Researching global warming's pause
23 September 2013 Last updated at 06:18 BST
Hundreds of scientists are holding talks in Stockholm on Monday on the latest major assessment of global warming.
The UN climate panel, known as the IPCC, reports every six years and its conclusions are meant to guide governments around the world.
A key challenge this time will be to explain why the rise in global temperatures has recently stalled.
Our science editor David Shukman reports.
Research video and graphics of Argo floats courtesy of University of California, San Diego