Using this graphic and referring to it is encouraged, and please use it in presentations, web pages, newspapers, blogs and reports.
For any form of publication, please include the link to this page and give the cartographer/designer credit (in this case Philippe Rekacewicz, UNEP/GRID-Arendal)
Climate change 1995, The science of climate change, contribution of working group 1 to the second assessment report of the intergovernmental panel on climate change, UNEP and WMO, Cambridge university press, 1996
Uploaded on Wednesday 22 Feb 2012
Radiative forcing - energy balances and the greenhouse effect
Philippe Rekacewicz, UNEP/GRID-Arendal
Radiative forcing is the change in the balance between radiation coming into the atmosphere and radiation going out. A positive radiative forcing tends on average to warm the surface of the Earth, and negative forcing tends on average to cool the surface. The figure shows estimates of the globally and annually averaged anthropogenic radiative forcing (in Wm-2) due to changes in concentrations of greenhouse gases and aerosols from pre-industrial times to present day and to natural changes in solar output from 1850 to present. The height of the rectangular bar indicates a mid-range estimate of the forcing and the error bars show the uncertainty range. Confidence level shows the author's confidence that the actual forcing lies within the given error range. Note: forcing associated with stratospheric aerosols resulting from volcanic eruptions is not shown because it is very variable over this time period.