We are often asked if global temperatures are going to fall or continue to rise. Based on thousands of years of paleo-temperature data, the question is not "if" but "when."
Our favorite temperature reconstruction of the last 2,000 years was compiled by Dr. Craig Loehle, who avoided using problematic tree ring data. This shows clearly that the modest warming of the last 300 years is simply a recovery to more normal temperatures of the last several thousand years from what was likely the coldest temperatures of the last 10,000 years in the Little Ice Age.
Loehle C, McCulloch JH (2008b) Correction to: A 2000-Year Global Temperature Reconstruction Based On Non-Tree Ring Proxies. Energy & Environment, Vol 19, No 1