Pesticide use has increased since 1950 to 25 million tons annually worldwide, yet crop loss from pests has remained relatively constant. The World Health Organization estimated in 1992 that 3 million pesticide poisonings occur annually, causing 220,000 deaths. Pesticides select for pesticide resistance in the pest population, leading to a condition termed the “pesticide treadmill” in which pest resistance warrants the development of a new pesticide.
An alternative argument is that the way to save the environment and prevent famine is by using pesticides and intensive high yield farming, a view exemplified by a quote heading from the Center for Global Food Issues website: “Growing more per acre leaves more land for nature”. However, critics argue that a tradeoff between the environment and a need for food is not inevitable, and that pesticides simply replace good agronomic practices such as crop rotation. You are what you eat!
Climate change has the potential to affect agriculture through changes in temperature, rainfall (timing and quantity), CO2, solar radiation and the interaction of these elements. Agriculture can both mitigate and/or worsen global warming. Some of the increase in CO2 in the atmosphere comes from the decomposition of organic matter in the soil, and much of the methane emitted into the atmosphere is caused by the decomposition of organic matter in wet soils such as rice paddies. Further, wet or anaerobic soils also lose nitrogen through denitrification, releasing the green house gases nitric oxide and nitrous oxide. Changes in management can reduce the release of these greenhouse gases, and soil can further be used to sequester some of the CO2 in the atmosphere.