Hot Days, Hot Nights
Paragraph A Here is what global warming could do in a few years: in Dallas, a doubled level of carbon dioxide would increase the number of days a year with temperatures above 100 degrees from nineteen to seventy-eight. On sixty-eight days, as opposed to the current four, the temperature wouldn't fall below 80 degrees at night. One hundred and sixty-two days a year, the temperature would top 90 degrees.
Paragraph B Although most scientists agree that increasing levels of carbon dioxide and other greenhouse gases will inevitably lead to global warming, no one is certain how fast and how much temperatures will rise and what the effects will be in any geographical areas. This gives policymakers an excuse for delaying action. Some experts predict that within two centuries glaciers in the North and South Poles will melt, ocean levels will rise, and much of what is now the coast of the United States will be under water. They also predict great droughts and hurricanes, as a result of climate changes.
Paragraph C Other scientists think the changes will be much more gradual, even beneficial. After all, Canada would not complain if the productive corn-growing lands - now located in the U.S. Midwest - were shifted north across the border.
Paragraph D While many nations could end up with milder climates, the change - perhaps 100 times faster than at any time in human history - could be so drastic that many of the benefits would be lost. There could be crowds of environmental refugees, as well, making the tragedy of the Dust Bowl era seem mild in comparison.
Paragraph E What can we do? Humanity's contribution to the greenhouse effect comes from so many basic activities that we can't hope to eliminate it completely. Some steps have already been taken. Since the 1970s, the use of CFCs as aerosol-can propellants has been banned in the United States.
Paragraph F Another strategy is to burn as much methane as possible. This adds CO2 to the air, but since methane traps twenty times as much heat as CO2, the net result is worthwhile. The gas in many garbage landfills is already being used in a number of places around the United States. It is being used to heat thousands of homes.