Category Archives: Resource Constraints

Over the last few days, one of my favourite bloggers, Stuart Staniford of Early Warning, has done a couple of posts looking at the impact of climate change on food production. I generally agree with most of what Stuart writes, but on this occasion I have a number of major caveats. Indeed, I think his analysis paints a far too rosy picture of agricultural production in an era of climate change.

Before we start, we need to be a little careful about equating extreme weather with climate change. Given that we are in the foothills of global temperature rise, we can’t specifically assign particular events to climate change. The whole question needs to be looked at in probabilistic terms. Here is Bob Corell, Jeff Masters and Kevin Trenberth writing an opinion piece in Politico after Hurricane Sandy.

Overall, we know that climate change has stacked the deck so that this kind of event happens more frequently. That answer, however, prompts a deeper, more unsettling question that many want to know: is climate change worsening some recent extreme weather events like super storm Sandy? The short answer is yes. Climate scientists broadly agree that the extreme weather we’ve seen over the past few years is exactly what we’d expect to see in a changing climate.

So while we can’t definitely say that climate change is responsible for recent extreme weather events that have disrupted food production, we can say that climate change makes such events more likely and more extreme.

Nonetheless, for the sake of argument, let’s just hypothesise for a minute that recent extreme weather events such as the droughts in Australia, the U.S. and Russia are due to climate change. I will run with this assumption because Stuart appears to be claiming that regardless of how we categorise recent extreme weather events, they are not showing up in the agricultural production data—or, ultimately, in people’s stomachs.

In his first post on the subject, titled “Climate Change Still Not Affecting Global Cereal Yields“, Stuart reiterates a conclusion made two years previously:

So, clearly, the overwhelming story in global agricultural yields is this: improving agricultural technology has increased yields at a steady, reliable pace – they have more than doubled over the last 50 years. There just is absolutely no support in the data for the idea that climate change, or any other negative or scary factor you care to name – eroding soil, depleting aquifers, peaking oil supplies – is causing the agricultural yield curve to start bending downward. Maybe they will in the future, but it sure isn’t happening yet.

And he updates and republishes this chart to reinforce the point:

Which allows him to reach this conclusion which does not just cover yields but also overall production:

Climate change is scary, we are clearly melting the north pole, droughts and floods and heat waves are increasing over time. However, so far, it’s not hitting us where it would really hurt: in the stomach.

The chart looks like compelling evidence that climate change is not showing up in food production, but there are a number of problems. Continue reading →