Things are getting better part 2

[GregLocock]

Estimates of crop yields in USA out to 5 deg C of warming.

https://www.nature.com/articles/s41598-025-90254-2

 

[TugboatEng]

Meta-analysis, ugh. Let's take the same bad data from before and try to come up with better results.

 

[GregLocock]

Shrugs, the author is the guy who proved that Mann's hockey stick analysis was bad maths (and rotten science but that's a separate issue). If anyone is going to do meta analysis i'd rather it was him.

 

[dik]

Things may be getting worse in other areas. Winnipeg is likely to improve. We used to have a week or so of -35C to -40C weather in January and February. For the last 20 years it's hardly gotten below -30C.

 

[btrueblood]

I like how he pointed out the C14 curve was forced to be nonlinear, affecting marginal yields, versus just fitting the data as he did.

 

[JoshPlumSE]

Dik: Things may be getting worse in other areas. Winnipeg is likely to improve. We used to have a week or so of -35C to -40C weather in January and February. For the last 20 years it's hardly gotten below -30C.

The general hypothesis that warmer weather leads to better growing seasons for farmers is not very controversial. Now, that's assuming that you still have adequate water supplies, of course.

In general, it's drought and colder weather that hurts food production. Unless droughts greatly increase due to global warming (a dubious hypothesis), the net effect (at least in terms of food supply) will almost certainly be beneficial.

 

[GregLocock]

"Under elevated CO2 concentrations, plants use less water during photosynthesis. Plants have openings called stomata that allow CO2 to be absorbed and moisture to be released into the atmosphere. When CO2 levels rise, plants can maintain a high rate of photosynthesis and partially close their stomata, which can decrease a plant’s water loss between 5 and 20 percent. "

How Climate Change Will Affect Plants

While elevated levels of CO2 can help plants grow, the impacts of climate change mean it’s not all good news for the plant world.

news.climate.columbia.edu

 

[dik]

In general, it's drought and colder weather that hurts food production.

Yup... but if you're not a plant, -30C is better than -40C.

 

[JoshPlumSE]

Dik -

Correct me if I'm wrong. But, weren't we talking about crop yields and food supply?

Honestly, even if we were talking about the massive levels of warming like you suggest (which I don't think is very realistic). Don't we know (or strongly suspect that the Arctic and Antarctic are where the largest warming is expected to occur due to CO2 emissions? Whereas the equator would see much less warming. This would mean that it would only make the world BETTER suited for human habitation.

 

[dik]

Correct me if I'm wrong. But, weren't we talking about crop yields and food supply?

I suspect with climate change, the crop yields in Manitoba will slowly improve, caused by the change in temperatures. On the downside, things will likely change for the worse in other areas of the world.

 

[GregLocock]

Oh the Arctic is getting warmer. The Antarctic is getting colder. In between is in between.The theory that can explain everything has been used to 'explain' why GW was to blame for extended sea ice in Antarctica in 2014, and is also to blame for reduced sea ice in the Antarctic now (even though it is colder). Shock horror it may be that variability is a thing and that GW is not the control knob.

Here's a rather tricky graph. They've used the temperature of the tropics as a baseline, and then subtracted the temperature of the Arctic and Antarctic from that. So Antarctica is getting cooler relative to the tropics, and the Arctic is getting warmer. I strongly suggest you read all the bits of text.

 

[dik]

Oh the Arctic is getting warmer.

...four times faster than the rest of the world.

 

[GregLocock]

And Antarctica is getting colder. The World is a Very Big Place and there is region to region variation. I'm surprised you didn't know that.

 

[dik]

I did, but it's just not relevant other than how it affects climate change.

and in other places:

Global glacier melt is accelerating, new study finds

A new study published in Nature finds ice is melting at a ‘concerning’ rate, with repercussions for sea-level rise.

www.aljazeera.com

 

[SnTMan]

It is well known that everyplace is warming faster than every other place.

LOL

 

[GregLocock]

I'll assume dik's study is this one

"
The research shows the world's glaciers collectively lost 6.542tn tonnes of ice between 2000 and 2023, causing an 18mm (0.7in) rise in global sea levels. The world's glaciers lost an average of 273bn tonnes of ice every year -- the equivalent of 30 years of water consumption by the entire global population.

The assessment, led by scientists from the University of Edinburgh and the University of Zurich, found that so far this century, glaciers have lost approximately 5% of their total volume. Regional losses were highly variable; the Antarctic and subantarctic islands lost 2% of their volume but central Europe's glaciers lost 39%.

"These numbers are staggering. They serve as a reminder that things are changing fast in some regions," said Prof Noel Gourmelen, the co-lead author of the study and personal chair of Earth observation at the University of Edinburgh's school of geosciences. A stark contrast in the amount of ice lost each decade was also discovered, with 36% more ice having melted between 2012 and 2023 compared with the previous decade."

so 5% of their volume is 18mm, therefore high school maths tells us that if every glacier completely melted, you'd get a bit over 1 foot of sea level rise. I don't know about you, but our typical interdaily tidal range is approximately 6 feet. So a 1 foot shift in that doesn't sound much. That is of course assuming the numbers in the summary are correct.