Independent summary for policymakers

Fellow of the American Meteorological Society, Fellow of the American Geophysical Union, Fellow of the Royal Meteorological Society, Fellow of the American Association for the Advancement of Science. [...] The ISPM summarizes the most important elements of the science, regardless of whether it is given the same level of focus in the IPCC s Summary documents. [...] Much of the text herein follows wording as set by IPCC Lead and Contributing Authors in the Second Order Draft as of the close of the scientific review period on June 2, 2006, on the assumption that this will also be the wording in the final draft. [...] Since the Third Assessment Report, new studies have confirmed and advanced the plausibility of indirect effects on the climate system involving the modification of the stratosphere by solar UV irradiance variations (and possibly by solar-induced variations in the overlying mesosphere and lower thermosphere), with subsequent dynamical and radiative coupling to the troposphere. [...] The ACE is proportional to the square of the wind speed and the PDI is proportional to the wind speed cubed.