How Civilization is Going to EndJan 8th, 2009 | By Jonathan Golob | Category: Environmental
Wonder no more.
University of Washington climate scientist David Battisti looked at 23 of the best computational models of the climate available to predict the effect of climate change on global crop yields by the end of this century.
Our results show that it is highly likely (greater than 90% chance) that growing season temperatures by the end of the 21st century will exceed even the most extreme seasonal temperatures recorded from 1900 to 2006 for most of the tropics and subtropics. Presently there are more than 3 billion people living in the tropics and subtropics, many of whom live on under $2 per day and depend primarily on agriculture for their livelihoods (4). With growing season temperatures rising beyond historical bounds, the inevitable question arises: Will people in these regions have sufficient access to food to meet population- and income-driven growth in demand in the future, and thus to achieve food security?
So what? We’re (humanity) totally doomed.
Their conclusions with regard to agriculture are sobering. “In the past, heat waves, drought, and food shortages have hit particular regions,” says Battisti. But the future will be different: “Yields are going to be down every place.” Heat will be the main culprit. “If you look at extreme high temperatures so far observed–basically since agriculture started–the worst summers on record have been mostly because of heat,” not drought, he says.
The models predict that by 2090, the average summer temperature in France will be 3.7°C above the 20th century average. Elevated temperatures not only cause excess evaporation but also speed up plant growth with consequent reductions in crop yields, the authors note. Although rising temperatures may initially boost food production in temperate latitudes by prolonging the growing season, Battisti and Naylor say crops will eventually suffer unless growers develop heat-resistant versions that don’t need a lot of water. “You have to go back at least several million years before you find … temperatures” comparable to those being predicted, Battisti says.
Developing such crops, even with genetic engineering let alone just with ‘organic’ selective breeding, is far from certain. And then, there’s this:
A major lesson from this case and the recent food crisis is that regional disruptions can easily become global in character. Countries often respond to production and price volatility by restricting trade or pursuing large grain purchases in international markets—both of which can have destabilizing effects on world prices and global food security. In the future, heat stress on crops and livestock will occur in an environment of steadily rising demand for food and animal feed worldwide, making markets more vulnerable to sharp price swings. High and variable prices are most damaging to poor households that spend the majority of their incomes on staple foods
And remember, according to some of the best observations, climate change isn’t something we can prevent. Climate change already occurring.