Cambio climático: aún hay esperanzas.

http://www.ft.com/cms/s/0/db345484-c2e2-11e3-94e0-00144feabdc0.html#ixzz2ylL2VwBh

UN climate study: still time to save the world

By Clive Cookson in London

Disastrous effects of global warming can still be avoided, the world’s leading climate scientists say, but only by making a concerted international effort to cut carbon emissions through heavy investment in renewable and nuclear energy sources.

The UN Intergovernmental Panel on Climate Change’s third report of a trio on global warming, released on Sunday, focuses on “mitigation” – how to fight global warming by limiting the build-up of carbon dioxide and other greenhouse gases in the atmosphere.

The key objective is to keep the average worldwide temperature rise below 2C, the internationally agreed target that would avoid catastrophic global change.“This is a message of hope,” Ottmar Edenhofer, co-chairman of the group that wrote the report, told the FT. “It can be done, but it means moving away from business as usual to avoid dangerous interference with the climate system.”

The report, based on 1,200 scenarios from scientific papers analysed by 31 modelling teams around the world, concludes that global greenhouse gas emissions must be cut by between 40 and 70 per cent compared with 2010 by mid-century. By 2100 there should be minimal net emissions – or even “negative emissions”, which means extracting carbon dioxide from the atmosphere by growing trees on a large scale or scaling up technology still in the early stages of research today.

Large changes in investment patterns, particularly in the energy industries, will be required to achieve the 2C warming goal. The report estimates that investment in power generation from conventional fossil fuels should fall $30bn a year while investment in low-carbon plants (nuclear, renewables and carbon capture) rises $147bn a year. Total global annual investment in the energy system is about $1,200bn today.

In addition, the IPCC says investment to improve energy efficiency in transport, buildings and industry needs to rise $336bn a year.

The economics of mitigation are a particularly controversial issue in climate policy. The report acknowledges that estimates of the net costs vary widely according to assumptions, model design and technologies available.

But it concludes that an ambitious fight against climate change will reduce annualised economic growth by somewhere between 0.04 and 0.14 percentage points, with 0.06 per percentage points the most likely figure. This would leave global consumption in 2050 just 3.4 per cent lower than under the “business as usual” scenario.

To solve that problem, we need to put a price on carbon, which reflects the emerging scarcity of disposal space for carbon dioxide in the atmosphere,” he added.The most immediate need, said Mr Edenhofer, is to end “the renaissance of fossil fuels, particularly coal for power generation in China, India and elsewhere, that we have seen over the past decade or so.

The report received a generally warm welcome from environmental groups and climate scientists who were not directly involved in its production.

Samantha Smith of WWF International said: “Any investor who looks at this report will have to reach an obvious conclusion: it’s time to pull your money out of dirty fossil fuels and put it into renewable energy and energy efficiency.”

The final stage in the IPCC fifth assessment round will be the release in October of a “synthesis report” that pulls together this analysis with the two previous reports on the physical science of climate change and its impacts.

At the same time, the political process of trying to reach a binding international agreement will continue, with a UN climate summit scheduled for September in New York. The next milestone will be a meeting in Paris at the end of 2015, which is supposed to agree comprehensive and legally binding measures to fight climate change on a global basis.

“International co-operation is key,” said Mr Edenhofer. “Putting in place the international institutions need for co-operation is a challenge in itself.”