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Comment by romaaeterna | Hacker News Reader

There is also 15% more green vegetation on the planet right now than a few decades ago, due to recent warming, much in formerly marginal areas. Some millions of people potentially dead from famine are likely still alive thinks to the extra food resources. (Along with quite a number of assorted non-human critters supported by it all.)

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An uptick in crop failures due to irregular growing seasons has lead to things like the Syrian civil war, which is a fairly direct cause of the immigrant crisis in Europe which is a fairly direct cause of the rise of ethno nationalism in Europe.

This paper disputes your claims about the effects of climate change on Syria’s current state: https://www.sciencedirect.com/science/article/pii/S096262981...

Just because there is more vegetation over all does not mean that food crops produce higher yields. Climate change decreases yields by creating more extreme patterns in precipitation and temperature fluctuation.

If "extreme patterns in precipitation and temperature fluctuation" are doing that, you should see decreased greening in the satellite data. But we haven't.

https://www.nature.com/articles/nclimate3004

According to the above (2016) Nature article, 25% to 50% of the globe shows greening, with only 4% showing browning.

Lower yielding crops are still green, color has nothing to do with the weight produced per plant. Yield is related to physiological stress on the crop: over water a plant it stays green while the roots rot, put it in drought conditions or heat it up for slightly longer and it gets stressed; either way you're reducing the harvest yield.

Additionally if the greening is occurring in previously permafrost soils that are not very useful for farming then there is not an increase in the food produced by that green area.

World crop yields are up year on year, according to the USDA. See Table 01 World Crop Production Summary here:

https://apps.fas.usda.gov/psdonline/circulars/production.pdf

Interesting, although year to year is a bit of a small scale to compare. Also the first sentence mentions a drought that dropped 5% of Russian wheat from the previous month, but that left the yield 4% higher than the previous year. It's possible that the increases from higher temps offset the longer droughts in some cases. If variance in rain and temperature continue to increase there will eventually be a tipping point where yields are severely reduced.

Well sure, there must be a tipping point somewhere, but the earth has been a lot hotter in the past than it is now, and biomass was in much greater quantity at such times.

It's glacial maximums that are really concerning to me personally. It's very unlikely that we could feed so many billions of people as we do now if we ever enter another ice age.

Do you have any references to back up these claims, especially the assertion concerning famine?

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