Attribution of climate change is the effort to scientifically show which mechanisms are responsible for observed changes in Earth’s climate. To determine anthropogenic attribution, known internal climate variability and natural external forcings need to be ruled out. Therefore, a key approach is to use computer modelling of the climate system to determine unique “fingerprints” for all potential causes. By comparing these fingerprints with observed patterns and evolution of climate change, and the observed history of the forcings, the causes of the observed changes can be determined. For example, solar forcing can be ruled out as major cause because its fingerprint is warming in the entire atmosphere, and only the lower atmosphere has warmed, which is what is expected from greenhouse gases (which trap heat energy radiating from the surface). Attribution of recent climate change shows that the primary cause is greenhouse gases, and secondarily land-use changes, and aerosols and soot.
Author: Bianca Carli