniques
• In general, plants may:
– Grow faster (increasing yields unless it
becomes too warm or crops mature too
early)
– Be affected by carbon dioxide levels
(increased growth for some plants, not for
others)
• Good information about changes and
adaptive practices is essential for farmers
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Impacts in the Central U.S.
Migratory Waterways: Drying Up?
• “Playa lakes” or “Prairie potholes” essential for migrating birds:
used for resting, feeding, and mating
• Climate change, combined with other pressures (irrigation demands,
pollution, etc.), may dry up these important waterways
Image courtesy of the U.S. Fish and Wildlife Service.
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Impacts in the Southeast
Challenges to Everglades Restoration
Everglades has shrunk due to human manipulation of the region’s
water; ongoing efforts aim to restore the ecosystem.
• Climate change impacts (increasing water temperature, changes in
precipitation) may make restoration efforts more difficult
1850
Today
Images courtesy Rodney Cammauf, National Park Service (panther); South Florida Water Management District (maps)
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Impacts in the Southeast
Sea-level Rise
• Fragments barrier islands, reconfigures
shorelines
• May leave certain ecosystems struggling
to adapt—in particular those adapted to
the conditions between land and sea
• Landward movement of mangroves and
marshes may be inhibited by human
development
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Impacts in the Southeast
Coral Reefs: Multiple Changes
• Climate change is compounding other
factors affecting reefs (coastal
development, pollution, overfishing)
• Heat stress causes coral bleaching: corals
expel symbiotic algae, leaving white
“bones” behind (deadly to coral if longlasting)
• Ocean acidification affects marine
organisms’ ability to build shells and
skeletons: likely to slow or stop the growth
of coral by 2100
Coral bleaching
Image courtesy of NOAA.
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Impacts in the Southeast
Northward Movement of Tropical Species
• Bird and butterfly watchers across the Southeast looking out for new
species; some former seasonal migrants now staying year-round
The rufous hummingbird
has become a yearround resident in
Alabama.
Image courtesy Dean E. Briggins,
U.S. Fish and Wildlife Service.
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Impacts in the Northeast
Fisheries
• Cod: affected by water temperature
– Habitat may become restricted to cooler
pockets (<54˚F for adults, <46˚F for young)
• Lobsters: affected by oxygen levels
– Warmer water holds less oxygen: oxygen
becomes insufficient for lobsters >79˚F
– In north, warming may improve lobster habitat
• Oysters: Deadly parasite Perkinsus marinus
moving northward
– Range expanded from Chesapeake Bay to
Maine: shift linked to above-average winter
temperatures
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The Role of Human Beings
Causes of Climate Change
• It is very likely that most of the
climate change in the current era is
the result of human activities.
– Human activities have increased
concentrations of greenhouse gases
in the atmosphere.
– These gases trap heat and cause
the Earth to warm.
Figure adapted from Climate Change 2007: The Physical
Science Basis. Working Group 1 Contribution to the 4th
Assessment Report of the Intergovernmental Panel on Climate
Change. Figure SPM.5. Cambridge University Press.
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The Role of Human Beings
Rate of Climate Change
• Climate change in the current era is expected to be extremely rapid
compared to transitions in and out of past ice ages.
• Ecosystems are more vulnerable to changes that happen rapidly.
A scientist holding an ice
core—a sample taken
from polar ice caps or
mountain glaciers.
Ice cores reveal clues
about climate changes in
Earth’s past.
Image courtesy USGS National Ice Core Laboratory.
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The Role of Human Beings
Compounding Factors
• Human activities have many other effects on ecosystems.
• These effects compound the effects of climate change, making it
more difficult for ecosystems to adapt.
– Pollution
– Habitat fragmentation
– Invasive species
– Overfishing
– Manipulation of water sources
– …and much more