this post was submitted on 04 Jan 2024
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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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[–] rekabis@programming.dev 5 points 10 months ago* (last edited 10 months ago)

Plus, current climate change has seen a velocity across a mere century that prior events took tens of thousands of years to achieve.

This imparts an “inertia” to our current climate that - even if we stopped on a dime, right now - will lead to conditions that may have most of the planet outside of the polar regions as being uninhabitable year-round due to chaotic weather and lethally high wet bulb temperatures that AC is simply unable to handle.

And if we don’t stop; if we continue on our “business as usual” path for another 10 or 20 or 30 years, said inertia could conceivably push the entire planet over into a full-blown Venus Scenario, wiping all life from the face of the planet.

Warming trails CO2 by 15-20 years. We are now seeing the 1.5℃ of warming of 2003, when Windows XP was released. If we hit CO2 levels that predict 5℃ of warming, humanity has essentially dug its own grave, the planet will (once warming catches up) no longer have any carrying capacity for us to survive in sufficient numbers. If we hit CO2 levels that predict 8-10℃, we run a non-trivial possibility of a tip-over into a Venus Scenario.

Prior events took many tens to hundreds of thousands of years, allowing entire ecosystems to migrate to and from the poles. This allowed the biosphere to “put the brakes on” warming itself because they never stopped being robust sequesters of CO2.

We don’t have that in play, here. Entire ecosystems will die in-place because they simply don’t have the time to migrate. We will see extinctions on a scale never before seen in the geological record. And the very robust biosphere that saved the planet in prior warming events will be commensurately weakened in this one, likely to the point where it cannot effectively sequester sufficient CO2 to stop the warming.

TL;DR: as a species, the likelihood that we are all endlings is uncomfortably high. Humanity may not see the year 2100, and will most likely not see the year 2200.