In the past, a one- to two-degree drop was all it took to plunge the Earth into the Little Ice Age. The amount of energy radiated by the Earth depends significantly on the chemical composition of the atmosphere, particularly the amount of heat-trapping greenhouse gases.ДЄ one-degree global change is significant because it takes a vast amount of heat to warm all the oceans, atmosphere, and land by that much.

But the global temperature mainly depends on how much energy the planet receives from the Sun and how much it radiates back into space-quantities that change very little. The temperatures we experience locally and in short periods can fluctuate significantly due to predictable cyclical events (night and day, summer and winter) and hard-to-predict wind and precipitation patterns. The global temperature record represents an average over the entire surface of the planet.

Two-thirds of the warming has occurred since 1975, at a rate of roughly 0.15-0.20вЊ per decade.Д«ut why should we care about one degree of warming? After all, temperatures fluctuate by many degrees every day where we live. Thermometer readings around the world have been rising since the Industrial Revolution, and the causes are a blend of human activity and some natural variability-with the preponderance of evidence saying humans are mostly responsible.ДЄccording to an ongoing temperature analysis conducted by scientists at NASAвЂ™s Goddard Institute for Space Studies (GISS), the average global temperature on Earth has increased by a little more than 1В° Celsius (2В° Fahrenheit) since 1880.

Rise of nations world map