HUMANITY AND THE WEATHER

HUMANITY'S IMPACT

Has the weather ever been responsible for killing a U.S. president?

When U.S. President William Henry Harrison (1773-1841) gave his inaugural address on March 4, 1841, the weather was miserable. Despite snow and bitter cold, President Harrison insisted on remaining outside and giving one of the longest inaugural addresses ever (1 hour and 45 minutes). At 68 years old, the former general and war hero was not in the most robust health, and many blamed the weather conditions as the cause of President Harrison's subsequent pneumonia. One month after becoming president, he died, thus earning him the distinction of the U.S. president serving the shortest term in office.

What are the consequences in the United States when there is an unusually cool summer?

Cooler than normal summers can have both benefits and drawbacks. Drawbacks include poorer crop harvests and, in states where summer tourism is important, reduced income for businesses and fewer tax dollars for local government. People tend to run their air conditioners less, as well, which is good for the environment but hard on utility companies trying to maintain a profit. Meanwhile, consumers save on utility expenses. As one might guess, incidents of heat stroke and dehydration are reduced and hospitals see fewer patients stricken by these problems.

Is Earth's atmosphere changing?

Earth's atmosphere is continually and gradually changing. Over cycles that usually last many thousands of years, the concentrations of different gases—including oxygen, carbon dioxide, and others—go up and down, as does the concentrations of tiny dust particulates such as carbon soot.

In the past hundred years or so, human population growth and industrial activity has caused a much sharper change in the concentrations of some gases and particulates on a much shorter timescale than at any time in the past 200,000 years. The most dramatic effect has been a huge increase in the amount of carbon dioxide in the atmosphere. This increase has created a substantial greenhouse effect, according to some scientists, which could be increasing the average temperature on Earth at a much faster rate than typical ecological and geological timescales.

What is weather modification?

Since the advent of agriculture, when food supplies waxed or waned depending on the weather, human civilizations have wanted to control the weather. Ancient civilizations typically did this by praying to gods or to one God to bring rain and prosperity. In the twentieth century, however, science finally seemed to offer hope that our understanding of chemistry and meteorology could be used to affect the weather. There was considerable hope that cloud seeding, discovered in 1946, could make droughts a thing of the past. The potential of this technique never met expectations, though it still can be used under the right conditions; seeding techniques are also employed to reduce the size of hail stones so they will cause less damage. The Weather Modification Association, which was established in 1950, is still active today and supports research in this area.

What is inadvertent weather modification?

This, of course, means accidentally changing the weather, usually for the worse. Humanity has been very good at that, especially as a result of activities that lead to deforestation and pollution. It is now common knowledge that chemicals from cars and industry are destroying the ozone, and particulates from emissions also have an effect on precipitation. Cutting down forests in favor of croplands, urban construction, golf courses, and so on causes more sunlight to be reflected back into the atmosphere but can also cause urban heat islands. Animal agriculture can increase methane gas in the atmosphere, and irrigation of plants alters water distribution. All of these activities and more have noticeably changed natural weather patterns and the climate without humans intending to do so.

Who first theorized that human activities were causing climate change?

The Swedish scientist Svante August Arrhenius (1859-1927), who was one of the founders of the discipline of physical chemistry, is sometimes credited as the first person to discuss in detail the effects of carbon dioxide (CO2) on Earth's climate. Arrhenius came upon his theory while studying past ice ages, and in 1896 published a paper in which he proposed that ice ages occur when CO2 levels go down. By his estimates, doubling CO2 amounts would increase average world temperatures by about 2.5°F (5°C) and halving the levels of this gas would have the opposite effect.

Recent modeling studies come quite close to Arrhenius's original estimate. Unlike today's environmentalists and climatologists, however, the Swedish scientist believed that global warming would be a good thing for two reasons: it would help prevent another ice age and it would aid in crop production to feed a hungry world.

Why are trees and other vegetation important to the weather and climate?

Cutting down trees, especially on the massive scale that is occurring today, has a definite effect on the weather in several ways: 1) trees and other plant life absorb carbon dioxide and other pollutants that cause global warming; 2) plants also absorb sunlight and areas covered by forest thus reflecting less sunlight back into the atmosphere; 3) trees near homes and commercial buildings help reduce electricity use because they keep buildings cooler in the summer and serve as a barrier against cold winds in the winter.

What is the current extent of deforestation?

Worldwide, we are losing enough forestland annually to cover an area the size of the state of Panama. To put that figure into numbers, that is a net loss of 7.3 million hectares (18 million acres) every year. Actually, about 13 million hectares (32 million acres) are being chopped down yearly, but there are restoration projects going on that help replant forests. This rate of loss (which is an average taken from the years 2000 through 2005) is somewhat better than the 8.9 million hectare (22 million acre) loss that was experienced during the previous decade. Although replanting is great, new forest growth does not make for as healthy a habitat for wildlife as old forest growth.

Farmers in Brazil use fires to clear away forest, which can easily be seen in this satellite photo. (NASA)

Farmers in Brazil use fires to clear away forest, which can easily be seen in this satellite photo. (NASA)

 
< Prev   CONTENTS   Next >