What was done
The authors grew French bean (Phaseolus vulgaris cv. Groffy) in environmental cabinets at atmospheric CO2 concentrations ranging from 350 to 750 ppm in combination with air temperatures ranging from 14.5 to 18.5°C to study the effects of predicted climate change scenarios on yield production in this agricultural species commonly grown in the United Kingdom.

What was learned
Amazingly, elevated CO2 had essentially no impact on any plant variable.  However, increasing air temperature from 14.5 to 18.5°C boosted bean yield considerably.  In addition, the warmer temperatures increased bean quality and reduced the time to harvest by approximately 50%.  After deriving mathematical equations to describe the results of their study, the authors calculated that bean yields for this cultivar in the 2020s may be 39 to 84% greater than they are today, while yields in the 2050s may be 51 to 118% greater.

What it means
If air temperature in the United Kingdom increases in future years, regardless of the cause, it is likely that the yield and quality of French beans will be significantly improved, even without the aid of any concomitant rise in the air's CO2 content.