Regional Problems Ahead
The list of potential problems associated with global warming is long: changing precipitation patterns with lack of water in some places and floods in others; changes in the frequency of storms (more heat and water vapor in the air means more energy is available for making hurricanes); greater weather extremes (again, due to more energy being available in climate system); fundamental changes to the circulation of the ocean (resulting in a loss of heat to Scandinavia); fundamental changes to “productivity,” that is, the population of marine microorganisms called plankton that form the base of the ocean’s food chain (due to changes in the wind field and the strength of upwelling of cold water along the coast); changes in sea level (resulting in flooding for low-lying coastal plains and many islands in the central Pacific); increased soil erosion in places; changes in vegetation patterns; and permafrost melting in the tundra.
Fears that such problems are coming down the road are justified in many cases: sea level has indeed been rising by roughly an inch per decade; great floods associated with El Niño conditions have done enormous damage in the 1980’s and 1990’s; hurricane production in the Caribbean has been unusually vigorous lately; and permafrost is melting in Alaska, resulting in destroyed roads and houses.
Potential Sea-Level Changes
If Earth's climate continues to warm, then the volume of present-day ice sheets in the Arctic and Antarctic will decrease. Melting of the current Greenland ice sheet would result in a sea-level rise of about 6.5 meters; melting of the West Antarctic ice sheet would result in a sea-level rise of about 8 meters.
Red shows areas along the Gulf Coast and East Coast of the United States that would be flooded by a 10-meter rise in sea level. Population figures for 1996 (from the U.S. Bureau of the Census, unpublished data, 1998) indicate that a 10-meter rise in sea level would affect approximately 25 percent of the Nation's population. (Adapted from: USGS Potential Sea Level Changes web page at U.S. Geological Services
Reduction of the West Antarctic and Greenland ice sheets similar to reductions in the recent geologic past would cause sea level to rise 10 or more meters. A sea-level rise of 10 meters would flood about 25 percent of the U.S. population, with the major impact being mostly on the people living in the Gulf and East Coast States.
How important one thinks each of the problems that may come climate change are depends on where one lives and on one’s level of income. People who live far inland may not care about the rise of sea level. Those who live on coral islands are not concerned about the melting permafrost in Alaska. Those who are well off may feel they could simply move to places where they are more comfortable. Individuals who live in high latitudes where winter is severe may actually welcome global warming since it may bring an earlier summer with a longer crop growing season. However, each of these individuals will be affected by global climate change in one way or another.
Confronting Climate Change in California
What is the likely climate future for California? This issue has been addressed by the Union of Concerned Scientists (Log on to their interactive website Union of Concerned Scientists for lesson plan ideas). It is highly probable that temperatures will increase by 5-6° F in winter and 1-2° F in summer. Also, more extreme weather events are expected including bigger and more frequent storms with more severe summer droughts. Sea level is expected to rise by 8 –12 inches by 2100 (at a rate 2-3 times that experienced in San Francisco over the last 150 years). Finally, El Niño events are expected to increase in intensity and/or frequency as the climate changes (We will learn more on the El Niño phenomenon in Lesson 6.).
These warming temperatures and dramatic changes in precipitation patterns are likely to have an impact on California’s natural ecosystems. For example, since 1976-77 ocean waters warmed off the coast of Southern California and productivity has greatly decreased. Also, there has been a distinct change in fish species composition.
Another list of specific problems ascribed to global warming can be found at another link offered by the Union of Concerned Scientists (Go to Climate Hot Map). Remember, although there is no absolute proof that global warming is the cause in the calamities listed above, it is quite possible that they are.
The changes in Southern California’s marine ecosystem since the mid-1970’s. Increased warming of the waters off Los Angeles have resulted in a 50% decline of cold-water, northern fish species (like the greenspotted rockfish), while warm-water southern fish species (like the Garibaldi) have increased by 50%. (Redrawn with permission from: Confronting Climate Change in California
, Union of Concerned Scientists, 1999. The complete report can be accessed at www.ucsusa.org