Re:Earth may temporarily pass dangerous 1.5 C warming limit ...
by kurthr on Monday September 14, 2020 @02:22AM
(#24467354)
The half life of CO2 in the atmosphere is about 30 years (2.5%/yr). We're currently at ~400ppm, whereas before industrialization we were at ~250 (there are other sources). So yes, if we stopped anthropogenic CO2 we would very likely avoid a 1.5C increase.
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Re:Earth may temporarily pass dangerous 1.5 C warming limit ...
by GeoAtreides on Monday September 14, 2020 @02:50AM
(#24467506)
"half life of CO2 in the atmosphere" is a bit misleading, (most|some) people will think it means the quantity of CO2 in the atmosphere halves every 30 years. That is false.
This NASA link says CO2 stays in the atmosphere for hundreds of years: https://climate.nasa.gov/news/2915/the-atmosphere-getting-a-...
And this site: https://www.skepticalscience.com/co2-residence-time.htm
explains that while the individual molecule CO2 hangs around the atmosphere for 3-4 years, it's then merely exchanged with one in the oceans (or maybe one in a rotting tree).
On this study: https://scholars.unh.edu/cgi/viewcontent.cgi?referer=https:/...
on page 4 (shown 25 on the page), you can see the box model of the global carbon cycle. Halflife refers on how long the a CO2 molecule spends in a given box.
Re:Earth may temporarily pass dangerous 1.5 C warming limit ...
by nostrademons on Monday September 14, 2020 @02:24AM
(#24467374)
There are other second-order effects that continue, eg. reduced albedo as the polar ice melts, methane emissions as the permafrost thaws, increased weathering of carbonates.