The most common climate problems are global warming and climate change. Global warming is the unusual heating up of the Earth. It is caused mostly by the upsurge of greenhouse gases, such as carbon dioxide and methane, into the Earth’s atmosphere; this is the layer composed of gases and clouds. Climate change refers to the shift in the elements of the climate that can alter landscapes, influence the daily lives of communities, and cause changes in the growth of crops. Both climate problems are caused by many factors, although human activities have been largely blamed by much of the scientific community for years.
At the start of the 20th century, experts observed that the Earth’s atmosphere was experiencing a slight warming. This occurrence was initially appreciated by the scientific community, considering that it protected the earth against the glaciers of a new ice age. The rate of warming, however, became so alarming that scientists began to conduct research on how this occurrence might possibly be stopped or minimized.
Naturally, greenhouse gases trap some of the sun’s energy in the Earth’s atmosphere, a phenomenon called the greenhouse effect. Shortwave radiation from the sun can pass through these gases; however, long-wave radiation that is supposed to be transmitted back to outer space is being blocked by these gases, where it becomes trapped in the Earth’s atmosphere. When more greenhouse gases are introduced into the atmosphere, more radiation is trapped, resulting in climate problems such as global warming. Global warming, in turn, creates climate change.
Many years ago, the Earth experienced changes in climate that happened over a long period. For instance, the climate became cooler during the ice ages, but became warmer again after millions of years had passed. Since the 18th century, however, climate changes have occurred more rapidly; these changes have greatly affected the Earth and everything on it, thus prompting scientists to conduct extensive research. The causes of climate change in the distant past are considered purely natural, such as volcanic eruptions and meteoric impacts. Climate change in recent years, however, has been linked to human activity, such as the release of chemical compounds used in certain agricultural practices.
Fossils, soils, trees, and glacial deposits reveal evidence of climate trends. For instance, growth ring patterns of trees provide evidence of shifts in rainfall and temperature. A wide growth ring is formed during cold climate or when there is adequate rainfall; a narrow growth ring is formed during warm climate or when there is less rainfall. Today, direct evidence of climate problems and trends is recorded using modern instruments such as satellites.