<Li> It is extremely likely that human influence has been the dominant cause of observed warming since 1950, with the level of confidence having increased since the fourth report . </Li> <Li> IPCC pointed out that the longer we wait to reduce our emissions, the more expensive it will become . </Li> <Ul> <Li> It is likely (with medium confidence) that 1983--2013 was the warmest 30 - year period for 1400 years . </Li> <Li> It is virtually certain the upper ocean warmed from 1971 to 2010 . This ocean warming accounts, with high confidence, for 90% of the energy accumulation between 1971 and 2010 . </Li> <Li> It can be said with high confidence that the Greenland and Antarctic ice sheets have been losing mass in the last two decades and that Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent . </Li> <Li> There is high confidence that the sea level rise since the middle of the 19th century has been larger than the mean sea level rise of the prior two millennia . </Li> <Li> Concentration of greenhouse gases in the atmosphere has increased to levels unprecedented on earth in 800,000 years . </Li> <Li> Total radiative forcing of the earth system, relative to 1750, is positive and the most significant driver is the increase in CO's atmospheric concentration . </Li> </Ul> <Li> It is likely (with medium confidence) that 1983--2013 was the warmest 30 - year period for 1400 years . </Li>

Ipcc’s fifth assessment report (ar5)