Transcript global warming

Anthropogenic Sources of
Climate Change
(Global Warming)
Chapter 23
APES
Anthropogenic Sources of Climate
Change
• Two main causes
1. Deforestation
2. Increasing Greenhouse Gas levels
• Burning Fossil Fuels
• Main villain is currently CO2
Deforestation
Deforestation - US
• About one half of
the forests that
covered the Earth
are gone
• Since 1600, 90%
of the U.S. forests
have been cleared
away
Results of
Deforestation
• Loss of trees’ ability to remove CO2
• Decaying trees release CO2 and
methane
– 25% of global GHG emissions
• Fallen trees are often burned which
releases CO2
– Accounts for 20% of global CO2 emissions
• Deforestation the largest source of
emissions in developing countries
Greenhouse
Effect
Greenhouse Effect
• Certain gases in the Earth’s
atmosphere trap energy from the sun
– carbon dioxide
– methane
– water vapor
– nitrous oxide
• Without these gases, the Earth’s
average temperature would be about
60ºF colder
• These gases are Greenhouse Gases
Global
Warming
Evidence of Global
Warming
• CO2 and Temperature
Mauna Loa Study
• Study air chemistry in
remote location in Hawaii
from 1950’s to present
• Showed annual
fluctuations in CO2 btwn
winter & summer (why it
looks like a zig-zag)
• Also a steady CO2
increase from 315 ppm
by volume in 1958 to 370
ppm in 1999.
• This graph has been on
almost every APES test!!!
Five Warmest Years on
Record
1.
2.
3.
4.
5.
2005
1998
2002
2003
2004
Since 1980, the Earth has experienced 19 of its
20 hottest years on record
Evidence
• CO2 and Temperature
• Glaciers
Glaciers
• Have been shrinking throughout the
20th Century
• Loss of glaciers in South America and
Asia is particularly rapid and will
threaten the water supplies of millions
of people
• http://www.cnn.com/2007/TECH/science/1
1/26/andes.water.ap/index.html
Evidence
• CO2 and Temperature
• Glaciers
• Polar Ice
– Arctic
– Antarctic
– Greenland
Arctic Ice
Arctic Ice
• Perennial ice may be 10 or more feet thick
• New ice is only one to seven feet thick
• Since 1970  10% loss of ice cover per decade
Albedo Effect
NASA Sees Rapid Changes
in Arctic Sea Ice
NEWS RELEASE: September 13, 2006
• From 1970 until 2000 there was a 10
percent decrease in Arctic perennial
sea ice every decade
• Between 2004 and 2005 the ice
shrunk abruptly by 14 percent
Permafrost
Permafrost
• Where soil over 1-meter down never thaws
• About 10% of Earth’s surface has permafrost
• Tundra and taiga are characterized by extreme
cold
– 24 hours of sun during the summer
– Huge amount of vegetation grows
• In the last 11,000 years, the permafrost has not
thawed
– None of the vegetation has decayed
– Decay releases CO2 and methane
Permafrost
• Alaska permafrost
temperature has
increased 0.5° to 1.5° C
since 1980,
• Serious effects include
– sinking roads and buildings
– eroding tundra riverbanks
– changes in tundra
vegetation
– increased carbon dioxide
and methane emissions
from thawed peat.
Permafrost
• Estimates of billions
of tons of methane
– Will double existing
methane in
atmosphere
• Methane is 20 to 60
times as strong of a
greenhouse gas as
CO2
Antarctic Ice
Antartica
• Land mass
covered by
multiple glaciers
• Glaciers average
8000 feet thick
• Represents 10%
of all landmass
on Earth
Moulins
• Rivers of water about 10
meters in diameter that
flow through the glacier
• Bring melted water
below the glaciers
• Can cause glaciers to
slip off bedrock into
ocean
Series of
Moulins
Antarctica Melting
If all of the ice in the
glaciers of Antarctica melt
the oceans will rise
200 feet
Greenland Ice
Greenland Ice
Melt
• Glaciers located on
three islands
• Greenland loses 20%
more ice than it gains
each year
• If all of the ice melts –
oceans will rise 23 feet
• If moulins work like
those in Antarctica…
•
http://www.cnn.com/SPECIALS/2007/
planet.in.peril/greenland.html
Evidence
• CO2 and Temperature
• Glaciers
• Polar Ice
– Arctic
– Antarctic
– Greenland
• Weather Severity
Droughts
• The 1999-2002 national drought was one of
the three most extensive droughts in the last
40 years
• In 2002, the Western United States
experienced its second worst wildfire season
in the last 50 years; more than 7 million acres
burned
• The period from April through June of 1998
was the driest three-month period in 104
years in Florida, Texas, and Louisiana
Evidence
• CO2 and Temperature
• Glaciers
• Polar Ice
– Arctic
– Antarctic
– Greenland
• Weather Severity
• Biome Changes
Oceans absorb CO2
• CO2 in water makes
Carbonic Acid
• Increased CO2 especially
in cold water
• As cold deep ocean
currents (abyssal)
resurface they release
CO2
• Greater acidity of oceans
is bleaching coral
Consequences
of Global Climate
Change
Consequence
• Cold Europe
Arctic Water lower
Salinity
Thermohaline
Circulation
• Half Century of measurements by
Britain's National Oceanography
Centre
– Suggest a noticeable slowing (30%)
– Due to Arctic and Greenland ice melting
Consequence
• Cold Europe
• Increased Smog
Consequence
• Cold Europe
• Increased Smog
• Spread of Tropical Diseases
Consequence
• Cold Europe
• Increased Smog
• Spread of Tropical Diseases
• Changes in Biodiversity
Changes in
Biodiversity
"It is not the strongest of the
species that survive, nor the
most intelligent, but the most
responsive to change."
