British chemist Robert Watson had strict instructions when he sat down to write the opening chapter of the first U.N. scientific overview of climate change in 1990: ¡°Keep it short.¡±

On Monday, the sixth set of reports by the same U.N. panel hit a record length of more than 10,000 pages, with the release of a third section of almost 3,000 pages on solutions to climate heating, showing it is ¡°now or never¡± to head off the worst.

By contrast, in 1990, the initial report series by the Intergovernmental Panel on Climate Change (IPCC) totaled a relatively modest 1,000 pages.