The work of thousands of climate scientists is being debated and assessed this week in Brussels during a meeting of the UN Intergovernmental Panel on Climate Change.
The final report, six years in the making, forecasts the impact of climate change, and continued rising temperatures. Rajendra Pachauri chairs the panel.
"You have to assess the impact of climate change, those areas which are most vulnerable to those impacts and how we might be able to adapt to those changes. So I think from a human point of view this is most critical. We need to understand what climate change means for us in our own lives and how it is going to effect both natural as well as social systems."
The conclusion of the delegates representing more than 120 countries is that climate change is having a more devastating impact on developing nations, and poorer citizens within richer countries. Rising temperatures are already affecting some regions, and they are experiencing severe water shortages and hunger.
"The issues that are most critical are for instance, sea level rise -- what it means to people living in coastal areas, small island states, melting at the glaciers, and finally I think it is also essential to see what climate change means to all in terms of impacts on all living species -- that's both the plant and animal kingdom, because that has direct linkages with human beings."
Belgium Prime Minister Guy Verhofstadt said:
"I think the most important thing here is the unity of vision that we need on the issue of climate change. Because until now there was still this discussion between scientists, those who were saying that there was a problem, those who were saying 'Oh no, it's not so big a problem.' And I think that what we need now is political action."
A position echoed by Martin Hiller of the World Wildlife Fund
"Governments need to do two things. They need to get emissions down and they need to prepare for a massively changing climate."
This is the second of four reports from the Intergovernmental Panel on Climate Change. The first in February updated the science of climate change. It concluded with near certainty that global warming is caused by human activity and is likely to continue.