1. Environmental Science Witt
Global Warming
Environmental Science
Witt

2. How Certain is Global Warming?

3. The Greenhouse Effect
The Earth is similar to a greenhouse. The Earth’s atmosphere acts like the glass in a greenhouse.
Sunlight heats the Earth.
As this heat radiates up from Earth’s surface, some of it escapes into space.
The rest of the heat is absorbed by gases and warms the air.

4. The Greenhouse Effect

5. The Greenhouse Effect
Not every gas in our atmosphere absorbs heat in this way.
A greenhouse gas is a gas composed of molecules that absorb and radiate infrared radiation from the sun.
The major greenhouse gases are water vapor, carbon dioxide, CFCs, methane, and nitrous oxide.
water vapor and CO2 account for most of the absorption

6. The Consequences of a Warmer Earth
Sea levels around the world to rise.
Coastal wetlands could be flooded.
People losing their homes and income.
More hurricanes and typhoons

7. The Consequences of a Warmer Earth
A change in ocean current patterns, shutting off the Gulf Stream.
Severe flooding in some regions
Droughts in other regions

8. Human Health and agriculture
Greater numbers of heat related deaths could occur.
Increased respiratory illnesses, especially in urban areas
More mosquitoes, which carry diseases such as malaria and encephalitis

9. Human Health and agriculture
Drought
Higher temperatures, decreased crop yields.
Demand for irrigation could increase depleting groundwater supply

10. Effects on Plants and Animals
Alter the range of plant species
Change the composition of plant communities.
Trees to colonize northward into cooler areas.
Forests could shrink and lose diversity.

11. Effects on Plants and Animals
Northern birds may not migrate as far south during the winter.
Reduction of zooplankton, tiny shrimp-like animals, that many marine animals depend on for food.
Kill algae that nourish corals, thus destroying coral reefs.

12. Reducing the Risk
(1997) Kyoto Protocol ratification required developed countries to decrease emissions of carbon dioxide and other greenhouse gases by an average of 5 percent below their 1990 levels by 2012
(2001) U.S. did not ratify the Kyoto Protocol
Canada withdrew: 2012
(2016) Paris Agreement to start in 2020: limit global temperature increase, less greenhouse gas emissions

13. Reducing the Risk Reforestation projects to reduce carbon dioxide
Difficult by the economic, political, and social factors faced by different countries
Conflict between developed and developing countries

14. Reducing the Risk
Developing countries are projected to make up half of all CO2 emissions by 2035.