“PM2.5” seems an odd and wonky term for the blogosphere to take up, but that is precisely what has happened in China in recent weeks. It refers to the smallest solid particles in the atmosphere—those less than 2.5 microns across. Such dust can get deep into people’s lungs; far deeper than that rated as PM10. Yet until recently China’s authorities have revealed measurements only for PM10. When people realised this, an online revolt broke out. Such was the public pressure that authorities caved in, and PM2.5 data are now being published for Beijing and a handful of other cities.

With global efforts to reduce carbon dioxide emissions stalled, the United States and five other countries are starting a new program to cut other pollutants — including methane, soot and hydrofluorocarbons — that contribute to global warming.

Global carbon dioxide emissions from burning fossil fuels have increased by 49 per cent in the last two decades, according to the latest figures by an international team, including researchers at the Tyndall Centre for Climate Change Research, University of East Anglia.

Published Dec. 4 in the journal Nature Climate Change, the new analysis by the Global Carbon Project shows fossil fuel emissions increased by 5.9 per cent in 2010 and by 49 per cent since 1990 -- the reference year for the Kyoto protocol.

The global output of heat-trapping carbon dioxide has jumped by a record amount, according to the US department of energy, a sign of how feeble the world's efforts are at slowing man-made global warming.

The figures for 2010 mean that levels of greenhouse gases are higher than the worst case scenario outlined by climate experts just four years ago.

"The more we talk about the need to control emissions, the more they are growing," said John Reilly, the co-director of MIT's Joint Program on the Science and Policy of Global Change.

On Aug. 8, 1975, geoscientist Wallace Smith Broecker published "Are We on the Brink of a Pronounced Global Warming?" in the journal Science, the first time the iconic phrase "global warming" was used in a scientific paper.