Understanding and Attributing Climate Change
- Climate change detection and attribution
- Detection - determinating that observed change highly unlikely to have been caused by internal climate variability
- Attribution - establishing the most likely causes of detected change
- External forcing mechanisms, both natural and anthropogenic, considered as potential causes of climate change
- Natural
- Solar variability
- Volcanic activity
- Anthropogenic
- Greenhouse gas increases
- Tropospheric and stratospheric ozone changes
- Sulphate aerosol changes
- Other aerosol changes
- Land cover changes
- Estimates of internal variability usually obtained from long coupled model control runs
- Relative importance of various forcing mechanisms estimated by differences in spatial and temporal patterns (fingerprints)
- Understanding past climate change
- Pre-industrial climate change
- Cooler conditions during last glacial maximum (21 kyr) related to increased albedo and decreased carbon dioxide
- Warmer, wetter conditions during mid-Holocene optimum (8 kyr) related to higher amplitude annual cycle
- Climate variations over last 1,000 years of pre-industrial period probably related to volcanic activity and solar variability
- Twentieth Century climate change
- Estimates of climate sensitivity
- Equilibrium climate sensitivity
- Overall evidence of anthropogenic climate change