UN concludes on human origin of global warming[fr][de] 

"Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic (human) greenhouse gas concentrations," according to a summary  of the report, published on 2 February.

The assertion is stronger than the IPCC's previous 2001 conclusions which termed human responsibility as "likely", or equivalent to a 66% probability. The new wording "very likely" amounts to a probability of more than 90% in UN jargon.

The Intergovernmental Panel on Climate Change (IPCC ), an authoritative body of 2,500 scientists from more than 130 countries, ended a week-long closed-door meeting in Paris on 2 February.

It convened for the time since 2001 to hammer out a new consensus on the scientific foundations of climate change in a 20-page summary report discussed word-by-word: Climate Change 2007: The Physical Science Basis .

"The global increase in carbon dioxide concentrations are du primarily to fossil fuel use and land-use change, while those of methane and nitrous oxide are primarily due to agriculture," the report states. It adds that furhter warming during the 21st century is "very likely" and will "induce many changes in the global climate system".

Other main conclusions are:

• A rise in global temperature comprised between 1.8 and 4.0 degree Celsius in the 21st century (compared with 0.7 in the previous century);
• a recognition that global warming has caused stronger hurricanes, such as 2005's Katrina, stronger due to an increase in sea-surface temperatures, and;
• a "likely" estimation that polar ice melt that occured 125,000 years ago led to a rise in sea levels of 4 to 6 meters at temperatures which were 3 to 5°C higher than present.

The full climate science report will be released later in the year. In the meantime, three other chapters will be published which will look at the probable impacts of climate change, options for adapting to those impacts, and possible routes to reducing emissions of greenhouse gases.

In an interview, UK Environment Secretary David Miliband said: "The science of climate change, of global warming, is now unambiguous: the Earth is getting hotter, the weather is becoming more variable and this is due to our own industrial revolution," started in Britain during the 19th century.

In response to the challenge, the European Commission has urged EU states to embark on a second "post-industrial revolution" that would steer it towards a low-carbon economy by 2050. 

In its boldest proposal yet, it said that EU nations should aim for a 20% cut in GHG by 2020, a target that would be raised to 30% if other industrialised nations were to follow suit (EurActiv 11/01/07).