1. Global Climate Change:
Impact and Remediation

2. CQ#1: Based on your current knowledge, which statement is closest to your thoughts about the consequences for humans of global climate change?
The effects of climate change, if any, will be small compared to natural changes that have occurred before.
The effects of climate change will be minor except in poor, less developed countries.
Climate change will significantly affect many countries.
The effects of climate change will be catastrophic around the world. 2

3. Why is there so much concern about
climate change?
Predicted consequences of global climate change include:
Melting of continental and polar glaciers and sea ice.
A rise in sea level and loss of coastal communities.
Damage to ecosystems and reduced survival of threatened species.
Reductions in our food supply due to changes in agricultural conditions.
Increased threats to human health from new diseases and changing disease distributions.

4. 1. Glaciers are melting
According to the National Snow & Ice Data Center:
“Because glaciers are sensitive to temperature fluctuations, they provide clues about the effects of global warming. With few exceptions, glaciers around the world have retreated at unprecedented rates over the last century. Some ice caps, glaciers, and even an ice shelf have disappeared altogether. Many more are retreating so rapidly that they may vanish within decades.”

5. Glacial retreat can be judged from photographs taken from the same location decades apart.
Top photo: Collis, Septima M Muir Glacier: From the Glacier photograph collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media.
Bottom photo: Molnia, Bruce F Muir Glacier: From the Glacier photograph collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media.
Muir Glacier, Alaska, in 1890 (top) and 2005 (bottom).

6. Muir Glacier, Alaska, in 1880 (left) and 2005 (right).
Top left photo: Hazard, G.D Muir Glacier: From the Glacier photograph collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media.
Top right photo: Molnia, Bruce F Muir Glacier: From the Glacier photograph collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media.
Bottom left photo: Field, William O Muir Glacier: From the Glacier photograph collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media.
Bottom right photo: Molnia, Bruce F Muir Glacier: From the Glacier photograph collection. Boulder, Colorado USA: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media.

7. 1. Glaciers are melting
Melting glaciers, which supply drinking and irrigation water for hundreds of millions of people around the world, will be lost.
In addition, melting glaciers lead to rising sea levels and regional precipitation decreases.
Greenland:

9. 2. Sea level is rising
Because most glaciers are melting, sea level is rising.
In addition, the oceans’ surfaces are warming because of climate change, and this expands the water and adds to sea level rise. 9

10. 2. Sea level is rising
From , the estimated rate of sea level rise from both causes has been about 2.4 centimeters/decade.
Oceans are predicted to rise about 12 centimeters in the next 50 years.
Coastal erosion rates are about 100 times the rate of sea level rise, which means that every centimeter of sea level rise results in 1 meter of beach erosion.
Sea level rise estimates from C.M. Domingues et al., 2008, Improved estimates of upper-ocean warming and multi-decadal sea-level rise: Nature 453,
Leatherman et al., 2003, Sea Level and Coastal Erosion Require Large-scale Monitoring: EOS Trans. AGU 84 (2), 13. 10

11. Coastal Flooding and Erosion
Coastal Flooding and Erosion
Miami Beach,
Florida.
Current sea level (top);
Estimate at m (bottom)
Photos for Miami Beach from: Nation Under Siege: Sea Level Rise at Our Doorstep, 2007, Edward Mazria & Kristina Kershner, The 2030 Research Center. 11

12. Are larger changes possible?
Ice caps in Greenland and Antarctica together hold 70% of the world's fresh water— enough to potentially raise the sea level approximately 225 feet. But changes this large are thought to be extremely unlikely in the next century.
North and South Pole views.

