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James Hansen explains that CO2 climate sensitivity is much worse than the numbers decision makers are using (www.columbia.edu)
submitted 1 year ago by to c/collapse@lemmy.zip
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Hansen and team's research finds climate sensitivity is at least 4.5C for a doubling of CO2 with 99% certainty. Too bad COPS is using 3.0 like it is gospel. For some perspective, the CO2 baseline is around 285, and we're up to 425 (we're only 145 away from doubling and that's ignoring increases in fun things like methane and nitrous oxide). The amount to get to the doubled value is roughly the increase we have experienced in my lifetime, so it is not as far away as it might seem.

I guess I should invest in air conditioned farming.

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[–] [S] 5 points 1 year ago (5 children)

It is an interesting question. When I look at the data, the RCP 8.5 scenario looks like the closest fit, but people insist that it is unrealistic and off the table. Is it some sort of cognitive dissonance defense mechanism?

The "planners" seem to be factoring in carbon capture technology that is not yet extant and that may never be extant.

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  • [–] 4 points 1 year ago (2 children)

    In the IPCC reports, Carbon Capture +Storage is a fairly significant variable.

    https://www.ipcc.ch/site/assets/uploads/2018/03/srccs_summaryforpolicymakers-1.pdf

    Under heading #19

    1. In most scenarios for stabilization of atmospheric greenhouse gas concentrations between 450 and 750 ppmv CO2 and in a least-cost portfolio of mitigation options, the economic potential23 of CCS would amount to 220– 2,200 GtCO2 (60–600 GtC) cumulatively, which would mean that CCS contributes 15–55% to the cumulative mitigation effort worldwide until 2100, averaged over a range of baseline scenarios.

    15% at the low end and 55% at the high end. And we haven't developed this technology or begun to scale it yet.

    I think it's almost like Ponzi scheme accounting where your books balance as long as you get new investment in the future. We are planning on overshooting the carbon in the atmosphere and then doing negative emissions at some point later in the century.

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