This is the tenth of a continuing series of essays and interviews from Earth Institute scientists on the prospects for a global climate-change treaty. Check with us daily for news and perspectives, and to make comments, as events unfold throughout the Copenhagen meetings.
Agronomist Pedro Sanchez has helped many regions of the world boost food production through better use of nutrients, and now heads the Earth Institute’s Tropical Agriculture and Rural Environment Program. He is at the Copenhagen summit looking for support to build a global soil map that will help farmers work more efficiently in the future. He spoke to journalist Kim Martineau about food, forests and climate change.
How will global warming affect food production in Africa?
We expect that a warmer climate will cause a stronger El Niño—the periodic warming of the east Pacific Ocean that changes global rainfall patterns. A stronger El Niño would bring more rain and flooding to regions in East Africa and longer dry spells to regions in sub-Saharan Africa.
How will farmers adapt to prolonged dry spells?
Improve crop yield. Increasing plant cover lowers the amount of water lost to evaporation. The plants form deeper roots and added leaf surface, allowing them to use water more efficiently. Africa currently grows one ton of cereals per hectare, versus nine tons in the U.S, but has the ability to triple its yield, through fertilizer, improved seed varieties and irrigation. It has already happened in Malawi.
What crops grow best in a drier climate?
Sorghum, cassava, millet. Corn is popular, but less suited to dry conditions.
How can farming in America become more sustainable?
Farmers in the U.S. tend to use too much nitrogen fertilizer, hoping that each year might bring a bumper crop that will boost their bottom line. The excess nitrates wash into streams and rivers, choking the ecosystem. We should also take a hard look at cattle feed lots. Cows were never meant to eat corn. We should go back to letting them forage on pasture grass, where their manure naturally returns nutrients to the soil instead of accumulating in mountains on feed lots. Grass-fed beef is also less fatty. I was just in Costa Rica and ate a delicious grass-fed steak.
So, you’re a carnivore?
Yes– I’m not advocating vegetarianism.
Is local food the way to go?
Surprisingly, no. Some areas of the country can produce food more efficiently than others. It would be very, very, hard in a temperate climate like New York to grow all the food we need and want. If people feel we should not eat tomatoes in winter, I respect that, but I like to eat tomatoes throughout the year because they are good for my health. What we can do is find better ways to ship the food, by train, for instance, rather than truck. Warren Buffet got it right. That guy is so sharp.
What should be included in any climate treaty?
Any climate deal should include incentives to keep tropical forests intact. Up to a quarter of global greenhouse gas emissions come from the logging and burning of forests. One proposal at Copenhagen would use a carbon-credit system to pay countries to keep their trees standing. Tropical forests are the greatest source of biodiversity we have left. Many of these species could be extremely useful to humans.