Natural phenomena such as solar variation combined with volcanoes probably had a small warming effect from pre- industrial times to 1950 and a small cooling effect from 1 950 onward.  These basic conclusions have been endorsed by at least 30 scientific societies and academies of science, including all of the national academies of science of the major industrialized While individual scientists have voiced disagreement with these the overwhelming majority of scientists working on climate change agree with the Epic’s main conclusions. 1 3] Climate model projections summarized by the EPIC indicate that average global surface temperature will likely rise a further 1. 1 to 6. 4 co (2. 0 to 11. 5 OF) during the twenty-first century.  This range of values results from the use of differing scenarios of future greenhouse gas emissions as well as models with differing climate sensitivity. Although most studies focus on the period up to 21 00, warming and sea level rise are expected to continue for more than a housing years even if greenhouse gas levels are stabilized.
The delay in reaching equilibrium is a result of the large heat capacity of the oceans.  Increasing global temperature is expected to cause sea levels to rise, an increase in the intensity of extreme weather events, and significant changes to the amount and pattern of precipitation, likely leading to an expanse of tropical areas and increased pace of desertification. Other expected effects of global warming include changes in agricultural yields, modifications of trade outs, glacier retreat, mass species extinctions and increases in the ranges of disease vectors.
Remaining scientific uncertainties include the amount of warming expected in the future, and how warming and related changes will vary from region to region around the globe. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions, but there is ongoing political and public debate worldwide regarding what, if any, action should be taken to reduce or reverse future warming or to adapt to its expected consequences.