win96

Interesting, although year to year is a bit of a small scale to compare. Also the first sentence mentions a drought that dropped 5% of Russian wheat from the previous month, but that left the yield 4% higher than the previous year. It's possible that the increases from higher temps offset the longer droughts in some cases. If variance in rain and temperature continue to increase there will eventually be a tipping point where yields are severely reduced.

Lower yielding crops are still green, color has nothing to do with the weight produced per plant. Yield is related to physiological stress on the crop: over water a plant it stays green while the roots rot, put it in drought conditions or heat it up for slightly longer and it gets stressed; either way you're reducing the harvest yield.

Additionally if the greening is occurring in previously permafrost soils that are not very useful for farming then there is not an increase in the food produced by that green area.

Just because there is more vegetation over all does not mean that food crops produce higher yields. Climate change decreases yields by creating more extreme patterns in precipitation and temperature fluctuation.