In February 2018, researchers at the University of Minnesota published a study in Nature Climate Change showing how precipitation variability has increased significantly on 49% of the world’s grazing lands. This variation in precipitation can have detrimental effects not only on the environment as a whole but also on the livelihoods of those who rely on livestock that graze on natural vegetation for food security.
Using climate data from 1901 to 2014, the researchers studied precipitation variability trends and concluded that grazing lands experienced an overall increase in fluctuation, both within and between the years. They also related global satellite measures of vegetation greenness to climate factors to reveal that variation in precipitation is a significant controlling factor of global vegetation productivity. Not only this but in their observations, researchers found that areas with high variation of precipitation support lower livestock densities than less-variable regions.
With this information researchers were able to assess the risks to places where livestock grazing is important to local food security by using global data sets for percent pasture area and market influence to “define areas in which livestock grazing may play a more or less important role in local food availability or the economy.” These findings exhibit how grazing is extremely vulnerable to the potential effects of climate change, which may put the millions of people dependent on livestock for food security at risk.
The researchers concluded that changes in precipitation variability may cause a change in the composition of certain ecosystems and may also threaten the maintenance or expansion of livestock production. However, the impacts of climate change on livestock grazing will not only depend on precipitation variation but also on region, long-term precipitation trends, changes in the timing of snowmelt, the magnitude of precipitation events, and the changes in seasons. With global grazing lands experiencing 25% more year-to-year variability in precipitation than the average global surface land area, the impacts of climate change on these regions could be detrimental to both the livelihoods of humans and the environment overall.
Lindsey L. Sloat, James S. Gerber, Leah H. Samberg, William K. Smith, Mario Herrero, Laerte G. Ferreira, Cécile M. Godde, Paul C. West. Increasing importance of precipitation variability on global livestock grazing lands. Nature Climate Change, 2018; DOI: 10.1038/s41558-018-0081-5