13. Minimum extent of sea-ice for each year. Data from the National Snow and Ice Data Center (nsidc.org).

14. The implications of melting sea ice
Sea ice tends to reflect sun’s energy; sea water tends to absorb sun’s energy.
When more sea ice melts in summer, there is more open water to absorb energy and heat up.
The following winter it takes longer for sea ice to form due to warmer water and thinner ice.
Then, more melting takes place the next summer, which warms the water even more… and so on…
The “…and so on” is an indicator of a positive feedback process. Now that melting has started, it might accelerate because of the positive feedback. 14

15. Another positive feedback loop: Melting permafrost
Warming climate is melting the permafrost in Canada, Alaska, and Scandinavia.
This increases wetlands.
The wetlands release methane and carbon dioxide.
which are greenhouse gases … more positive feedback effects!

16. 3. Animals and ecosystems depend on climate
Polar bears and their prey need sea ice
Reef organisms depend on specific temperatures
Climate change adds to stress that may already exist from human use and pollution: Will these animals be able to adapt?

17. 4. Agricultural systems depend on climate
Climate change will affect production of food, fiber, and wood products.
Will the benefits of change exceed the losses?
Will agriculture be able to adapt to change?

18. Projected Changes in Agriculture in 2080 due to Climate Change
Wealthier nations may be better able to adapt.
Will they be able to feed the world?

19.
Morbidity (illness), mortality (death), and displacement (migration of population) could increase. For example, if malaria-carrying mosquitoes could move north, illness and death from malaria could move north as well, and people might respond by moving to even higher latitudes.

20. Health effects will not be the same everywhere
Which parts of the world have not been affected much by climate change so far? How and why might this change?

21. How do we cause climate change?
The most significant cause of climate change is emission of greenhouse gases (GHG), such as CO2, into the atmosphere from human activities.
In the U.S., most emissions result from using energy. Net emissions are large even though some land uses actually remove GHG from the air.
Data from “Inventory of U.S. Greenhouse Gas Emissions and Sinks: ”, US EPA, 2009 (EPA 430-R ), Table ES-4.

22. Responding to climate change
Mitigation
Reduce greenhouse gas (GHG) emissions. Drastic reductions could stabilize GHG in the atmosphere, but GHG remain in the atmosphere a long time so levels would not drop right away.
Sequestration. Land use and forestry practices that store CO2 in soil and plants can lower GHG levels in the atmosphere.
Photos copyright Tim Lutz

23. Responding to climate change
Mitigation
Geologic sequestration: Remove greenhouse gas emissions from the air and store it in the earth or oceans. But the technology to do this does not exist and might take decades to develop.
Adaptation
Climate change is occurring now and further change is inevitable. Adaptation means altering our economy and our lives to cope with those changes.
Rigs that pump oil out of Earth today might be able to put CO2 back in the future.
Photo: Offshore Platform Holly, South Ellwood Field, CA. U.S. Dept. of Energy (

24. Residential and commercial All of the above
CQ#9: In the graph below, direct emissions result from using fossil- based fuels such as gasoline and fuel oil while electricity-related emissions result from using fossil fuels, such as coal, to generate electricity. Thus, the generation of electricity represents the greatest proportion of GHGs in the ____ sector(s). (Choose the best answer)
Residential
Commercial
Industrial
Residential and commercial
All of the above
Data from “Inventory of U.S. Greenhouse Gas Emissions and Sinks: ”, US EPA, 2009 (EPA 430-R ), Table 2-14.

25. Practices and technologies
We can reduce emissions by:
Conservation: Use less energy (e.g., turn off lights, machines and engines when they’re not in use).
Conversion: Change to low-emission energy sources (e.g., renewable fuels emit fewer GHG than fossil fuels).
Efficiency: Use technologies that get the most from an energy source (e.g., Energy Star appliances).
Waste reduction: Eliminate materials that require energy to landfill (e.g., compost organics instead of creating trash).
Sequestration: take GHG out of the air (e.g., maintain and increase crops and land uses that hold carbon in soils).

26. What can you do?
The most important step is to find out how much GHG your lifestyle creates. Use one or more of the following online calculators to find out. Then use the GHG-reducing tips on these sites to reduce your GHG production.
The US EPA household emission calculator (
The Nature Conservancy carbon footprint calculator (
Carbonfootprint.com (