What about that expanded harvest?

So, to recap, deniers first said there was no global warming. Then, they said any warming was so small that we didn't need to worry about it. Then, they said it was all just a natural cycle. Now, they are saying it is actually good for us. Do you see a trend here?

One of the things they are now claiming is that global warming will increase the zone where we can grow crops and increase the length of the growing season. In this way, it is actually  good for us. So, how is this turning out?

I have always been very skeptical of this claim, mainly because I grew up in agricultural areas and have always followed agriculture. I do some work in the local vineyards with some friends in this area. Growing a crop is about a lot more than planting seeds and then kicking back until harvest time. You have to worry about weeds, disease, insects, watering and weather - just to name a few things.

Droughts and heat waves have a devastating effect on crops. Just take a look at what is happening to the farms in California right now. They are having to plow their crops under because they don't have enough water. On the other hand, too much water can be just as bad. A flooding rain can wash a whole farm out in a matter of a few hours. The evidence shows that overall, droughts and floods have been about the same so far, but dry areas are getting drier and wet areas are getting wetter. So, areas with droughts are getting worse and areas with floods are also getting worse.

Another weather event that farmers fear is the hail storm. A severe hail storm can pound a crop into the dirt in just minutes.

Of course, the obvious point is it doesn't matter how long the growing season is if you don't have a crop.

And, a warmer climate will also result in better conditions for insects and diseases that destroy crops.

None of this takes into account the fact that grain crops such as corn and wheat are very sensitive to heat. The yield goes down once the temperature gets higher than a certain point.

I had all of this in mind when I read an article in the May 13 issue of Eos, Transactions, American Geophysical Union.  Climate change, water rights, and agriculture: A case study in Idaho reports on an investigation into the effects of climate change on agriculture. Their findings?

"They found that if climate change increases the volatility of the temperature and the water supply, irrigated agriculture in the region could face significant damages. In fact, crop revenue losses could be up to 32%."

This is just one study for one particular region, but the point is pretty clear. Just because more land is available for growing crops and the length of the growing season is longer, it doesn't mean there will be a larger harvest. Climate change will make certain things better for crops, but it will also make a lot of things worse at the same time.

Again, we see that all of us at the bottom will have to foot the bill for all of this. This time, in the form of higher food prices.