Sunday, November 29, 2015

CONFERENCIA SOBRE EL CAMBIO CLIMATICO EN PARIS

Pre-Judging Paris by Bjørn Lomborg - Project Syndicate


COPENHAGEN
– The United Nations Climate Change Conference in Paris later this
month is being billed as an opportunity to save the planet. It is no
such thing. As I show in a new peer-reviewed paper, even if successful, the agreement reached in Paris would cut temperatures in 2100 by just 0.05° Celsius. The rise in sea level would be reduced by only 1.3 centimeters. 

This may seem surprising: we constantly hear how every country has made important commitments to reduce CO2 emissions – the so-called “Intended Nationally Determined Contributions,” or INDCs. According to the UN’s climate chief, Christiana Figueres,
“the INDCs have the capability of limiting the forecast temperature
rise to around 2.7ºC by 2100, by no means enough but a lot lower than the estimated four, five, or more degrees of warming projected by many prior.”

The expected rise of 4.5°C is based on almost 10,000 gigatons (Gt, or billion tons) of CO2 emitted during this century, with all other greenhouse gasses converted to CO2 equivalents. But nobody actually believes this figure – even the UN Environment Programme estimates that with absolutely no climate policies, we would emit 7,750Gt, which might lead to a 3.8°C rise. So, the extra 0.7°C rise is simply made up: climate policies can’t take credit for reducing it, because it was never going to happen in the first place. 


Keeping temperature rises to 2.7°C will require the world to restrict emissions to about 4,700Gt. So, in order to live up to Figueres’ promise, we should expect Paris to cut about 3,000Gt. It will not. 


Figueres’s own organization estimates that the total reduction promised from 2016 to 2030 will amount to 29-33Gt, or 1% of  what is needed to get to 2.7°C. Achieving the other 99% is based on the aspiration that, while little will happen from 2016-2030, right after that countries will step up and begin dramatic emissions cuts. Recent history renders this implausible.


Versión en español

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