[duozerk]

Despite the IPCC being very conservative/optimistic in their scenarios, this is in fact in line with their reports; admittedly my comment above might be badly worded - when I said "near-term", I meant "in the upcoming two centuries or so".

The IPCC reports say we might reach 4C, 5C or even more; based on the historical record, such a major change in such a short time - several orders of magnitude faster than previous CO2e-gases-linked mass extinction events - likely cannot be adapted to by the majority of species (there will of course also be a few evolutionary winners), resulting in potential extinction. I also quote the latest draft report from that same IPCC, leaked about two years back by concerned involved scientists to newspapers before the usual step where political stakeholders are allowed to reword the parts they deem too disturbing or against their interests:

"Life on Earth can recover from a drastic climate shift by evolving into new species and creating new ecosystems," it says. "Humans cannot."

[baq]

The IPCC also consistently underestimated sulphur in the atmosphere because if you look at this and previous years we've reached their 2030-2035 goal of warming this year.

> GHG emissions will lead to increasing global warming in the near term, and it’s likely this will reach 1.5°C between 2030 and 2035.

https://climatechampions.unfccc.int/the-ipcc-just-published-...

> Global temperatures have been exceptionally high over the past three months – at around 1.6C above pre-industrial levels – following the peak of current El Niño event at the start of 2024.

> The past 10 months have all set new all-time monthly temperature records, though the margin by which new records have been set has fallen from around 0.3C last year to 0.1C over the first three months of 2024.

https://www.carbonbrief.org/state-of-the-climate-2024-off-to...

[trashtester]

There is lots of space on earth that would be a lot more hospitable to humans if 5C warmer. Like the central eurasian steppe.

[duozerk]

You can't grow food for a large population when average planetary temps are at +5C. It doesn't mean it's locally always +5C warmer than it used to be; it means you're seeing insane temperature swings in a matter of days, constantly - in both directions, it just so happens that the average is +5C.

Not to mention, at +5C it is all but certain shallow methane hydrate deposits (those stabilized by temperature, not pressure) all over the world are now outgassing CH4; not to mention several other similar tripwires, and likely not all of which we've even identified.

Edit: I can't seem to be able to reply to your comment below, not sure why. You're absolutely wrong about those Siberia figures, and they're not supported by current scientific consensus.

[trashtester]

If you farm a siberia that's 5 degrees warmer and more humid (also in ipcc data), you can maybe feed 10 billion just from there.

[baq]

average is an average, you're forgetting about extremes.

it only takes a few days (or hours) of above wet bulb temperatures to kill humans who live in and around the tropics today.

https://en.wikipedia.org/wiki/Wet-bulb_temperature

[trashtester]

So people will move out of those worst affected areas.

[baq]

Exactly. Hundreds of millions of them.

[trashtester]

Sure. That could happen. Or there could be wars/conflicts resulting in some of those not having anywhere to go.

Still, this scenario is quite different from human extinction, which is what I was responding to further up.

[triceratops]

What's the soil quality over there?

[duozerk]

Much of the soil in Russia that will warm is indeed acidic and largely inexploitable, which I suspect is what you were getting at; to their credit though, they picked an area that isn't (IIRC). Not that it changes much.

[trashtester]

Most soil can be used for some type of farming with some help from fertilizers. Temperature and access to water is more critical. Higher CO2 also increases crops, in isolation.

We're also talking about a time span of 100-300 years. Keep in mind how much more efficient farming is now compared to even the 1950's.