The unlikely Earth Day hero.

• Position: Agriculture

Rising temperatures, erratic weather, population growth, and scarce water resources--along with growing civil unrest and skyrocketing food prices--are putting unprecedented stress on people and the planet. For more than 40 years, Earth Day has served as a call to action, mobilizing individuals and organizations around the world to address these challenges. Worldwatch Institute's Nourishing the Planet project highlights agriculture--often blamed as a driver of environmental problems--as an emerging solution.

Agriculture is a source of food and income for the world's poor and a primary engine for economic growth. It also offers untapped potential for mitigating climate change, protecting biodiversity, and lifting millions of people out of poverty.

Past attempts to combat hunger have tended to focus narrowly on a few types of crops, relied heavily on chemical fertilizers, and ignored female farmers. "There's been relatively little focus on low-cost ways to boost soil fertility and make better use of scarce water, and on solutions that exist beyond the farm and all along the food chain," stresses Christopher Flavin.

From urban farming projects that are feeding our growing cities to rotational farming practices that store carbon in the soils and help mitigate climate change, small-scale and low-input innovations can go a long way in protecting the environment--not only on Earth Day, but every day.

Nourishing the Planet offers a number of solutions to guide farmers, scientists, politicians, agribusinesses, and aid agencies as they commit to promoting a healthier environment and a more food-secure future:

Guaranteeing the right to food. Governments have a role in providing the public goods to support sustainable agriculture, including extension services, farmer-to-farmer transmission of knowledge, storage facilities, and infrastructure that links farmers to consumers.

Harnessing the nutritional and economic potential of vegetables. Micronutrient deficiencies--including lack of vitamin A, iodine, and iron--affect 1,000,000,000 people worldwide.

Reducing food waste. Increasing global food production is emphasized by "experts," yet our money could be better spent on reducing food waste and post-harvest losses.

Feeding cities. The United Nations estimates that 70% of the world's people will live in cities by 2050.

Getting more crop per drop. Many small farmers lack access to a reliable source of water, and supplies are drying up as extraction exceeds...