04/24/2013 05:25 pm ET | Updated Jun 24, 2013

Rethinking Agriculture: National Climate Assessment Provides (Another) Reason

It's Earth Week, a good time to celebrate the natural environment and also examine some of the ways we use -- and abuse -- Earth's resources and climate. Food systems are an important area for scrutiny. New agricultural ideas and actions are essential amid rising climate stress, a growing human population, widespread degradation of ecosystems, and rampant food insecurity; nearly one billion people regularly don't get enough to eat.

Pastoralists in Kenya, rice farmers in India, and industrial feedlot operators in the U.S. are contending with increased frequency of drought and erratic weather. But agriculture isn't just affected by climate change. It's also a significant source of greenhouse gas emissions (GHGs).

According to the U.S. Environmental Protection Agency (EPA), the U.S. agricultural sector was responsible in 2011 for 7.2 percent of U.S. GHGs. This doesn't include emissions from indirect agricultural activities, like clearing grasslands or forests to create farmland, or the fossil fuels burned when transporting agricultural products.

U.S. agriculture is heavily tilted toward large-scale, resource-intensive production of animals and the corn, soybeans, and hay (the U.S.'s three largest crops) that feed them. It might be hard to believe, but less than 2 percent of U.S. farm acres grow vegetables or pulses (beans and legumes) and less than 2 percent are planted with fruit or tree nuts.

The U.S. food system is also vulnerable to the effects of climate change. The draft National Climate Assessment, prepared by more than 200 scientists for the U.S. government and recently released for public comment, says this: "Production of all commodities will be vulnerable to direct impacts from changing climate conditions on crop and livestock development and yield."

And, it adds, "Climate change effects on agriculture will have consequences for food security both in the U.S. and globally. . . ." We've already seen this. When food prices rose because of the massive U.S. drought last year, increases weren't just seen domestically. Prices went up around the world. The most negative consequences -- putting some staple foods out of reach -- were felt in the poorer countries of the global South.

A re-visioning of U.S. agriculture could have vast global impacts. How the U.S. eats and produces its food has an enormous influence on other societies. In countries such as China, meat used to be a condiment or side dish. However, the Chinese increasingly are adopting U.S.-style (and U.S.-size) diets and methods of production, like factory farms, and searching for new sources of animal feed.

In the U.S. alone, nearly 10 billion land animals are consumed each year. Globally, it's well over 60 billion, and could double by 2050. Meat and dairy production already use 30 percent of Earth's land surface, 70 percent of agricultural land, and accounts for eight percent of the water humans use, mostly to irrigate feed crops. The global livestock industry is also, according to the Food and Agriculture Organization (FAO) of the United Nations "probably the largest sectoral source of water pollution," and one of the key agents of deforestation.

Animal agriculture is also a major contributor to climate change. The FAO estimates that 18 percent of global GHGs can be attributed to the world's livestock sector. Current and former World Bank environmental specialists concluded that a more accurate accounting is 51 percent.

Increasing demand for grain and oil-meals to sustain the growing livestock population also means that more of the planet's surface will have to be converted to cropland to grow food for farmed animals, not people. (About 98 percent of soy meal, created by crushing soybeans, is used as feed.)

Notably, these kinds of "indirect" factors were not included in the EPA's accounting of U.S. agricultural GHGs. Nor were the ways agriculture contributes to global climate change covered in the National Climate Assessment report -- a rather puzzling omission.

Other blind spots exist. The U.S. Department of Agriculture (USDA) organized a panel on the 2012 U.S. drought at last year's "COP18" climate summit in Qatar. When I asked the presenters whether the drought hadn't provided a strong rationale for reorienting U.S. agriculture to be more sustainable and climate-compatible, it was as if I was speaking Esperanto.

Nonetheless, the facts urge a course correction. The National Climate Assessment is straightforward: "Climate change poses a major challenge to U.S. agriculture, because of the critical dependence of the agricultural system on climate and because of the complex role agriculture plays in rural and national social and economic systems."

The U.S. has a real opportunity, and a responsibility, to cultivate a global shift away from its meat- and feed-heavy model of industrial agriculture and toward a more sustainable, equitable, and healthier food system. We're going to need public education, advocacy, technology, science, and individual action. The climate reality is that there's little time and even fewer resources to waste.

With thanks to Whitney Hoot, consultant to Brighter Green, for her assistance.