For many years it was seemingly impossible to say in which direction the climate was going. It wasn't until 1975 that highly sophisticated computer models predicted the temperature would rise by about 5 degrees Fahrenheit or 2.8 degrees Celsius, as many other professionals also believed. According to Tim Flannery, a well-known author, doubling the amount of carbon dioxide in the atmosphere would lead to a drastic increase in global temperatures. “Air pollution is causing a sizable share of global warming” (Walker, Sally M. and Tim F. Flannery. We Are the Weather Makers: The History of Climate Change). Carbon dioxide can be produced by respiration or by the decomposition of organic matter. It is vitally important for the Earth: it helps regulate the temperature of our planet's air and water. All plants use carbon dioxide during a process called photosynthesis: a process by which green plants and some other organisms use sunlight to synthesize food from carbon dioxide and water. Plants are vital to our planet because they produce oxygen, which we need to survive. Although carbon dioxide is also of great importance for our planet, it is definitely not a good thing that CO2 (carbon dioxide) levels are very high. When carbon dioxide levels are too high, it can cause what is known as greenhouse gas