Do your beans grow tall?

Being here in Cancun in the middle of the UN talks it is easy to start to become obsessed with the minutiae of the negotiations themselves and lose sight of what is at stake. The UN actually does a pretty good job of outlining in some of their documents many of the social impacts that environmental changes from shifting climates are likely to have in locations around the world. Perhaps it is a good idea at this point to take a step backwards and look at what is at stake from the human perspective. Especially as any adaptation measures will be designed to adapt to the set of impacts identified here.



Agriculture: While Mark talked about the impacts of agriculture in an earlier post allow me to reiterate some related points.  It's worth revisiting as we all have to eat no matter how rich or poor we are. The clearest impact of agricultural production in the face of climate changes is the availability of water. One way to assess this is by looking at precipitation, another is to look at soil moisture - the water available in the subsurface for plant growth. Without precipitation or available soil moisture during the growing season, any discussion of agriculture becomes academic.

Largely an unknown in most of the General Circulation Models is what is going to happen to the frequency and magnitude of extreme weather events. Extreme events can be even more complicated to understand than long-term average conditions because you cannot generalize as much.

If we go back to the baseball analogy we used previously to describe distinctions between weather and climate, forecasting extreme events is akin to being able to predict a hitters hot streaks or cold slumps. While it might be safe to say that Albert Pujols will most likely hit for a .331 batting average in a given year, it's much more difficult to know if he will do so by sustaining a steady pace or through wild swings of hot streaks and slumps. From a fan's perspective, a streaky player can be nerve-wracking. From an agricultural perspective, streaky weather events can be deadly for crops.

There are also less obvious problems associated with farming in a shifting climate as well. Reducing the amount of water available to grow crops will increase the stress on existing resources and stress on the crops themselves. Water will be used and re-used. While recycling is generally a good thing, this can also lead to issues of compromised soil fertility, salinization, and reduced water quality.

While this is bad enough for crop production and human use, if any of this degraded water is critical to downstream ecosystems, they will be negatively affected as well. When crops are stressed, they are more susceptible to pests and disease vectors. While it has always been a dangerous world for agricultural crops, the threats lurking behind the furrows are growing more forbidding. Be careful beans...