The world's top scientists have given their clearest warning yet of the severe and irreversible impacts of climate change.
The United Nations Intergovernmental Panel on Climate Change (IPCC) has released its synthesis report, a summary of its last three reports.
It warns greenhouse gas levels are at their highest they have been in 800,000 years, with recent increases mostly due to the burning of fossil fuels.
"Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems," the report said.
There's a brief summary of conclusions from the IPCC Fifth Assessment Synthesis Report at: http://www.ipcc.ch/report/ar5/