Yeah, between the two papers, the Chatham house paper (and the PNAS paper it linked to, which Lynas also referred to in his interview) seemed like it provided a more plausible route to large scale disaster because it described the potential for sudden supply shocks (most plausibly 10-20% losses to the supply of staple crops, if we stay under 4 degrees of warming) that might only last a year or so but also arrive with under a year of warning.
The pessimist argument would be something like: due to the interacting risks and knock-on effects, even though there are mitigations that would deal easily with a supply shock on that scale, like just rapidly increasing irrigation, people won’t adopt them in time if the shock is sudden enough, so lots of regions will have to deal with shortfalls way bigger than 10-20% and have large scale hunger.
This particular paper has been cited several times by different climate pessimists (particularly ones who are most concerned about knock-on effects of small amounts of warming), so I figured it was worth a closer look. To try and get a sense of what a sudden 10-20% yield loss actually looks like, the paper notes ‘climate-induced yield losses of >10% only occur every 15 to 100 y (Table 1). Climate-induced yield losses of >20% are virtually unseen’.
The argument would then have to be ‘Yes the sudden food supply shocks of 10-20% that happened in the 20th century didn’t cause anything close to a GCR, but maybe if we have to deal with one or two each decade, or we hit one at the unprecedented >20% level the systemic shock becomes too big’. Which, again, is basically impossible to judge as an argument.
Also, the report finishes by seemingly agreeing with your perspective on what these risks actually consist of (i.e. just price rises and concerning effects on poorer countries): Our results portend rising instability in global grain trade and international grain prices, affecting especially the ∼800 million people living in extreme poverty who are most vulnerable to food price spikes. They also underscore the urgency of investments in breeding for heat tolerance.
Update: looks like we are getting a test run of sudden loss of supply of a single crop. The Russia-Ukraine war has led to a 33% drop in the global supply of wheat:
Yeah, between the two papers, the Chatham house paper (and the PNAS paper it linked to, which Lynas also referred to in his interview) seemed like it provided a more plausible route to large scale disaster because it described the potential for sudden supply shocks (most plausibly 10-20% losses to the supply of staple crops, if we stay under 4 degrees of warming) that might only last a year or so but also arrive with under a year of warning.
The pessimist argument would be something like: due to the interacting risks and knock-on effects, even though there are mitigations that would deal easily with a supply shock on that scale, like just rapidly increasing irrigation, people won’t adopt them in time if the shock is sudden enough, so lots of regions will have to deal with shortfalls way bigger than 10-20% and have large scale hunger.
This particular paper has been cited several times by different climate pessimists (particularly ones who are most concerned about knock-on effects of small amounts of warming), so I figured it was worth a closer look. To try and get a sense of what a sudden 10-20% yield loss actually looks like, the paper notes ‘climate-induced yield losses of >10% only occur every 15 to 100 y (Table 1). Climate-induced yield losses of >20% are virtually unseen’.
The argument would then have to be ‘Yes the sudden food supply shocks of 10-20% that happened in the 20th century didn’t cause anything close to a GCR, but maybe if we have to deal with one or two each decade, or we hit one at the unprecedented >20% level the systemic shock becomes too big’. Which, again, is basically impossible to judge as an argument.
Also, the report finishes by seemingly agreeing with your perspective on what these risks actually consist of (i.e. just price rises and concerning effects on poorer countries): Our results portend rising instability in global grain trade and international grain prices, affecting especially the ∼800 million people living in extreme poverty who are most vulnerable to food price spikes. They also underscore the urgency of investments in breeding for heat tolerance.
Update: looks like we are getting a test run of sudden loss of supply of a single crop. The Russia-Ukraine war has led to a 33% drop in the global supply of wheat:
https://www.economist.com/finance-and-economics/2022/03/12/war-in-ukraine-will-cripple-global-food-markets