This website is the digital version of the 2014 National Climate Assessment, produced in collaboration with the U.S. Global Change Research Program.

For the official version, please refer to the PDF in the downloads section. The downloadable PDF is the official version of the 2014 National Climate Assessment.

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Welcome to the National Climate Assessment

The National Climate Assessment summarizes the impacts of climate change on the United States, now and in the future.

A team of more than 300 experts guided by a 60-member Federal Advisory Committee produced the report, which was extensively reviewed by the public and experts, including federal agencies and a panel of the National Academy of Sciences.

Explore the effects of climate change
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Agriculture

Climate disruptions to agriculture have been increasing and are projected to become more severe over this century.

Explore agriculture.

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Introduction

Some areas are already experiencing climate-related disruptions, particularly due to extreme weather events. While some U.S. regions and some types of agricultural production will be relatively resilient to climate change over the next 25 years or so, others will increasingly suffer from stresses due to extreme heat, drought, disease, and heavy downpours. From mid-century on, climate change is projected to have more negative impacts on crops and livestock across the country – a trend that could diminish the security of our food supply.

Key Message: Increasing Impacts on Agriculture

Climate disruptions to agricultural production have increased in the past 40 years and are projected to increase over the next 25 years. By mid-century and beyond, these impacts will be increasingly negative on most crops and livestock.

Key Message: Weeds, Diseases, and Pests

Many agricultural regions will experience declines in crop and livestock production from increased stress due to weeds, diseases, insect pests, and other climate change induced stresses.

Key Message: Extreme Precipitation and Soil Erosion

Current loss and degradation of critical agricultural soil and water assets due to increasing extremes in precipitation will continue to challenge both rainfed and irrigated agriculture unless innovative conservation methods are implemented.

Key Message: Heat and Drought Damage

The rising incidence of weather extremes will have increasingly negative impacts on crop and livestock productivity because critical thresholds are already being exceeded.

Key Message: Rate of Adaptation

Agriculture has been able to adapt to recent changes in climate; however, increased innovation will be needed to ensure the rate of adaptation of agriculture and the associated socioeconomic system can keep pace with climate change over the next 25 years.

Key Message: Food Security

Climate change effects on agriculture will have consequences for food security, both in the U.S. and globally, through changes in crop yields and food prices and effects on food processing, storage, transportation, and retailing. Adaptation measures can help delay and reduce some of these impacts.

Agriculture

man inspecting wheat; farmer with corn ©iStockPhoto.com/ small_frog; ©iStockPhoto.com/ ValentinRussanov

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 social and economic systems. Climate change has the potential to both positively and negatively affect the location, timing, and productivity of crop, livestock, and fishery systems at local, national, and global scales.

The U.S. produces nearly $330 billion per year in agricultural commodities.6 This productivity is vulnerable to direct impacts on crop and livestock development and yield from changing climate conditions and extreme weather events, and indirect impacts through increasing pressures from pests and pathogens. Climate change has the potential to both positively and negatively affect agricultural systems at local, national, and global scales. Climate change will also alter the stability of food supplies and create new food security challenges for the U.S. as the world seeks to feed nine billion people by 2050.

Crop Yields Decline under Higher Temperatures Crop Yields Decline under Higher Temperatures Details/Download

The agricultural sector continually adapts through a variety of strategies that have allowed previous agricultural production to increase, as evidenced by the continued growth in production and efficiency across the United States. However, the magnitude of climate change projected for this century and beyond, particularly under higher emissions scenarios, will challenge the ability of the agriculture sector to continue to successfully adapt.

Key Climate Variables Affecting Agricultural Productivity

Projected Changes in Key Climate Variables Affecting Agricultural Productivity

Change in Frost-free Season Length
Change in Number of Consecutive Dry DaysChange in Number of Hot Nights

Frost-free season is projected to lengthen across much of the nation. Taking advantage of the increasing length of the growing season and changing planting dates could allow planting of more diverse crop rotations, which can be an effective adaptation strategy.

The annual maximum number of consecutive dry days (less than 0.01 inches of rain) is projected to increase, especially in the western and southern parts of the nation, negatively affecting crop and animal production. The trend toward more consecutive dry days and higher temperatures will increase evaporation and add stress to limited water resources, affecting irrigation and other water uses.4

Hot nights are defined as nights with a minimum temperature higher than 98% of the minimum temperatures between 1971 and 2000. Such nights are projected to increase throughout the nation. High nighttime temperatures can reduce grain yields and increase stress on animals, resulting in reduced rates of meat, milk, and egg production.5

Projections are shown for 2070-2099 as compared to 1971-2000 under an emissions scenario that assumes continued increases in heat-trapping gases (A2). (Figure source: NOAA NCDC/CICS-NC).

Details/Download

References

  1. Changnon, S. A., and D. Winstanley, 1999: Long-Term Variations in Seasonal Weather Conditions and Their Impacts on Crop Production and Water Resources in Illinois. Water Survey Research Report RR-127. Illinois State Water Survey, Dept. of Natural Resources. URL

  2. Colby, B., and P. Tanimoto, 2011: Using climate information to improve electric utility load forecasting. Adaptation and Resilience: The Economics of Climate-Water-Energy Challenges in the Arid Southwest, B.G. Colby and G.B. Frisvold, Eds., RFF Press, 207-228.

  3. Karl, T. R., B. E. Gleason, M. J. Menne, J. R. McMahon, R. R. Heim, Jr., M. J. Brewer, K. E. Kunkel, D. S. Arndt, J. L. Privette, J. J. Bates, P. Y. Groisman, and D. R. Easterling, 2012: U.S. temperature and drought: Recent anomalies and trends. Eos, Transactions, American Geophysical Union, 93, 473-474, doi:10.1029/2012EO470001. URL

  4. Mader, T. L., 2012: Impact of environmental stress on feedlot cattle. Western Section, American Society of Animal Science, 62, 335-339. URL

  5. Mishra, V., and K. A. Cherkauer, 2010: Retrospective droughts in the crop growing season: Implications to corn and soybean yield in the midwestern United States. Agricultural and Forest Meteorology, 150, 1030-1045, doi:10.1016/j.agrformet.2010.04.002.

  6. U.S. Census Bureau, 2012: The 2012 Statistical Abstract: Agriculture. 533-558 pp., U.S. Census Bureau, U.S. Department of Commerce, Washington, D.C. URL

The National Climate Assessment summarizes the impacts of climate change on the United States, now and in the future.

A team of more than 300 experts guided by a 60-member Federal Advisory Committee produced the report, which was extensively reviewed by the public and experts, including federal agencies and a panel of the National Academy of Sciences.

United States Global Change Research Program logo United States Global Change Research Program participating agency logos