Transcript greenhouse gases - UW Program on Climate Change

Climate Change and Its Impacts
University of Washington
Program on Climate Change
Who we are…
Graduate Students, University of Washington
Program on Climate Change
• Shelley Kunasek
• Justin Minder
What have you heard?
Climate
Climate Change
Our Questions Today
•
•
•
•
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What are Greenhouse Gases?
How do they cause warming?
How are humans affecting temperatures?
How do we know?
Can we predict how the Earth’s climate might
change?
• What might happen here in Washington?
Greenhouse Gases
Greenhouse
gases
GHG
GHG
GHG
• Sunlight heats the
earth
• Some of sun’s
energy is
reradiated from
surface.
• GHGs absorb this
energy
• GHGs reradiate
some escaping
energy back
towards surface,
making the
temperature warmer
Source: Murray ca. 2005
Most Important Greenhouse Gases
GHGs:
• Water: H2O
• Carbon Dioxide: CO2
• Methane: CH4
Source Examples:
Oceans, Rivers, Plants, Soil
Combustion, Respiration
Wetlands, Oceans,
Combustion, Animals
http://www.for.gov.bc.ca
Source: U.S. EPA 2005
Human sources of Greenhouse Gases
Halocarbons
2%
Other
CH4
8%
N2O
5%
CO2
4%
CO2 from
fossil fuels
81%
• ~50% of CO2 emissions
to atmosphere are
currently from humans
• Fossil Fuel burning
represents 81% of
human sources of GHGs
• Fossil Fuels include coal,
oil, and natural gas.
Source: U.S. EPA 2005
Past and Present:
Greenhouse Gases and Climate Change
Observations of CO2 1958 to present
• CO2 concentrations have increased since 1958
• Estimated increase of about 30% since 1850
(280 ppm to 370 ppm)
Source: Murray ca. 2005
Temperature ( C )
Temperature ( F )
Instrumental Temperature Record
Source: NOAA
More Evidence: Ice Cores
• Ice layers preserve information about each year
Sources: NOAA, GISP2 websites
Ice Core Evidence
CO2 and temperature, 420,000 BP to present
4
2
340
0
300
-2
-4
260
-6
220
-8
180
Temperature differential, ºC
CO2 concentration, ppmv
380
-10
0
50,000
100,000
150,000
200,000
250,000
300,000
350,000
400,000
Years BP
Temperature differential
CO2 concentration
Source: various, (1) Vostok assembled by Davies 2000, (2) GISP2
Future Climate Changes
Predicting Future Climate Change
Animation
Schematic of a GCM
Future global climate change
• Model predictions of global average temperature
increases by 2100 range from +2 to +4.5°C (4-8 ° F)
Source: IPCC 2001
Future local climate change
Average Northwest warming, 2000-2100
Source: Mote, Salathé and Peacock 2005
Impacts of Global Warming
Impacts of Climate Change
• Sea level rise
• Ecosystem disruption
• Changes in extreme events
• Hurricanes (intensity)
• Droughts
• Societal
• Water resources
(droughts, snowpack,…)
• Businesses (ski
industry)
• Loss of winter snowpack
• Health (spread of
disease, heat,…)
• Loss of Sea ice
• Forestry
• Changing climate zones
• Agriculture
• Coral death
Sea Level Rise
1-5 meters in Bangladesh
7-8 meters in Florida
Loss of Sea Ice
Source: Arctic Climate Impact Assessment (ACIA) (2004)
Retreat of the South
Cascades glacier
1928
• Also: reduction of winter
snowpack and reduces
freshwater supply
2000
Source: USGS ca. 2005
Effects on salmonid life-cycle
winter
flooding
possible
effects
still
unknown
low summer
streamflow;
higher temp.
changing estuary
conditions (prey,
predators,
competitors)
Source: Mote ca. 2005
Vegetation carbon in 2070-2100
Modeled
Change in
Vegetation
Current
vegetation as
seen from
satellite
Source: Nielson ca. 2005
NASA Landsat Geocover 2000
Our Future Depends on Our Choices
Choices are difficult because they require
value judgments and long-term planning
Reducing Greenhouse Gases Requires:
Government actions:
• International agreements are
modest and do not have
unanimous support
• US does not support
• Support for alternative
energy
Personal actions:
• Reduce energy use:
• at home
• drive less, drive
efficient
• Get political
• support businesses
that are energy
conscious
• vote
Our Future Depends on Our Choices
Choices are difficult because they require
value judgments and long-term planning
Also Important:
Planning for how to deal with future climate changes
•Preparing for water shortages
•Preparing for sea level change
•Preparing for ecosystem impacts
Summary
• Human activities are increasing greenhouse
gases (like CO2) all over the world.
• As a result, the average temperature of the
world is increasing.
• Future warming of at least 1C by 2050
• Future climate depends on our choices
The End.
University of Washington
Program on Climate Change
Extras:
Natural Climate Influence
Human Climate Influence
All Climate Influences
Temperature change, 2071-2100 minus 1961-1990
Extras:
Extras: Measured Arctic Summer Sea Ice Extent
Sea level rise
IPCC (www.ipcc.ch)
U.S.
186.1
Total
CO2
emission
s since
1950 in
billions
of tons
European
Union
127.8
Russia
68.4
Ukraine
21.7
China
Poland
14.4
Canada
Kazakhstan
14.9
10.1
57.6
Japan
31.2
India
15.5
Mexico
7.8
Kuwait
Trinidad and
Tobago
Australia
South Africa
8.5
United
Arab
Emirate
s
7.6
Trends in April 1 snow water equivalent, 1940-1992
As the West warms,
winter flows rise
and summer flows
drop
Figure by Iris Stewart,
Scripps Inst. of Oceanog.
(UC San Diego)
Greenhouse gases and Earth’s energy balance
* H2O, O3, CO2, CH4, N2O, halocarbons
Source: Murray ca. 2005