Recently the NY Times reported on the new IPCC report on agriculture. I have not read it, but am very familiar with the work of its lead author from Stanford University (David Lobell).

Above a critical temperature threshold, which for a number of crops is mid to upper 90s, pollen is damaged or rendered sterile, thus significantly depressing yields. Does pollen sterilized by extreme heat have an effect on bees? I have no idea. Maybe someone on this listserver knows. 

Previous IPCC reports have indicated that we can expect hotter average temperatures, longer periods of above average temperatures, hotter extremes, and for agriculture - longer growing seasons (with changes in planting dates, etc, which may then be out of sync with rains and hours of sunlight), as well as hotter temperatures at "inconvenient" times such as anthesis (flowering) as noted above. These conditions  - altering of seasonality and rain/temperature relationships - may even affect wild plant populations, and change species compositions and distributions. How will all of these changes affect bees? I am not sure anyone could know yet, but these are questions we might want to start considering.

While some may comfort themselves by saying that climate fluctuations are not unprecedented and species adapt (or don't), the pace and scale of change now is historically unprecedented. Furthermore, in agriculture, we are dealing with domesticated species meaning that their evolution is largely in our hands. Whether they successfully adapt has a lot to do with whether we help them to. So far, I am not convinced that society's efforts to help agriculture adapt are commensurate with the challenge.

Cary.

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