Charles Darwin, 1835
Changes in
Biodiversity
Biomes
Shift of Alpine biomes up mountains and
further North/South
Changes in
Biodiversity
Biomes
Shift of Alpine biomes up mountains and
further North/South
Die-offs
Coral bleaching die-offs of up to 50% in the
Indian Ocean
Dire prediction for
world's coral reefs
POSTED: 1404 GMT (2204 HKT), October 25, 2006
CHARLOTTE AMALIE, U.S. Virgin Islands (AP)
Researchers fear more than half the world's coral
reefs could die in less than 25 years and say
global warming may at least be partly to blame.
Sea temperatures are rising, weakening the reefs' resistance to increased
pollutants, such as runoff from construction sites and toxins from boat paints. The
fragile reefs are hosts to countless marine plants and animals.
"Think of it as a high school chemistry class," said Billy Causey, the Caribbean and Gulf Mexico director of the National Oceanic and Atmospheric
Administration.
"You mix some chemicals together and nothing happens. You crank up the Bunsen burner and all of a sudden things start bubbling around. That's
what's happening. That global Bunsen burner is cranking up."
Causey was one of some 200 private and government researchers from the Caribbean, Florida and U.S. Pacific islands who gathered in St. Thomas
for a meeting of the NOAA's U.S. Coral Reef Task Force.
Last year's coral loss in the Caribbean waters supports predictions that 60 percent of the world's coral could die within a quarter century, said Tyler
Smith of the University of the Virgin Islands.
"Given current rates of degradation of reef habitats, this is a plausible prediction," Smith said.
More than 47 percent of the coral in underwater study sites covering 31 acres around the U.S. Virgin Islands died after sea temperatures exceeded the
norm for three months in 2005, said Jeff Miller, a scientist with the Virgin Islands National Park.
The unusual warm water can stress coral, causing it to lose its pigment and making it more vulnerable to disease.
This year, Caribbean coral narrowly avoided another widespread episode of bleaching when sea temperatures briefly surpassed levels considered
healthy for reefs.
Up to 30 percent of the world's coral reefs have died in the last 50 years, and another 30 percent are severely damaged, said Smith, who studies coral
health in the U.S. Virgin Islands and collaborates with researchers globally.
"U.S. Virgin Islands coral today is likely at its lowest levels in recorded history," Smith said.
The researchers said global warming was a potential cause of the abnormally high sea temperatures but was not the only suspect in the reefs' demise.
What causes disease in coral can be hard to pinpoint and could be a combination of things. Other threats include silt runoff from construction sites,
which prevents the coral from getting enough sunlight, and a record increase in fleshy, green algae, which competes with coral for sunlight.
"Climate change is an important factor that is influencing coral reefs worldwide," said Mark Eakin, director of NOAA's Coral Reef Watch. "It adds to the
other problems that we are having."
Changes in
Biodiversity
Biomes
Shift of Alpine biomes up mountains and
further North/South
Die-offs
Coral bleaching die-offs of up to 50% in the
Indian Ocean
Extinctions
Golden Toads, Harlequin Frogs, ...
Global Warming Already Causing
Extinctions, Scientists Say
Hannah Hoag for National Geographic News November 28, 2006
• In Costa Rica about two-thirds of the 110
known harlequin frog species are extinct
• In Antarctica, the Adélie penguin on
Litchfield Island has disappeared.
