Others however disagree with Solanski et al. on whether...
The sun drives the global climate
Others however disagree with Solanski et al. on whether sunspot activity correlates with temperature changes and on whether we are in the most active period for several thousand years. Muscheler et al. The link between the visually based sunspot numbers and solar-modulation parameter is neither straightforward nor yet understood, and also that solar modulation must have reached or exceeded today’s magnitudes three times during the past millennium... The reconstruction by Solanki et al. implies generally less solar forcing during the past millennium than in the second part of the twentieth century, whereas our reconstruction indicates that solar activity around AD 1150 and 1600 and in the late eighteenth century was probably comparable to the recent satellite-based observations. Both Muscheler and Solanski agree that "solar activity reconstructions tell us that only a minor fraction of the recent global warming can be explained by the variable Sun."[[Raimund Muscheler, Fortunat Joos, Simon A. Müller, Ian Snowball, 'How unusual is today’s solar activity?', Nature, 431, 1084–1087 (2004), http://www.cgd.ucar.edu/ccr/raimund/publications/Muscheler_et_al_Nature2005.pdf%5D%5D In other words even if the sun is having some effect the majority of climate change is still being caused by other factors of which the most likely is humans. Influence of the Sun does not seem to be so great on global warming trends. Surprisingly, even though average temperatures are still rising(the 2000s are on track to be nearly 0.2°C warmer than the 1990s. And that temperature jump is especially worrisome since the 1990s were only 0.14°C warmer than the 1980s[[http://data.giss.nasa.gov/gistemp/graphs/]].), solar activity is at a minimum, as reported by NASA in April 2009: NASA, April 1, 2009 2008 was a bear. There were no sunspots observed on 266 of the year's 366 days (73%). To find a year with more blank suns, you have to go all the way back to 1913, which had 311 spotless days: plot. Prompted by these numbers, some observers suggested that the solar cycle had hit bottom in 2008. Maybe not. Sunspot counts for 2009 have dropped even lower. As of March 31st, there were no sunspots on 78 of the year's 90 days (87%). It adds up to one inescapable conclusion: "We're experiencing a very deep solar minimum," says solar physicist Dean Pesnell of the Goddard Space Flight Center. "This is the quietest sun we've seen in almost a century," agrees sunspot expert David Hathaway of the Marshall Space Flight Center. [[http://science.nasa.gov/headlines/y2009/01apr_deepsolarminimum.htm]]