Climate change feedback

Climate change feedbacks are effects of global warming that amplify or diminish the effect of forces that initially cause the warming. Positive feedbacks enhance global warming while negative feedbacks weaken it.[4]^: 2233 Feedbacks are important in the understanding of climate change because they play an important part in determining the sensitivity of the climate to warming forces. Climate forcings and feedbacks together determine how much and how fast the climate changes. Large positive feedbacks can lead to tipping points—abrupt or irreversible changes in the climate system—depending upon the rate and magnitude of the climate change.[5][6][7][8][9]

The main positive feedback in global warming is the tendency of warming to increase the amount of water vapor in the atmosphere, which in turn leads to further warming.[10] Positive climate feedbacks include the carbon cycle positive feedbacks which include arctic methane release from thawing permafrost peat bogs and hydrates, abrupt increases in atmospheric methane, decomposition, peat decomposition, rainforest drying, forest fires, desertification. Other positive climate feedbacks include cloud feedback, ice–albedo feedback and gas release.

The main negative feedback or "cooling response" comes from the Stefan–Boltzmann law, the amount of heat removed from the Earth into space changes with the fourth power of the temperature of Earth's surface and atmosphere. This blackbody radiation or Planck response has been identified as "the most fundamental feedback in the climate system".[11]^: 19 Carbon cycle negative feedbacks act to remove carbon dioxide and methane from the system after their concentrations increase. These feedbacks include the response of oceans, chemical weathering, and primary production through photosynthesis.

Observations and modeling studies indicate that globally the positive feedbacks outweigh the negative feedbacks, indicating a net positive feedback to warming.[3]