Change

Scientists at NASA have determined that ozone and climate affect each other. According to Bill Stockwell of NASA's Desert Research Institute, temperature, humidity, winds, and the presence of other chemicals in the atmosphere influence ozone formation and the presence of ozone, in turn, affects those atmospheric constituents. When humans first began to harm the ozone layer in the early 1970s through the use of CFCs and halons (halons are a compound of one or two carbon atoms combined with bromine and one or more other halogens. Halons are gases used as fire-extinguishing agents. They are between three and 10 times more destructive to the ozone layer than CFCs.), causing a hole to form in the layer, research and international cooperation helped turn the harmful trend around. Scientists then predicted that under strict control it would be possible to see ozone levels completely recovered by the year 2050.

Recently, some startling new findings by NASA were introduced. They believe that even before the ozone's projected 2050 recovery, that ozone's effects on climate may become the main reason for ozone loss in the stratosphere. During the winter months, a vortex of winds develops around the polar regions, isolating the polar stratosphere. When temperatures drop below -109°F (-78°C), thin clouds of ice, nitric acid,

surface's albedo. Ice caps and light color rocks, for example, have a high albedo, whereas dark soil and deep lakes have a low albedo. The texture of the surface and the angle of the Sun also determine how much energy is reflected or absorbed. A smooth texture or low Sun angle will reflect more energy.

In the last 35 years NASA scientists have determined that the amount of radiation the Sun emits during times of quiet sunspot activity has increased by .05 percent per decade. They believe this is important because if it increased steadily for many decades, it could cause significant climate change. Increased solar radiation leads to increased warming, which could add significantly to global warming. NASA's sci-

and sulphuric acid mixtures form. Chemical reactions on the surfaces of ice crystals in the clouds release active forms of chlorofluorocarbons (CFCs). Ozone depletion occurs, causing an ozone hole to appear. In the spring when temperatures begin to rise, the ice evaporates and the ozone layer begins to recover once again. Because of this, scientists are now warning that the ozone layer may not be fully recovered until 2060 or 2070.

Ozone influences climate through temperature. The more ozone that is in a given region of air, the more heat it retains. Ozone generates heat in the stratosphere in two ways: (1) it absorbs the Sun's UV radiation (which is especially helpful to humans for protection against harmful sunrays), and (2) it absorbs the longer infrared radiation that is reflected up from the lower atmosphere (the troposphere).

Decreased ozone in the stratosphere lowers temperatures. It has been determined that the mid to upper stratosphere has cooled by 2 to 11°F (1-6°C). This cooling period corresponds to when greenhouse gas amounts in the lower atmosphere (troposphere) have risen. Scientists at NASA think these two phenomena may be connected. The exact link between climate, ozone, and temperature is one that climatologists want to build more powerful models for.

Source: NASA, Goddard Institute for Space Studies entists said that if this trend continued for a century or more it could significantly affect the outcome of global warming. Total solar irradi-ance (TSI) is the radiant energy received by the Earth from the Sun, over all wavelengths, outside the atmosphere. TSI interaction with the Earth's atmosphere, oceans, and landmasses is the biggest factor determining our climate. Even relatively small changes in this could have significant climatic effects.

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