About global warming

When people say global warming, they're often talking about the rise in average temperature of the Earth's climate system since the late 19th century. Temperatures over the land and ocean has increased roughly 0.8° Celsius in that  particular span. Some places have warmed more, some less. But that's the worldwide average:

The consensus among climate scientists is that this recent temperature increase has been driven primarily by the extra greenhouse gases that humans have put into the atmosphere since the Industrial Revolution. Greenhouse gases, such as carbon dioxide, trap heat at the Earth's surface, preventing that heat from escaping back out into space too quickly. So when we burn materials such as coal or oil for energy or cut down forests, carbon dioxide is released into to the atmosphere which warms the planet up.Global warming also refers to what scientists think will happen in the future if humans still continue to add greenhouse gases to the atmosphere.

A 2013 report from the Intergovernmental Panel on Climate Change projects that temperatures could rise at least 2°C by the end of the century under many plausible scenarios — and possibly 4°C or more.A 4-degree rise is considered to be an enormous change to the environment. Many experts and politicians consider even 2°C  of global warming to be extremely dangerous, increasing the risk of deadly heat waves, droughts, flooding, and extinctions. Rising temperatures will as well as drive up global sea levels as the world's glaciers and ice sheets melt. Further global warming could effect everything, from our ability to grow food to the spread of disease.