The Intergovernmental Panel on Climate Change (IPCC) meets this week in Sweden to thrash out a critical report on global warming.
Scientists will underline, with greater certainty than ever, the role of human activities in rising temperatures.
But many governments are demanding a clearer explanation of the slowdown in temperature increases since 1998.
One participant told BBC News that this pause will be a "central piece" of the summary.
Researchers from all over the world work with the IPCC to pore over thousands of peer-reviewed studies and produce a summary representing the current state of climate science.
Governments are demanding a clear explanation of what are the possible causes of this factor”
Its previous report in 2007 was instrumental in helping the panel share the Nobel Peace Prize that year.
A new Summary for Policymakers on the physical sciences, the first of three parts that make up a report to be released over the next 12 months, will be published in Stockholm on Friday.
It will focus on the science underlying changes in temperature in the atmosphere, the oceans and at the poles.
New estimates will be given for the scale of global warming and its impact on sea levels, glaciers and ice sheets.
The top graph shows the slowdown in warming of the global temperature since 1998. The bottom graph indicates the temperature trend for the oceans which is intricately related to the air temperature. The scientific panel is calling this a pause in global warming. 15 years is a relatively short time in climatology and one should be hesitant to make any conclusions based on that short a term. If it continues for another 15 years, then the IPCC has a real credibility problem. Nevertheless, the panel will be hard-pressed to explain this 'pause' and we can expect some heated arguments before they come to a statement they can agree on, if they can find a statement they can agree on.