Rate of Global Temperature Change

An article in Science on 7 March 2013 reports the use of 73 ice and sediment cores from around the world to reconstruct Earth’s temperature back 11 300 years to the end of the last ice age.  It shows a warmer planet now than has been the case during 70-80% of that time period.  The last 5000 years showed an average 0.7 degree C cooling, whereas the last 100 years showed an average 0.7 degree C temperature rise. "The Earth's climate is complex and responds to multiple forcings, including carbon dioxide and solar insolation," says one of the authors.  "Both changed very slowly over the past 11 000 years. But in the last 100 years, the increase in carbon dioxide through increased emissions from human activities has been significant. It's the only variable that can best explain the rapid increase in global temperatures."
Source: http://www.nsf.gov/news/news_summ.jsp?cntn_id=127133&WT.mc_id=USNSF_51&WT.mc_ev=click