Activities of WCRP Projects and Working Groups contribute to the issue of understanding, attributing or predicting the consequences of human activities in climate change.
Quantifying the effects of ozone depletion and recovery arising from anthropogenic halogens, together with those of changes in other greenhouse gases, is of great importance for human welfare. Achieving this goal requires evaluation of the impact of stratospheric ozone depletion and recovery on tropospheric climate as well as elucidating the effects of climate change on the evolution of ozone itself. The SPARC program has activities that address aspects of all of these issues. Those that are most directly relevant to the WCRP Anthropogenic Climate Change (ACC) cross-cutting are:
WGCM is charged with coordinating experimentation with coupled models that are aimed at understanding natural climate variability on decadal to centennial time scales and its predictability, and at predicting the response of the climate system to changes in natural and anthropogenic forcing. The WCRP Climate Model Intercomparison Project (CMIP) is a major WGCM contribution to the WCRP Anthropogenic Climate Change (ACC) crosscutting topic.