this post was submitted on 01 Aug 2023
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Climate - truthful information about climate, related activism and politics.

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Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.

As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades: Graph of temperature as observed with significant warming, and simulated without added greenhouse gases and other anthropogentic changes, which shows no significant warming

How much each change to the atmosphere has warmed the world: IPCC AR6 Figure 2 - Thee bar charts: first chart: how much each gas has warmed the world.  About 1C of total warming.  Second chart:  about 1.5C of total warming from well-mixed greenhouse gases, offset by 0.4C of cooling from aerosols and negligible influence from changes to solar output, volcanoes, and internal variability.  Third chart: about 1.25C of warming from CO2, 0.5C from methane, and a bunch more in small quantities from other gases.  About 0.5C of cooling with large error bars from SO2.

Recommended actions to cut greenhouse gas emissions in the near future:

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[–] silence7@slrpnk.net 0 points 1 year ago (1 children)

The big ones we expect to play a role in the next few decades are in there though. That's enough to be pretty useful.

[–] Redacted@lemmy.world 1 points 1 year ago (1 children)

Pretty useful, in that they predict warming but not necesarily accurate.

I disagree, we do not know how well feedbacks are modelled or even if the models include all significant feedbacks. Correct me if you've found anything that contadicts these:

  • The albedo effect problem you mentioned is likely to happen faster than predicted as the latent heat of melting isn't considered. The heat it requires to melt all that ice will instead heat the water around the remaining ice at a much higher rate.

  • IPCC doesn't account for the aerosol cooling effect. If we cut our emissions there would likely be a rapid warming of 0.5-1.0°C within a couple of years as particulates in the air are blocking less sunlight.

  • The ice sheets don't melt at a steady rate. Last time this much carbon dioxide was in the atmosphere they ended up retreating 600m per day which should affect predictions.

  • Not strictly a feedback loop but worth mentioning... The earth contains less than 20% of the copper needed to produce the renewables required to replace fossil fuels over the next 20 years, about 20% of the required nickel and less than 2.5% of the required lithium.

[–] silence7@slrpnk.net 1 points 1 year ago

The albedo effect problem you mentioned is likely to happen faster than predicted as the latent heat of melting isn’t considered. The heat it requires to melt all that ice will instead heat the water around the remaining ice at a much higher rate.

Just no. Ice sheet response tends to be parameterized, where a computationally simple approximation is used, including this.

IPCC doesn’t account for the aerosol cooling effect. If we cut our emissions there would likely be a rapid warming of 0.5-1.0°C within a couple of years as particulates in the air are blocking less sunlight.

This is complete nonsense. They've been accounting for it for ages. That's where figures like this come from.

The ice sheets don’t melt at a steady rate.

This is well known, and widely discussed.

Last time this much carbon dioxide was in the atmosphere they ended up retreating 600m per day which should affect predictions.

This appears to be from a single study of a particular set ice sheets off Norway which were grounded below sea level. Thwaites is like that, but much of the big ice sheets are not. Ice melt isn't some simple thing which will happen at the same rate everywhere.

Not strictly a feedback loop but worth mentioning… The earth contains less than 20% of the copper needed to produce the renewables required to replace fossil fuels over the next 20 years, about 20% of the required nickel and less than 2.5% of the required lithium.

This is a serious misreading of what's going on. There's enough in the earth's crust, but trying to depend only on existing mines would be a bottleneck. That's why a ton of new mines are opening.