Every now and again one reads a paper saying something along the lines of "ZOMG we're all going to die of starvation". Perhaps not literally that, but it will say something like crop yields decline under global warming. And totally fail to mention that other factors - better farming, fertilisers, and so on - are increasing yields faster. So this is just a page for me to tag with the obvious rebuttals, and link to some of my old posts. My pic is from ourworldindata.org/grapher/cereal-production.Searching, I find Crop yields have increased dramatically in recent decades, but crops like maize would have improved more without climate change, but that too is from Our World in Data, rather than the breathless academic press.
* How overfed are we? [2008]
* How overfed are we? (part 2) [2009]
6 comments:
IIRC the price of higher yields is increased fossil fuel use in machinery and the Haber process. There is also the consequent increase in CO2 emissions
Are the increased yields sustainable in a world trying to reduce emissions?
There is also the potential ropadope in the 2070s as we simultaneously hit maximum population, severe climate change and the fossil fuels running out.
I believe the spelling is rope-a-dope. And although I don't know what severe climate change will do, my big worry is the world's fuel portfolio. I spent a couple of years writing a blog (3000 Quads) harping relentlessly on that theme--the subhead was 'The World Will Consume 3000 Quads in 2075. If They All Come From Coal, We're Screwed.' I haven't checked lately to see if we're still on track to achieve that dubious goal, but last time I looked, I found (and wrote)... : The US Department of Energy estimated in 2010 that the world would consume about 800 quadrillion BTUs in 2040. My calculations showed a figure of about 965 Quads. My fear was (and still is) that we would not be preparing for a world with much higher fuel use and that would lead us by default into using dirtier fuels, as they are easier to extract and get ready for use. (Turns out that I was pretty close to right–the Department of Energy just updated their forecast for 2040 to 940 Quads.)"
So if much of our energy needs are met by coal in 2075.... we're screwed.
More to the point of your post, last time I looked our farmers already produced enough food to feed estimated peak population. We just have to quit feeding so many rats with it, letting it spoil in unrefrigerated trucks or just plain throwing it away because of artificial expiration dates.
"In the United States, over one-third of all available food goes uneaten through loss or waste." https://www.usda.gov/about-food/food-safety/food-loss-and-waste
Yes, a lot of the increased yield is artificial fertilisers. And currently most of those are produced with fossil fuels. But I see no particular reason why that should continue; renewabales can substitute; all the process needs is energy.
Not quite. The Haber process uses methane as energy source and hydrogen source. The hydrogen is then used to fix nitrogen as make ammonia and the ammonia then makes ammonium nitrate fertiliser.
I suppose you could get the hydrogen from electrolysis, but you have to generate enough heat and pressure to make the ammonia.
IIRC 4% of our total energy budget is used to make fertilizer. I do not see any way around that.
Post a Comment