How Much Is Too Much?: Estimating Greenhouse Gas Emissions

[OKIsItJustMe]

http://www.scientificamerican.com/article.cfm?id=limits-on-greenhouse-gas-emissions&sc=CAT_INNO_20090501

April 29, 2009 | 47 comments

How Much Is Too Much?: Estimating Greenhouse Gas Emissions

Two new studies aim to quantify limits on the amount of greenhouse emissions necessary to avoid dangerous global warming

By David Biello

To avoid catastrophic climate change, the world will need to emit less than one trillion metric tons of carbon between now and 2050, according to two new papers published in Nature today. In other words, there is only room in the atmosphere to burn or vent less than one quarter of known oil, natural gas and coal reserves.

Atmospheric concentrations of carbon dioxide have reached 386 parts per million—and rising, because every year, human activity spews more than 30 billion metric tons of CO2. So far, that's led to warming of roughly 0.8 degree Celsius (1.4 degrees Fahrenheit). The question is: How much more can we safely emit? The two new papers attempt an answer.

"There is a simple and predictable relationship between the total amount of carbon injected into the atmosphere and peak projected warming," says physicist Myles Allen of the University of Oxford in England and lead author of http://www.nature.com/nature/journal/v458/n7242/full/nature08019.html">one of the studies. "Releasing a trillion (metric) tons of carbon into the atmosphere may cause a most likely peak warming of 2 degrees C (3.6 degrees F), which many identify as the danger point." An average temperature rise of 2 degrees C or lower has been adopted by the European Union and other countries—110 in all—as a goal for any treaty to control climate change, and has been identified by scientists, including the authors of the U.N. Intergovernmental Panel on Climate Change report, as a point at which most climate changes become damaging.

But CO2—and the carbon at its molecular core—is not the only greenhouse gas. Others—ranging from methane to hydrofluorocarbons (HFCs)—"could contribute as much as 10 to 40 percent of the warming induced by CO2 alone," says climatologist Malte Meinshausen of the Potsdam Institute for Climate Impact Research (PIK) in Germany, lead author of the http://www.nature.com/nature/journal/v458/n7242/full/nature08017.html">second study appearing in Nature. That drops the overall budget for atmospheric emissions to roughly 750 billion metric tons of carbon between the years 2000 and 2050. "To limit the risk to a one-in-four chance , then total CO2 in the first half of the 21st century has to be kept below (one trillion) metric tons.

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[JohnWxy]

1. Shit!

http://www.eia.doe.gov/oiaf/ieo/scdc.html


According to eia we are increasing our emissions of CO2 about 2.1% per yr. So we would have to reduce our production of CO2 by 2.1% per yr just to get to zero growth per yr. And then reduce our rate of production by 3% per year. Total swing of 5.1% to achieve a 3% reduction per year.

While everyone wants economic growth too.