Changes in
Biodiversity
Biomes
Shift of Alpine biomes up mountains and
further North/South
Die-offs
Coral bleaching die-offs of up to 50% in the
Indian Ocean
Extinctions
Golden Toads, Harlequin Frogs, ...
Life Cycles
Gothic marmots emerge from hibernation
about a month earlier than 30 years ago
Life Cycle Changes
• Marmots in the area now emerge from
hibernation about a month earlier than they
did 30 years ago
• During the same period, the average April
low temperature in Crested Butte rose 5.9
degrees
Changes in
Biodiversity
Biomes
Shift of Alpine biomes up mountains and
further North/South
Die-offs
Coral bleaching die-offs of up to 50% in the
Indian Ocean
Extinctions
Golden Toads, Harlequin Frogs, ...
Life Cycles
Gothic marmots emerge from hibernation
about a month earlier than 30 years ago
Physiology
The average weight of adult female polar
bears has decreased by more than 20%
over the last 25 years
Global Warming Already
Causing Extinctions,
Scientists Say
Hannah Hoag for National Geographic News November 28, 2006
• Polar bears depend on
ice
• Without the ice, the
polar bear will die
Changes in
Biodiversity
Biomes
Shift of Alpine biomes up mountains and
further North/South
Die-offs
Coral bleaching die-offs of up to 50% in the
Indian Ocean
Extinctions
Golden Toads, Harlequin Frogs, ...
Life Cycles
Gothic marmots emerge from hibernation
about a month earlier than 30 years ago
Physiology
The average weight of adult female polar
bears has decreased by more than 20%
over the last 25 years
Migration
Multiple areas affected
Migratory Species as
Indicators
• Effects of climate change on the
behaviour on migratory species are
becoming increasingly evident.
• Although migration is itself a flexible
reaction to ecological conditions,
migratory species seem more
vulnerable than most wildlife as they
use multiple habitats and sites and a
wide range of resources through their
migratory cycle.
• www.cms.int/news/current_news_page.htm
Routes farther North & Wind Barriers
European Bee-Eaters (Merops apiaster) once very
rare in Germany are now breeding regularly across
the country.
The Rosy-Breasted Trumpeter Finch (Rhodopechys
githaginea) is one of many birds once normally confined
to arid North Africa and the Middle East now found in
increasingly large numbers in southern Spain.
Bewick’s Swan
The arrival of hundreds of Bewick Swans (Cygnus
columbianus) flying in distinctive “V” formations used to
herald the arrival of the British winter; ornithologists now
report numbers down to double figures.
Habitat Changes
Alien species like the Pacific Oyster brought to Europe for
commercial reasons used not to be able to survive outside
artificial pens. As the North Sea has grown warmer, the
Pacific oyster has been able to breed in the wild and is
now displacing native oysters in the Wadden Sea.
Incidence of flooding and resultant sediment run-off in
Queensland, Australia damaged seagrass pasture leading
to reduced growth and breeding rates for Green turtles
Baffin Bay hosts the largest concentrations of wintering
Narwhals Here the trend has been for increased ice
coverage in winter. The Narwhals depend on cracks in the
ice to breathe and there have been several occasions when
they have become trapped in the ice. Their site fidelity
and the decrease in open water make them susceptible to
Climate Change.
Feeding
As migratory species are affected by climate change, then so
are their prey species. For example, reproductive success of the
non-migratory Great Tit and migratory Pied Flycatcher is
being affected by the changing availability of caterpillar food
supplies. The temporal mismatch of prey and predator is part
of a phenomenon known as “phenological disjunction”.
Reduced oceanic salinity causes shifts in the distribution of
biomass constituents of the food chain with a tendency for
poleward shifts in species assemblages and the potential loss of
some polar specialist species like the Narwhal.
It is doubtful whether Polar Bears will be able to adapt fast
enough to changing ice conditions affecting the habitat of their
seal prey species, and the disappearance of the ice threatens the
bears’ survival.
Feeding
Krill may be outcompeted by other species more tolerant of warmer water with
repercussions for species higher up the food chain
Consequence
•
•
•
•
Cold Europe
Increased Smog
Spread of Tropical Diseases
Changes in Biodiversity
• Droughts and fires
Tuareg & Wodaabe
Herders
Climate change has upset rainfall
patterns and caused severe drought and
desertification in the area
Consequence
•
•
•
•
•
Cold Europe
Increased Smog
Spread of Tropical Diseases
Changes in Biodiversity
Droughts and fires
• Sea levels rise
total melting would raise ocean level 75m
Florida during Ice Age - 20,000 years ago (400 feet below today)
Florida – if West sheet or Greenland melted (17-foot rise)
Florida – if East sheet melted (170-foot/50m rise)
Positive Feedback
Positive Feedback
• Oceans currents and CO2 levels
– Cold deep resurface and emit CO2
– Warmer oceans do not take up CO2 and actually
emit more CO2.
