The 1992 UN Framework Convention on Climate Change (Rio de Janeiro) commits signatories to prevent ‘dangerous anthropogenic interference with the climate system’, leaving unspecified the level of global warming that is to be considered dangerous. But keeping the average rise in global temperature below 2°C has become the focus of international efforts crystallized first in the Copenhagen climate change conference (2009) and reaffirmed in Cancun (2010). However, recent evidence shows that, there are slim chances that we can stay below this target and it is likely that temperature will rise above 4 degrees. It will have severe implications for societies around the world. The Durban conference (2011) recognized the need to limit the global warming to below 2°C, above pre-industrial levels. However, as the agreements in Durban do not propose remedial action before 2020, the risk of exceeding 2°C remains very high. The current pledges will require very high annual reduction rates after 2020, increasing the risk of not being able to restrict warming to less than 2 degrees. In other words, slow mitigation process at present will have to be hastened after 2020. Limiting warming to 2°C is critical for avoiding dangerous consequences and adaptive actions are needed to limit damage from climate change.