I'm sure there's more recent material but as jethro outlines, the Sun's effect has previously been relegated as it has been perceived as a constant allowing greenhouse gases to take a more prominent role.
http://news.bbc.co.uk/1/hi/7327393.stm
"Scientists have produced further compelling evidence showing that modern-day climate change is not caused by changes in the Sun's activity."
http://www.newscientist.com/article/dn11650-climate-myths-global-warming-is-down-to-the-sun-not-humans.html
"The 2007 IPCC report halved the maximum likely influence of solar forcing on warming over the past 250 years from 40% to 20%."
"Similarly, there is no trend in direct measurements of the Sun's ultraviolet output and in cosmic rays. So for the period for which we have direct, reliable records, the Earth has warmed dramatically even though there has been no corresponding rise in any kind of solar activity."
http://www.giss.nasa.gov/research/news/19990408/
"According to Shindell, the new study also confirms that changing levels of energy from the sun are not a major cause of global warming."