[duozerk]

At 4C of heating, you cannot grow food in any reasonable quantity with any reliability, period. 4C is the collapse of modern civilization at the very least (in fact likely earlier due to increased geopolitical instability and tensions due to dwindling resources, combined with the availability of nuclear weapons), with a massive die-off of humans along with it.

[trashtester]

Many places could increase food production to twice what it is today if 5C warmer.

[duozerk]

We're at +1.5C, more or less, and growing the usual grapes in France - of all places - is already becoming much harder (they keep dying of frost after waking up due to wild temperature swings).

At +5C, there is no growing food in any substantial amount outside of high tech, low yield approaches; approaches that depend on complex planetary supply chains (both for initial deployment and maintenance), which will have disappeared by then.

[trashtester]

> At +5C, there is no growing food in any substantial amount outside of high tech,

It seems you have some specific geographic region in mind. Earth has a lot of regions that are more than 5C colder than the most fertile regions.

People adapt. People move. Sometimes they fight wars about it. This has happened many times before.

We're currently living it the most peaceful, prosperous and safest period that humanity has ever experienced. (Despite what social media is tricking our brains into believing). In the future we will surely live through periods that are closer to the average. But I'm not seeing any extinction-level events due to climate change within the next few hundred years.

AGI or nukes, on the other hand, they both DO have the potential to end us as a species.

[saagarjha]

You seem to think that a couple of degrees just applies uniformly across the planet, or to a specific location, transforming somewhere cold into something which is now suddenly hospitable. That isn't how climate change works. It doesn't mean that Canada will suddenly be nice and balmy year-round; it means that the climate will fluctuate more wildly and wreak havoc on our agriculture, as described in the comment above. The temperature change is a global average, and your local experience is going to be a lot worse at the extremes.

[trashtester]

> You seem to think that a couple of degrees just applies uniformly across the planet

I don't believe that at all. I even studied the IPCC for how their various scenarios lead to different levels of increased heat in different places.

When it comes to fluctuations, there are several types. An obvious one is wind, which will probably become noticeably more chaotic with more energy. Another is temperature.

Temperature variations generally depend on humidity and wind. As winds get stronger, that in isolation leads to some increase in temperature variations.

For humidity (both at ground level and in the atmosphere), increased humidity leads to lower temperature variations.

There are also precipitation. Higher temperatures lead to heavier rain (when it rains), and can increase the likelihood of hailstorms.

There are also extreme weather patterns that become more common when it gets colder. While tropical storms and hurricanes increase in frequency in hot weather, more laminar storms ("winter gales") get more common when the weather is colder. I believe this is because the LACK of turbulence/chaos means there are fewer factors that can break up such storms.

This last type is common in places like Canada, Scandinavia or Siberia now, and come almost exclusively during winter.

Btw, the impact of increased temperature on weather is something that we can already observe on Earth today, simply by travelling between different weather zones. While SOME of the extra energy can affect areas far away from where the heating occurs, a lot of the effects are local or regional.

That means that it's likely that Temperate Zone type weather is going to shift a bit to the North, and include a greater proportion of Canada, Scandinavia and Russia. These areas will then get weather more similar to places like the US/German/China today.

The southern parts of the temperate zone is likely to see weather patterns that resemble tropical (or desert) weather zones. Much of the US can be more like Mexico, France can be more like Morocco or Greece, Sothern China more like Thailand, and so on.

This means that areas that get warmer AND dryer (like Spain, Italy and France, probably) will get some of the variations currently seen in Sahara.

But it doesn't mean that the temperature fluctuations get greater everywhere. Some areas become more humid, and that means lower fluctuations.

Btw, for humans, dryer weather can be an advantage, since it allows us to dissipate heat much more easily. For farming it's less ideal. Places like Saudi Arabia could go in the opposite direction, with higher humidity and more rain, farming could become easier, but the risk of wet bulbs could also go up.

Anyway, while it is true that more energy in the atmosphere ON average increases the frequency of most types of extreme weather, it is not true that it will increase all types of extreme weather everywhere.

EDIT: Here's a map: https://archive.ipcc.ch/publications_and_data/ar4/wg1/en/ch1...

[saagarjha]

Ok, but I fail to see why we would want to increase extreme weather on average? Like, if we happen to make some part of the planet a little better for agriculture by accident, while ruining the rest of it, how is that a good thing?

[mrguyorama]

"5C warmer" doesn't mean a uniform increase in temperature of 5 degrees at all times. It means "5 * the thermal mass of the earth's biosphere" worth of extra energy in an extremely chaotic system that is currently in a local stable point, but doesn't have to stay there.

[trashtester]

Just to clarify. The reason I didn't respond to this one:

> "5C warmer" doesn't mean a uniform increase in temperature of 5 degrees at all times.

Is because I thought it was completely obvious that this is correct. I've seen that several responses thought I ignored and argued that 5C warming would be the same everywhere, while what I meant by "5C warming" was "the effect of a global 5C warming".

What I DID think was the main message was this one:

> It means "5 * the thermal mass of the earth's biosphere" worth of extra energy in an extremely chaotic system that is currently in a local stable point, but doesn't have to stay there.

While I agree that a "5C global warming scenario" may mean that the average temperature in Lyon, and even that the VARIANCE of the temperature IN LYON may go up quite a lot, I did have objections with the hypothesis that the chaos would be the main factor leading to variations in temperature.

While, for the global average, increased energy in the atmosphere may lead to SOME increase in the variation in temperature, I don't think that variations in temperature depends nearly as much on the energy in the atmosphere as other types of extreme weather, such as hurricanes, heavy rain, hail storms etc. (And effects of those, such as destroyed crops, damage to property or flooding).

Changes in humidity seems to be a much greater factor in the variability of temperature than this extra energy has.

If you check the IPCC projections for changes in precipitation patters, maximum and minimum yearly temperatures, you will find that in areas where precipitation is expected to increase, the minimum yearly temperature goes up a LOT more than the maximum yearly temperature goes up, especially so in the sub-arctic part of Eurasia (like Siberia).

Meanwhile, in areas that are expected to get dryer (including Spain, France and Italy), the minimum yearly temperature hardly increases at all, while the maximum temperature goes up a lot more than the global average.

Basically this means that some vineyards in France, Italy and Spain may have to move to more robust crops, like maybe olives. But it also means that new areas open up that may become more favorable to vineyards, for instance in Germany, Poland or even southern Sweden.

[trashtester]

A 5C warming is indeed likely to make a few areas uninhabitable. I'm not saying climate change is not a problem. I'm just saying it's not an extinction event.

But keep in mind that the areas that tend to get the greatest warming tend to be the dry ones. In such places, sweating will still allow human bodies to regulate body heat, if air conditioning breaks down.

[mrexroad]

I think you missed the above comment’s point about risk to stability in a chaotic system…

[trashtester]

That part looked like gibberish.... Maybe rewrite to make it more clear?

[dTal]

From a different comment whose main thrust you also ignored (you are all over this thread with the same fallacy):

>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.

[mrexroad]

Stability in a chaotic system is precarious. Changes, even if small or seemingly trivial, can cause massive cascading effects from positive/negative feedback loops.

Sigh, I don’t mean to sound like a dick, but if that’s gibberish then you might want to strengthen some of the foundational understandings around systems.

[goatlover]

Source for these claims?