Greenhouse gases

Definition

Greenhouse gases are atmospheric gases that trap heat from the Sun, contributing to the greenhouse effect and warming the Earth’s surface. Key greenhouse gases include carbon dioxide, methane, nitrous oxide, and water vapor.

5 Must Know Facts For Your Next Test

1. Greenhouse gases absorb infrared radiation and re-emit it, increasing the thermal energy in Earth's atmosphere.
2. The primary sources of increased greenhouse gases are human activities such as burning fossil fuels, deforestation, and industrial processes.
3. Carbon dioxide (CO2) is the most significant anthropogenic greenhouse gas due to its abundance and long atmospheric lifetime.
4. Methane (CH4) is over 20 times more effective at trapping heat in the atmosphere than CO2 on a per-molecule basis but has a shorter atmospheric lifetime.
5. Water vapor acts as a natural greenhouse gas but its concentration in the atmosphere is largely controlled by temperature.

Review Questions

• What role do greenhouse gases play in Earth's climate system?
• Name three major greenhouse gases and their primary sources.
• How does methane compare to carbon dioxide in terms of its effectiveness at trapping heat?

Related terms

Greenhouse Effect:

The process by which greenhouse gases trap heat in Earth's atmosphere, leading to an increase in global temperatures.

Carbon Cycle:

The biogeochemical cycle through which carbon is exchanged among the biosphere, geosphere, hydrosphere, and atmosphere.

Anthropogenic Climate Change: Climate change resulting from human activities such as emissions of greenhouse gases through burning fossil fuels.