These are comparisons of cumulative global industrial CO2 emissions in the 21st century from three sources:
1) A Wigley and Raper paper in Science in 2001,
2) My response to the Wigley and Raper paper, with my (much better) predictions, published on my blog in 2006, and
3) The IPCC Representative Concentration Pathway (RCP) scenarios, including the "business as usual (see page 43)" RCP 8.5 scenario.
The meaning of the "5%", "50%", and "95%" designations is that there is a 5% chance, a 50% chance, and a 95% chance that the cumulative emissions in the 21st century will be less than the values given.
My 50% probability value was 712 GtC. The Wigley and Raper 50% probability value is 1385 GtC, and the RCP 8.5 "business as usual" is 1932 GtC. Current emissions are about 10GtC per year. If they plateau at this value for the next 10 years, then fall linearly to zero emissions in 2100, the total emissions for this century will be about 600 GtC...very close to my 712 GtC value, and miles away from the Wigley and Raper 1385 GtC value and the RCP 8.5 "business as usual value" of 1932 GtC.
In other words, I'm basically right, and they are way, way wrong. No surprise there.
P.S. What is surprising to me is that the Wigley and Raper paper was published in Science magazine, and it predicts that there is less than 1 in 20 chance (i.e., a 5% probability) that emissions in the 21st century will be more than 713 GtC. Why was this obviously wrong analysis never corrected? Isn't Science interested in...I don't know...science? Perhaps even more surprising is how in 2009 the RCP 8.5 scenario, with emissions of 1932 GtC, was labeled as "business as usual" and the so-called "scientific community" has never corrected that obvious nonsense.
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