The Carbon Cycle Behind Net Zero

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Жыл бұрын

What happens to carbon dioxide after we emit it? Half is absorbed within a year or two by plants and the oceans, the rest, in effect, stays in the atmosphere. So, does that mean we have to halve emissions to stop concentrations rising? Unfortunately, no.
Despite the vast reserves of carbon dissolved in the oceans, carbon dioxide released by burning fossil fuels does not get diluted away, but makes an indelible mark on climate for hundreds of thousands of years.
A lecture by Myles Allen recorded on 7 March 2023 at Barnard's Inn Hall, London.
The transcript and downloadable versions of the lecture are available from the Gresham College website:
www.gresham.ac.uk/watch-now/c...
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Пікірлер: 20

@MrAytch Жыл бұрын

Thank you to all involved in this presentation. The attention required was well rewarded!

@GreshamCollege Жыл бұрын

Glad you enjoyed it!

@DeeChand-zz9mf 2 ай бұрын

Amazing understanding and explanation of concepts

@dhruvtripathi8420 9 ай бұрын

Thank you for all the energy you put into such a detailed and wonderful presentation. Especially appreciate how you give credit to all the scientists whose work you cited. It's multiple lifetimes of research which has given us the knowledge and insight into the crisis we have today. Thank you once again for bringing it all together so comprehensively.

@whatabouttheearth 8 ай бұрын

2:50 that blinking you see in South America is the fluctuation between day and night, so between photosynthesis and respiration. So in that one video, at the same time you can see the daily fluctuation of CO2 from plants (due to the fluctuation of day photosynthesis and night respiration), and the yearly fluctuation of CO2 from plants (due to the seasons). Really cool! 😎

@xenocampanoli815 Жыл бұрын

One thing that seems to always be left out is that when the higher carbon waters in the deep ocean re-emerge some hundreds of years in the future when there is presumably more warming, suddenly the surface warming will accelerate exhausting carbon.

@TheMrCougarful Жыл бұрын

This was well done. I'm a biologist, the constant narrative about how the biosphere will solve the problem for us is simply 100 percent incorrect. On the timescales of global system dynamics, carbon capture by plants is essentially zero. Plants are part of the carbon cycle. CYCLE. This is not the solution you suppose it to be.

@whatabouttheearth 8 ай бұрын

After 49:50 he directly said that putting carbon into the biosphere as a sink is not equivalent with carbon coming out of the geosphere.

@philclancaster Жыл бұрын

Really well presented and clear, thanks

@GreshamCollege Жыл бұрын

Glad it was helpful!

@xenocampanoli815 Жыл бұрын

Given the deep oceans hold massive amounts, but get circulated every so often, it seems that overturning period, presumably something between 100 and 1000 years, runs one time after recapture is turned off, we will then be doomed to all that repository's worth, which I suspect is a whole lot.

@whatabouttheearth Жыл бұрын

"Radioactive Carbon 13"? What? C12 and C13 are stable, C14 is the radioactive isotope. And we are seeing an increase in the C12/C13 ratio found in plants (more "lighter" C12 than "heavier" C13) but not a relative increase of radioactive C14. This is because it is ancient plants that are majority of fossil fuel CO2 (coal) so it no longer has the radioactive C14, neither does petroleum (fossil plankton/algae).

@xenocampanoli815 Жыл бұрын

I'm afraid the pipes example, which is helpful to those who think logically, is useless for helping those who are deniers to understand the problem, because they are unable to think logically with adequacy to getting the message. They will just ridicule the example out of ignorance.

@no-one-knows321 Жыл бұрын

Like to know what the ideal earth temperature is?

@whatabouttheearth Жыл бұрын

There is no "ideal earth temperature", it is relative to the climate that the extant organisms of the current biosphere evolved in. Natural atmospheric CO2 (one of many greenhouse gasses) rates have been low for about a million years, extremely lower than say, in the Mesozoic era when the dinosaurs and first mammals existed, but the lifeforms that exist now have evolved within a slow natural change of atmospheric CO2 levels, in that context of low levels of atmospheric CO2. Natural climate change does happen of course but it usually occurs over hundreds of thousands or millions of years, certainly not at the rapid rate humans have been changing it since the industrial revolution.