350 by mmatessa

Mike Matessa is summarizing what the experts are telling us.

"Coal is the largest reservoir of conventional fossil fuels, exceeding combined reserves of oil and gas. The only realistic way to sharply curtail CO2 emissions is to phase out coal use except where CO2 is captured and sequestered. Phase-out of coal emissions by 2030 keeps maximum CO2 close to 400 ppm, depending on oil and gas reserves and reserve growth... Improved agricultural and forestry practices offer a more natural way to draw down CO2. Deforestation contributed a net emission of 60±30 ppm over the past few hundred years, of which ~20 ppm CO2 remains in the air today. Reforestation could absorb a substantial fraction of the 60±30 ppm net deforestation emission. Carbon sequestration in soil also has significant potential. Biochar, produced in pyrolysis of residues from crops, forestry, and animal wastes, can be used to restore soil fertility while storing carbon for centuries to millennia. Biochar helps soil retain nutrients and fertilizers, reducing emissions of GHGs such as N2O. Replacing slash-and-burn agriculture with slash-and-char and use of agricultural and forestry wastes for biochar production could provide a CO2 drawdown of ~8 ppm or more in half a century... More rapid drawdown could be provided by CO2 capture at power plants fueled by gas and biofuels. Low-input high-diversity biofuels grown on degraded or marginal lands, with associated biochar production, could accelerate CO2 drawdown, but the nature of a biofuel approach must be carefully designed."

From Target Atmospheric CO2: Where Should Humanity Aim?, Hansen et al. (2008) 

 

Atmospheric CO₂ predictions from Hansen et al. (2008)

 

Strong grass-roots support for this proposal is shown by people at 7347 events in 188 countries participating in 10/10/10 Global Work Parties organized by 350.org.

 

"At first in the late 1980s and early 1990s, the number we routinely used was 550 parts per million CO2—mostly because it was double the pre-Industrial Revolution concentrations and hence easy to model... As time went on, it became clearer that the dangerous thresholds lay somewhere lower, and we began to use—almost interchangeably—450 parts per million, or 2 degrees Celsius... In the summer of 2007, though, with the rapid melt of Arctic ice, it became clear that we had already crossed serious thresholds. A number of other signs pointed in the same direction: the spike in methane emissions, likely from thawing permafrost; the melt of high-altitude glacier systems and perennial snowpack in Asia, Europe, South America and North America; the rapid and unexpected acidification of seawater. All of these implied the same thing: wherever the red line for danger was, we were already past it, even though the atmospheric concentration of CO2 was only 390 parts per million, and the temperature increase still a shade below 1 degree C. In early 2008, Jim Hansen and a team of researchers gave us a new number, verified for the first time by real-time observation (and also by reams of new paleo-climatic data). They said that 350 parts per million CO2 was the upper limit if we wished to have a planet “similar to the one on which civilization developed and to which life on earth is adapted.” That number is unrefuted; indeed, a constant flow of additional evidence supports it from many directions."

From Bill McKibben at 350.org

 

 

Atmospheric CO₂ data from processtrends.com

 

"Vision of young people is simple – we want to enjoy a stable climate that our parents grandparents have enjoyed, one without hundreds and thousands of refugees, resource scarcity, and natural disasters. The IPCC has stated that to give us a 50% chance of preventing two degrees warming we will require global emissions to be stabilized at 450ppm. Now, even venture capitalists would agree that 50% chance of return isn’t a worthwhile investment. Imagine the loss of this investment resulting in the destruction of our planet. My vision for the long term is that India makes to the 350ppm target, which gives us a strong chance at preventing runaway climate change. Clean technology will need a very strong presence to make this vision reality." - Deepa Gupta, Youth India