Thousands of studies conducted by researchers around the world have documented increases in temperature at Earth’s surface, as well as in the atmosphere and oceans. Many other aspects of global climate are changing as well. High temperature extremes and
These trends are all consistent with a warming world and are expected to continue.
Many lines of evidence demonstrate that human activities, especially emissions of heat-trapping
Greenhouse gas emissions from human activities will continue to affect Earth’s climate for decades and even centuries. Humans are adding carbon dioxide to the atmosphere at a rate far greater than it is removed by natural processes, creating a long-lived reservoir of the gas in the atmosphere and oceans that is driving the climate to a warmer and warmer state.
Beyond the next few decades, how much the climate changes will depend primarily on the amount of greenhouse gases emitted into the atmosphere; how much of those greenhouse gases are absorbed by the ocean, the biosphere, and other sinks; and how sensitive Earth’s climate is to those emissions.
To learn more about the science of climate change, explore:
- NCA4 Volume I, Climate Science Special Report
- NCA4 Volume II, Ch.2: Our Changing Climate
- USGCRP Indicators