What is Global Climate Change?
Global climate change is one of the worlds most serious and complex challenges. It is the destabilization of the earths climate system caused by an increase in the concentration of greenhouse gases (GHGs) in the atmosphere (see Box 3: Greenhouse Gases). These gases absorb infrared radiation as it is reflected from the earths surface, acting like a blanket, trapping heat, and keeping the earth warm. The earths atmosphere has always contained GHGs, which in fact keep our planet about 30 C (54 F) warmer than it would be otherwise. However, since the beginning of the Industrial Revolution, the levels of GHGs in the atmosphere have grown rapidly as a result of human activities, particularly the burning of fossil fuels like coal, oil, and natural gas as an energy source. The current concentrations of GHGs in the atmosphere are at levels unprecedented in at least the last 650,000 years (1) and as a result, the earths climate is warming. The most significant GHG is carbon dioxide (CO2), which
By adding carbon dioxide, methane and other greenhouse gases to Earth’s atmosphere, humans are enhancing its ability trap the warmth radiated by the sun. Scientists observe this greenhouse effect in countless ways, including the correlation between steadily rising carbon dioxide levels and dwindling Arctic ice cover. Together with computational climate models, these observations suggest that conditions on Earth are shifting to a warmer state. This global climate change could affect everything from sea level to the distribution of plants and animals.
