Global warming, also referred to as climate change, is the observed century-scale rise in the average temperature of the Earth's climate system, and its related effects. Multiple lines of scientific evidence show that the climate system is warming. Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record, which extends back to the mid-19th century, and in pale climate proxy records covering thousands of years.

Global Warming

The Greenhouse Effect

The main driver of today's warming is the combustion of fossil fuels. These hydrocarbons heat up the planet via the greenhouse effect, which is caused by the interaction between Earth's atmosphere and incoming radiation from the sun. "The basic physics of the greenhouse effect were figured out more than a hundred years ago by a smart guy using only pencil and paper," Josef Werne, a professor of geology and environmental science at the University of Pittsburgh, told Live Science.That "smart guy" was Svante Arrhenius, a Swedish scientist and eventual Nobel Prize winner. Simply put, solar radiation hits Earth's surface and then bounces back toward the atmosphere as heat. Gases in the atmosphere trap this heat, preventing it from escaping into the void of space (good news for life on the planet). In a paper presented in 1895, Arrhenius figured out that greenhouse gases such as carbon dioxide could trap heat close to the Earth's surface — and that small changes in the amount of those gases could make a big difference in how much heat was trapped.

Effects of global warming

Global warming doesn't just mean warming — which is why "climate change" has become the trendier term among researchers and policy makers. While the globe is becoming hotter on average, this temperature increase can have paradoxical effects, such as more serious snowstorms. There are several big ways climate change can and will affect the globe: By melting ice, by drying out already-arid areas, by causing weather extremes and by disrupting the delicate balance of the oceans.

Hotter and drier

Global warming will change things between the poles, too. Many already-dry areas are expected to become even drier as the world warms. The Southwest and Central Plains of the United States, for example, are expected to experience decades-long "megadroughts" harsher than anything else in human memory."The future of drought in western North America is likely to be worse than anybody has experienced in the history of the United States," Benjamin Cook, a climate scientist at NASA's Goddard Institute for Space Studies in New York City who published research projecting these droughts in 2015, told Live Science. "These are droughts that are so far beyond our contemporary experience that they are almost impossible to even think about."The study predicted an 85 percent chance of droughts lasting at least 35 years in the region by 2100. The main driver, the researchers found, is the increasing evaporation of water from hotter and hotter soil. Much of the precipitation that does fall in these arid regions will be lost.Meanwhile, 2014 research finds that many areas will likely see less rainfall as the climate warms. Subtropical regions, including the Mediterranean, the Amazon, Central America and Indonesia will likely be hardest hit, that study found, while South Africa, Mexico, western Australia and California will also dry out.