Climate change has seen parallel scientific and political processes
Assessing the science of climate change is the responsibility of the Intergovernmental Panel on Climate Change (IPCC), established by the United Nations in 1988.
It produces periodic reports on the state of play in climate science, gathering input from many hundreds of experts and developing a consensus on the current state of the climate, factors affecting it and possible future scenarios. The latest IPCC report, its fifth, was published in 2014.
World leaders gathered in Rio de Janeiro in 1992 at the first Climate Change Convention (or Earth Summit), agreeing to stabilise global greenhouse gas emissions.
There have been regular climate summits in the years since Rio, but the results have been mixed, with little agreement on universally applicable, legally binding targets. The Durban conference of 2011 was significant in that it paved the way towards establishing legally binding reduction targets for all countries by 2020.
Negotiations are now underway to form a new international agreement in 2015 for a single comprehensive global regime.