Climate Change is a Threat to Health: Food and Hunger
Climate is already disrupting food production, and this frightening trend is expected to increase.
Climate change impacts are anticipated to affect production of the food, feed, fiber, and fuel we use on a daily basis. In addition, higher food prices resulting from diminished food supplies will reduce the ability of people, especially the poor, to consume nutritious diets.
Tensions over scarce resources also aggravate regional and national conflicts, creating additional and persistent health problems.
For more on climate change's impact on agriculture, download PSR's Food and Famine factsheet (PDF)
Rising temperatures hinder crop production by decreasing the rate of photosynthesis, dehydrating plants, and leading to increased survival and range of damaging pests, diseases, and weeds.
While some crops grow more quickly in warmer conditions, for others, fast growth reduces the amount of time seeds have to grow and mature. It is estimated that every 1.8°F increase in global average surface temperature will result in a 10% decline in yields of the word’s major grain crops like corn, soybeans, rice, and wheat
Many perennial plants like fruit trees and grapevines also require a certain number of days of cool temperatures to develop. As the number of cool days decreases, so will yields.
Rising temperatures also affect the water cycle. They cause glaciers to recede, depleting critical water supplies in areas where rainfall is limited. Melting ice caps and expanding seawaters due to rising world temperatures threaten low-lying coastal agriculture. Rising sea levels and storm surges also increase the salinization of soils and aquifers used for irrigation.
Increased temperatures increase the concentration of ground-level ozone, inhibiting photosynthesis and stunting plant growth. Current ozone levels are already suppressing the yields of such crops as peanuts, potatoes, rice, soybeans, and wheat.
Changing precipitation patterns due to climate change have a major impact on agriculture.
Worldwide, the amount of major crop-producing agricultural land affected by drought has risen from five to 10 percent in the 1960s to 15 to 25 percent today. As climate change persists, some regions will experience more frequent, severe, and long-lasting drought that damages agriculture. Irrigated agriculture is also threatened as stored water supplies are depleted.
Other areas will experience more intense rainfall and storms, which can reduce crop productivity through destruction of crops, soil erosion, and increased plant fungal disease.