• Permafrost melting
– CO2 and methane released by decomposition
• Arctic ice melting
– Less reflection of sunlight – water and land heat
up
• Desertification
– Soil dries out and releases CO2
Why do WE need to
Reduce?
• Global Warming is a fact
– Natural
– Man-made
– Both????
• China and India will soon surpass
U.S.A. in Greenhouse gas emission
• If we do nothing, they will continue to
do nothing (The Economist 9/9/06)
What can we do?
• Build Green
• Reduce use of electricity from
fossil fuels
• Hydrogen powered vehicles
• Invest in green companies
• Reduce meat consumption
Cattle and Methane
• Cattle and other ruminant animals
–Methane is by-product of digestion
• Organisms in their stomachs break
down fiber in grasses and grains they
eat
Environmental Protection
Agency
Methane Source
2003
Fossil Fuel Production
37.6 %
Cattle
28.3 %
Landfills and
Wastewater Treatment
Other
30.8 %
Total for U.S.
100 %
3.3 %
Methane is 20
to 60 times as
strong of a
greenhouse gas
as CO2
What can we do?
• Build Green
• Reduce use of electricity from
fossil fuels
• Hydrogen powered vehicles
• Invest in green companies
• Reduce meat consumption
• Carbon sequestration
Carbon Sequestration
http://sequestration.mit.edu/technology_overview/index.html
• Two primary types of carbon sequestration.
• Carbon dioxide capture and storage
– carbon dioxide is captured at its source (e.g., power plants, industrial
processes)
– subsequently stored in non-atmospheric reservoirs (e.g., depleted oil and
gas reservoirs, unmineable coal seams, deep saline formations, deep
ocean).
• Enhancing natural processes (e.g., forestation).
• What about seeding the ocean with iron to promote algal
growth which will then absorb CO2 from air? What are the pros
and cons of this? Read articles on Bb to find out!
• [Encyclopedia of Energy (2004)].
Carbon Sequestration
http://sequestration.mit.edu/technology_overview/index.html
The Sleipner project in Norway's North Sea is the world's
first commercial carbon dioxide capture and storage project
Started in 1996, it sequesters about one million metric tons
of carbon dioxide each year
http://www.statoil.com/STATOILCOM/SVG00990.NSF/web/sleipneren?opendocument
What can we do?
• Build Green
• Reduce use of electricity from fossil
fuels
• Hydrogen powered vehicles
• Invest in green companies
• Reduce meat consumption
• Carbon sequestration
• Encourage ratification of Kyoto
Protocol
Cutting Emissions
•
Earth Summit 1992- Rio de Janeiro
–
–
Return greenhouse gas concentrations to 1990
conditions by 2000
Only Fiji ratified this treaty
•
Kyoto Protocol 1997- Kyoto Japan
– 160 countries finally agreed on a
new treaty
– Roll back CO2, methane, &
nitrous oxide emissions by 5%
below 1990 conditions by 2012
– US lobbied to have emissions
treated as commodities for
trading, banking, and borrowing.
– Developing countries were
exempt from emission limits
•
Earth Summit 2002- Johannesburg
–
–
It covered everything from measures to cut poverty,
improve sanitation, improve ecosystems, reduce
pollution, and improve energy supply for poor
people.
Boycotted by US Government
Intergovernmental Panel on
Climate Change (IPCC)
• http://www.ipcc.ch/ipccreports/ar4-syr.htm
• United Nations sponsored working group of
2400 scientists studied human caused sources
of climate change.
• Important conclusions:
– World climate has changed significantly over the past
century
– The balance of evidence suggests a discernible
human influence on global climate
– Climate models suggest that if current trends
continue, global mean surface air temp will increase
btwn 1ºC and 4.5ºC by 2100
What do the skeptics say?
(remember… these are skeptics)
• CO2 less potent than thought
• Methane levels declining
• Models should be predicting more
warming should be occurring but its not
• If temp increases, more clouds form, raise
earth’s albedo, atmosphere should cool
• Excess CO2 stimulates plant growth
• We are lucky to have CO2 otherwise we
would be on our way to new ice age.