The term climate is used to describe weather conditions (including average and extreme conditions) over a long time period. The sun is the primary source of energy for the earth, but the distribution of this energy is determined by processes in the oceans, on land, and in the atmosphere involving factors such as ocean currents, clouds, ice, and living organisms. Because these factors vary throughout the globe, local climate varies by region.
- Climate change is a significant and persistent change in climate conditions, and occurs through a combination of natural and man-made processes.
- Greenhouse gasses such as water vapor, carbon dioxide, and methane absorb heat from the sun’s radiation and release this heat into the earth’s atmosphere. The presence of a small amount of greenhouse gasses in the earth’s atmosphere is important to maintaining an environment that supports life.
- Humans are increasing the amount of greenhouse gasses in the atmosphere by activities such as burning fossil fuels, which releases carbon dioxide. This addition of carbon dioxide into the atmosphere increases the amount of heat absorbed, drastically altering climate processes throughout the globe.
- The rate of temperature increase observed in recent decades far exceeds the rate at which would occur through natural processes that release carbon dioxide into the atmosphere, increasing scientist’s confidence in their conclusions that humans are altering the earth’s climate.
- All species are adapted to survive in specific ranges of temperature, pH, humidity, sunlight, and precipitation. As the climate changes, animals must move or adapt to new conditions, or they will die (NOAA Climate Literacy Principles).