So then, the costs of fossil fuel emissions -- evaluated purely in terms of these results -- are less than their benefit? (That is, fossil fuel usage increased

So then, the costs of fossil fuel emissions -- evaluated purely in terms of these results -- are less than their benefit? (That is, fossil fuel usage increased agricultural productivity, while warming decreased it by a smaller amount.) Obviously, you wouldn't want to dismiss the concerns of GW on that basis, but this doesn't seem like a good reason to think GW is a problem, even as there are other good reasons.