The impacts of climate change on grazing lands and the livestock operations that depend on them will vary by region, type of grazing land, vegetation community, and the type of livestock. These impacts are superimposed upon other factors such as land ownership, historical and current management, demographic changes and access to USDA programs.
Rangelands cover an area of 405.8 million acres or 21% of the U.S. surface area. In the Western states, rangelands are predominantly Federally-owned lands, whereas over the Great Plains, rangelands are privately-owned. Pasturelands are also privately owned and cover 121.1 million acres (6% of the U.S. surface area); pasturelands are more common in the wetter half of the US, to the east of the 97th meridian. Rangelands and pasturelands are both used for grazing but the difference between the two is that rangelands support natural (and usually native) ecosystems while pasturelands are highly managed, cultivated systems.
For rangelands, warming temperatures and precipitation changes may change competitive interactions between plant species, favoring invasive species over native species. Rising CO2 is likely to enhance rangeland productivity while improving water use efficiency, but this could also benefit undesirable species over preferred native species. In some areas, such as the Northern Plains, rising temperatures and a longer growing season could improve forage production, whereas in others rising temperatures exacerbate drought by driving increased losses to evaporation. A trend to more extreme precipitation events will lead to increased flooding and erosion, especially in arid Southwest. Increased fire events are also likely, especially where invasives such as cheatgrass become dominant.
Warming temperatures and a longer growing season may improve productivity in pasturelands, but where pastures are rain-fed, less reliable precipitation could offset the benefits of a longer growing season. Where pastures are irrigated, commonly in the western states, warmer temperatures will increase demand for already over-stretched water resources.
Climate change may also directly impact unsheltered livestock. Livestock can be vulnerable to sudden or dramatic environmental changes. Lack of conditioning to rapidly changing or harmful weather events can result in catastrophic deaths.
Responding to Climate Change
Three elements that can impact the success of grazing operations include the seasonal distribution and quantity of forage, the inter-annual reliability of forage production, and forage nutritional value. Using conservative stocking rates, varied season of grazing, optimizing herd size and composition, identifying reserve forage, strategic distribution of water, proactive vegetation management and changes in enterprise structure are examples of rangeland management practices that can help livestock producers adapt to the negative impacts of climate change. Most of these practices are also relevant to pasture systems. However, because pasture systems are highly managed and often smaller in size than rangeland systems, there is more latitude in developing resilient management techniques that sometimes have more in common with cropland agriculture. The USDA Natural Resources Conservation Service offers conservation programs to assist producers in adopting technologies that enhance the resilience and productivity of their grazing lands.
USDA’s Climate Hubs aim to better prepare farmers with adaptive responses to climate change by working with producers and partners to deliver science-based, region-specific information and technologies to enable climate-smart decision making. By working with USDA's Climate Hubs, grazing lands producers will be more prepared to adapt to a changing climate.
This page features information from the following sources:
Izaurralde, R.; Thomson, A.; Morgan, J.; Fay, P.; Polley, H.; Hatfield, J., Climate Impacts on Agriculture: Implications for Forage and Rangeland Production. Agronomy Journal 2011, 103 (2), 371-381.
Joyce, L.; Briske, D.; Brown, J.; Polley, H.; McCarl, B.; Bailey, D., Climate Change and North American Rangelands: Assessment of Mitigation and Adaptation Strategies. Rangeland Ecology & Management 2013, 66 (5), 512-528.
McCollum, D. W.; Tanaka, J. A.; Morgan, J. A.; Mitchell, J. E.; Fox, W. E.; Maczko, K. A.; Hidinger, L.; Duke, C. S.; Kreuter, U. P., Climate Change and North American Rangelands: Assessment of Mitigation and Adaptation Strategies. Ecosystem Health and Sustainability 2017, 3 (3), 13.