13.2.2 Climate Change
William Patterson
Climate change, which is interchangeably referred to as global warming, is seen by many environmentalists as the most daunting challenge currently facing humankind. Scientists have concluded with very high confidence that contemporary climate change is primarily caused by human industrial and agricultural activities that are affecting the natural greenhouse effect. When heat first reaches the Earth’s surface from the sun, much of it is reflected back into space. Gases in the Earth’s atmosphere trap some of that heat, however, and prevent it all from escaping. This process is called the greenhouse effect, and it is what allows for a habitable temperature on Earth. Without it, the Earth would be too cold for human survival.
Human activity has altered this normal process by increasing the levels of greenhouse gases in the atmosphere, primarily carbon dioxide (CO²) and methane. CO² is produced by many industrial processes and the burning of fossil fuels for industry, transportation, household heating, and other uses. Fossil fuels are sources of energy, such as oil and coal, that contain a large amount of carbon, which is burned off and emitted into the atmosphere during use. Methane is also produced by industry, but it is emitted in the greatest quantities by farm animals, especially cattle and pigs, used for food.
Increased proportions of CO² and methane in the atmosphere have intensified the greenhouse gas effect, thereby trapping more and more heat at the Earth’s surface. This has resulted in an overall warming of the Earth, which in turn has intensified desertification, ocean acidification, and the power and frequency of weather events such as hurricanes and increased wildfires. It has also accelerated species extinctions as many plants and animals are finely tuned to life in particular climatic conditions and have been unable to survive as those conditions have changed.
- When the Sun’s radiation enters our atmosphere, it heats Earth.
- Earth gives off some of its heat radiation of its own. Some of this radiation passes through the atmosphere and into space.
- Some of Earth’s heat radiation is back, due to the greenhouse gasses in the atmosphere.
For many Greens, stopping and reversing climate change is their primary political goal. Global warming is seen as an existential threat to human beings and other life on Earth and is related to a number of other environmental problems.
