I’ve often viewed agriculture, urban agriculture in particular, from a resource perspective. In order to grow food, people need access to land, water, genetic stock and knowledge. I’ve taken for granted one absolutely essential resource: energy from the sun. This is available to everyone, everywhere, right? (Of course, I’m ignoring the far north and far south polar regions, that lose sunshine for months at a time.) Turns out I am wrong. I need to include access to sunshine as one of the critical factors.

In today’s New York Times, an article on air pollution describes a recent United Nations report that summarizes the severely diminished levels of sunshine available in much of Asia. The cause is pollution, plain and simple, pollution from cars, coal-fired power plants and slash-and-burn agriculture. Sunlight is reportedly reduced 10-25% at street level. While not threatening urban agriculture completely, the article cites Prof. Ramanathan, of the University of California, San Diego, who says research suggests rice harvest growth rates have been reduced by as much as 5% since 1960 in much of Asia. So, pollution is taking its toll. This is a problem that developing countries need to address. Not only does the pollution have severe direct impacts on individual health, but it also affects people indirectly by reducing food production.

Added comment, 5/15/09:

Another issue regarding sunlight arises for urban farmers and gardeners: shade. Because urban farming is often done around buildings and landscape trees, adequate access to sunlight is an important issue. There are limits to what you can do to deal with this problem. Rooftop gardening, taking down taller trees, using reflective surfaces to “move” or strengthen sunlight are all techniques one can use. But, the simplest thing one can do is find land that has good exposure to sunlight. This may mean putting your garden in your front yard, if that has a better exposure, or using a neighbor’s yard or using a plot in a community garden. Long term planning helps, too. If you’re looking for a place to live, one of your criteria for buying or renting should be a good exposure to sunlight.

Advertisements