Climate Postcards: Agriculture

• Higher global temperatures and drought induce crop heat stress, dry out the soil, and promote weeds.
• Heat stress limits the growth, metabolism, and productivity of plants. High nighttime temperatures can reduce grain yields.
• Heat stress makes plants more susceptible to mold growth. Corn, peanuts, cereal grains, and fruit are especially susceptible to mold growth and mycotoxin production. Mycotoxin can result in illness and death.Although the U.S. has regulations in place to prevent mycotoxins from entering the food supply, it may be difficult to manage as climate change continues.
• Rising temperatures and CO2 concentration favor the growth and can increase the range of weeds. If farmers respond by increasing their use of herbicides, that can cause some weeds to become herbicide-resistant.

• Animals are also affected by high temperatures.
  • High nighttime temperatures increase stress on animals. This can result in reduced rates of meat, milk, and egg production.
  • Pollinators, like bees, are also affected by higher temperatures, as they can suffer from heat exhaustion and decreased immune response.

• Climate change can cause dramatic reductions in water availability, such as droughts, depletion of groundwater aquifers, and uneven distribution of rainfall.

• • Droughts reduce crop production. In the U.S. during 2012, severe drought impacted 67% of cattle production and about 70-75% of corn and soybean production. Soybean yields in 2012 were the lowest since 2003.

• • An intense downpour falling on dehydrated soil can cause topsoil runoff and damage growing plants.

As levels of CO2 increase, plant growth will spike—but nutritional value may fall.

• Studies show that protein concentrations in barley, wheat, rice, and potato will decline by 6% to 15% when grown in the CO2 levels projected for 2100.

• Protein concentration may be replaced with elevated levels of carbohydrates (starch and sugars).

• In response to high levels of atmospheric CO2, cereal and staple crops will likely have lower concentrations of many nutrients important to human health, including iron, zinc, calcium, magnesium, copper, sulfur, and phosphorous.

How does food production affect climate change?

• In 2011, global livestock production produced 39% of the world’s methane emissions, more than synthetic fertilizer or deforestation. Methane is a greenhouse gas 86 times more potent than CO2 over its first 20 years in the atmosphere.
• Beef and milk contribute 41% and 20% of the livestock sector’s Greenhouse Gas (GHG) emissions.
• Pork contributes 9% of the livestock sector’s GHG emissions. Poultry and eggs contribute 8%.

Certain populations are particularly vulnerable

• Reductions in food yield and food quality, as well as climate-related disturbances to transportation and distribution, can severely affect vulnerable populations’ access to sufficient quantities of nutritious, affordable food.
• Growing urban populations that rely heavily on the global food market will be vulnerable to supply issues.
• Losses of nutritional value and access to food will be felt disproportionately by infants, children, pregnant women, the elderly, low-income populations, agricultural workers, and those with weakened immune systems.