I'll make a stab :
CO2 is considered fertilizer to plants.
Increased CO2 will increase crop yields,however CO2 does not discriminate between plants,and while crops grow,so do weeds.And more herbicides($) may be required per acre to control unwanted weeds,and the increased chemicals may exceed established thresholds for exposure.
Temperature is another animal.
Rice yield declines from higher night time temps.
El Salvador has lost 90% of its coffee crop due to elevated temps,along with 2,500 dead cane cutters over the last two decades,who experienced renal failure on the job,unable to remain hydrated in the increased heat.
In 2002 Canada saw a 5% drop in their wheat harvest due to temps.
In 2003 record heat in Europe cut production 90-million tonnes,and killed 52,000 people,in 9-countries.
In 2005 the U.S.Corn Belt saw a shortfall of 34-million tons.
In 2010 Russia lost 40% of it's wheat,leading to banned exports,food prices soared, which sparked the Arab Spring.56,000 people died in the heat wave,smog,and wildfires.
Pine beetle northern migration meant tree kills leading to lightning-triggered wildfires in the U.S..
