Transcript PowerPoint Presentation - ESC 110: Global Climate Change

ESC 110: Global Climate Change:
Impact on Biological Systems
Changes in
glacial ice massIndication of
Climate change
Bob Edmonds
Forest Resources
Reading p. 195-209
Lecture Topics
1. Is global warming really happening?
2. Greenhouse gases and increases in CO2
3. Climate in the past, present and future
4. What effect will climate change have?
5. What can we do about it?
1. Is global warming really happening?
GCC: Fact or Fiction
From an environmental textbook:
One of “the two most immediate
global environmental threats
humans face is climate change
caused by greenhouse gases. This
is caused by the introduction of
large quantities of humanproduced gases into the
atmosphere.” Are these
statements true? Does everyone
agree with them?
GCC: Givens
• Climate will change (because it has changed).
• Carbon dioxide levels are increasing in the
atmosphere
• The greenhouse effect is real (and important).
GCC: Questions
• How will the climate change and how much will the
climate change?
• Is the change natural or due to human activities?
• If there is climate change, will it affect me?
Human-Caused Global Climate
Change
• IPCC (2001) released report stating “recent
changes in the world’s climate have had
discernable impacts on physical and
biological systems.”
– Concluded human activities must be at least
partially responsible.
2. Greenhouse gases and increases in CO2
GCC: Greenhouse effect
• The greenhouse effect is caused by trace gases in the
atmosphere (water vapor, carbon dioxide, methane,
others)
2
Greenhouse Gases
• Carbon Dioxide - Fossil-fuel burning.
• Atmospheric levels increasing steadily.
• Methane - Ruminants, Coal-mines
• Absorbs more infrared than CO2.
• Chlorofluorocarbons (CFC’s) - Refrigerants
• Declined in recent years
• Nitrous Oxide - Burning organic material
• Sulfur Hexafluoride - Electrical insulation
Table 9.3
GCC: Changes in a greenhouse gas
Increasing
Pattern
Biological activity
Human activity
3. Climate in the past, present and future
GCC: Present Temperature Change to
Historical
Fig. 9.9c
Fig. 9.9d
West Olym pic Coastal Division, Washington Tem perature(C)
Climate Division (01), 12 month period ending in December
12 month
period
11
Tem perature (C)
10 year
running mean
10
average
+sigma
9
-sigma
8
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
Ending Year of Period
Cascade Mountains West Division, Washington Tem perature (C)
Climate Division (05), 12 month period ending in December
12 month period
Temperature (C)
10
9
10 year running
mean
8
average
7
6
-sigma
5
+sigma
4
1890
1900
1910
1920
1930
1940
1950
1960
Ending Year of Period
1970
1980
1990
2000
Tem perature (C)
CO Drainage Basin (S) Division, Colorado Tem perature (C)
Climate Division (02), 12 month period ending in December
9
12 month period
8
7
10 year running
mean
average
6
-sigma
5
4
1890
+sigma
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
Ending Year of Period
South Central Division, Florida Temperature (C)
Climate Division (04), 12 month period ending in December
12 month
period
Tem perature (C)
24
10 year
running mean
23
average
22
21
1890
-sigma
+sigma
1900
1910
1920
1930
1940
1950
1960
Ending Year of Period
1970
1980
1990
2000
LARGE SCALE CLIMATE PERTURBATIONSEL NINO AND LA NINA
El Nino Southern Oscillation
El Nino Southern Oscillation
• Large pool of warm surface water in Pacific
Ocean moves back and forth between
Indonesia and South America.
– Most years, the pool is held in western Pacific
by steady equatorial trade winds.
• Every three-five years the Indonesian low collapses
and the mass of warm surface water surges back
east.
El Nino Southern Oscillation
– During an El Nino year, the northern jet stream
pulls moist air from the Pacific over the U.S.
• Intense storms and heavy rains.
– During intervening La Nina years, hot, dry weather is
often present.
GCC: Climate Change: Predictions
MODEL
Know CO2 will continue to increase
Greenhouse effect should increase
Therefore temperature should increase
Four responses:
• A disaster
• The best news ever
• Do not know enough
• Natural cycles dominate
The Pacific Northwest is likely to have
hotter, drier summers and warmer,
wetter winters.
4. What effect will climate change have?
EFFECTS OF CLIMATE CHANGE ON:
Agriculture - increase agricultural yields in Canada; could reduce in
U.S.
Forests - change species distributions, more forest fires
Water – stream flows could be less in some areas; big competition for
water
Fish - could increase stream temperatures; reduce salmon
Coral reefs - killing of reefs (bleaching)
Wildlife – some species could go extinct; reduce biodiversity
People - sea level rise will flood coastal cities, water supplies
could be reduced, more fires, hotter in summer(more need for
air conditioning and energy), reduced snow for skiing.
Could result in rapid global cooling (breaking the conveyor belt)
Modern Glacial Retreat in Switzerland
NOW
THEN
Consequences of Changes in Global
Snow/Ice Coverage
• Northern latitudes have warmed more than
the global average.
• Spring is coming sooner to northern latitudes.
• Examined 10 plus year record of almost 300
different species: Changes in phenology
(when leaves appear, migration, nesting,
hibernation) and distribution and abundance
• Seasonal water shortages
• Loss of glaciers (e.g., Glacier Nat’l Park)
Consequence of this warming?
Feedback: Less snow, means warmer
winters, earlier springs.
Further:
Changes in species distribution
Changes in biological communities
GCC: Implications on Plants
Species responses
Disturbance regimes
Rapid melting of polar ice in the North Atlantic
could break the heat conveyer belt in the oceans and
cause rapid cooling. Scarey!!
5. What can we do about it?
GCC: Let’s assume we need to do
something, then what?
• Conservation – reduce fossil fuel energy use
• Alternative energy sources
• Regulate carbon dioxide emissions ( 1997
Kyoto Protocol – U.S. has not signed)
• Carbon tax
• Use plants (trees) to take up or sequester the
carbon.
GCC: Solutions with plants
• Balance the net gain of global carbon by the
atmosphere through planting young forests
requires over 109 hectares of young forest,
~14 times the size of Washington State.
• Balancing the CO2 input from the US alone
would require an area ~3 times Washington
State ( ~1.2 times the size of California)
• If you burn it then it goes back to the
atmosphere. Could bury trees in the ocean.
GUILT
Global Climate
Change: Summary.
Climate has changed in the past and will in
the future
Humans have contributed
Climate change has consequences
We are involved in a massive experiment
You are the observers of this experiment.
You will need to address whether & when
something should be done & how.