The Fifth Assessment Report (AR5) from the United Nations Intergovernmental Panel on Climate Change is now underway and is expected to be finalized in 2014. Here is the summary for policymakers:

A concise overview was published as the Summary for Policymakers on 27 September 2013. The level of confidence in each finding was rated on a confidence scale, qualitatively from very low to very high and, where possible, quantitatively from exceptionally unlikely to virtually certain (determined based on statistical analysis and expert judgement). The principal findings were:

Warming of the atmosphere and ocean system, and associated impacts such as sea level change have certainly occurred since 1950. Many of these metrics have changed at rates unprecedented in the historical record.
It is likely that 1983—2013 was the warmest 30-year period for 1400 years.
It is virtually certain the upper ocean warmed from 1971 to 2010.
Ocean warming accounts for 90% of the energy accumulation between 1971 and 2010.
Greenland and Antarctic ice sheets have been losing mass in the last two decades.
Mean 1901—2010 sea level rise was stated as 19 ± 2 cm.
Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent.
Concentration of greenhouse gases in the atmosphere have increased to levels unprecedented on earth in 800,000 years. The rate of increase over the 20th century is the greatest known for 22,000 years (very high confidence).
Total radiative forcing of the earth system, relative to 1750, is positive and the most significant driver is the increase in CO2’s atmospheric concentration.
It is extremely likely human influence has been the dominant cause of observed warming since 1950, the level of confidence having increased since the fourth report.
Continued emissions will lead to further warming and changes in the climate system.