[flash_zombie]

> The issue is the rate of change, which is unprecedented.

Perhaps over some arbitrary timeframes within the measured record. On the other hand, a volcanic eruption can immediately cause a change of 1K or more.

But let's say it is unprecedented, so what?

> The path we're currently on will devastate ecosystems and cause a huge drop in crop production.

[citation needed]

This has been predicted numerous times, it didn't come to pass. Crop production depends on the weather far more than the climate, we have to deal with that issue anyway. So let's deal with the actual issue, not part of what may cause the issue, some of the time.

As for ecosystems getting "devastated" - so what? They get devastated one way or another all the time. They recover.

[eesmith]

Are you quibbling about what "huge drop" means?

Here's a citation - https://www.pnas.org/content/114/35/9326 "Temperature increase reduces global yields of major crops in four independent estimates".

> Without CO2 fertilization, effective adaptation, and genetic improvement, each degree-Celsius increase in global mean temperature would, on average, reduce global yields of wheat by 6.0%, rice by 3.2%, maize by 7.4%, and soybean by 3.1%.

When you write "This has been predicted numerous times", do you mean, for example, the predicted famines of the mid-1900s, saved by the Green Revolution? Borlaug's Nobel Prize speech cautious us technical success in raising food production is only a temporary victory - we must also limit our population.

When you write "Crop production depends on the weather far more than the climate" ... how is that even a valid argument? Where are the Canadian orange groves? How's the Brazilian maple syrup industry? They don't exist, because the climate is wrong for those crops in those areas.

You write "They recover" .. Citation needed. Simple counter-example - the Icelandic forests from the Norse era have not recovered.

Or, 10,000 years ago the Sahara was green. Now it's a desert. Why hasn't that ecosystem recovered?

[flash_zombie]

> Are you quibbling about what "huge drop" means?

No, I'm sincerely interested.

> Without CO2 fertilization, effective adaptation, and genetic improvement, each degree-Celsius increase in global mean temperature would, on average, reduce global yields of wheat by 6.0%, rice by 3.2%, maize by 7.4%, and soybean by 3.1%.

"Without adaptation" is not a plausible scenario. Of course there will be adaptation. But let's take those numbers anyway, and take a very liberal estimate of six degrees of temperature increase: That's 36% (wheat), 19.2% (rice), 44% (maize) and 18.6% (soy), respectively.

That may sound alarming if all that produce had to be turned into food that people need to live. In practice, most of it goes to livestock or even biofuel production. Being forced to have less cattle and fuel might be good for the climate, no?

> Borlaug's Nobel Prize speech cautious us technical success in raising food production is only a temporary victory - we must also limit our population.

Perhaps, but the best way to limit your population growth is to deliver a better standard of living.

> When you write "Crop production depends on the weather far more than the climate" ... how is that even a valid argument? Where are the Canadian orange groves? How's the Brazilian maple syrup industry? They don't exist, because the climate is wrong for those crops in those areas.

I'm talking about actual crop production, not hypothetical crop production. Nobody is starving because farmlands that never existed stop producing. With bad weather, that's different.

If we're talking about climate and agriculture, the argument goes both ways: If global temperature rises, then new places will start making sense for certain forms of agriculture, just as old places will stop making sense. This also will happen regardless of human intervention.

[nec4b]

And Antarctica had tropical climate once and now it's and ice desert. Things move slowly on geological scale, 10,000 years is a blip.