I guess I need to justify the ZOMG version. For example Climate change will cut crop yields; August 15, 2017 at phys.org: "Climate change will have a negative effect on key crops such as wheat, rice, and maize, according to a major scientific report out Tuesday that reviewed 70 prior studies on global warming and agriculture... the overall trend planet-wide is downward, signaling that steps are needed to adapt to the warming climate and feed an ever-expanding world population". Or the overall global effect of climate change has been small so far: losses of a few percentage points for wheat and corn from what they would have been without climate change. The overall impact on production of rice and soybeans was negligible, with gains in some regions entirely offsetting losses in others... But... temperature increases were expected to accelerate in coming decades, making it likely that the challenges to food production will grow in an era when demand is expected to rise sharply from the NYT in 2011. Or there's some weak stuff from RC in 2014; Eli covered the same thing.
The mistake these are making, and this is DA's point, is to look at crop yield with respect to GW in isolation, and miss all the rest that is going on: the many generic improvements in agriculture and related processing that our modern mechanised industrialised farming provides. Because what you actually care about is the overall crop yield, not the changes in yield broken down into many factors.
Wiki doesn't do a desperately good job either, in the text, making exactly the same mistake. But it does have the great virtue of including a graph, which I've inlined, so you can see for yourself that whatever may be going on in the detail, world food production is heading up. National Geographic does fairly well.
My point, of course, is that I've said all this before, so why did DA need to write his post? Except now I come to look, while I'm sure I've thought all this before, I don't find myself making the point explicitly. I've got close. In 2009, I ask Could Food Shortages Bring Down Civilization? and predicatably answer "no". In 2008 I wondered How overfed are we? and the answer is there is spare in the system. Infertile Crescent?, from 2016, looks at GW and war and concludes that crap govt is the main problem. Climate inaction to be ‘catastrophe’, from 2014, is again skeptical about the crop yield problem, but without making the key point.
The good reason why you'd want to look at changes in yield broken into changes from different components is that it might help predict the future: if you could show that changes due to GW were small now, but could reasonably be expected to increase, and in 50 years overwhelm the changes due to tech, then that would be useful. But none of the ZOMG studies even try to do that, as far as my admittedly small survey shows.
1. Temperature increase reduces global yields of major crops in four independent estimates, Chuang Zhao, PNAS, DOI: 10.1073/pnas.1701762114.