As rainfall variability increases, do our graziers have solutions?
Australia isn’t the only country that could be considered a land of “droughts and flooding rains”, as Dorothea Mackellar so eloquently described in her poem, My Country.
“Sweeping plains” across the world are home to graziers and pastoralists whose livelihoods depend almost entirely on rainfall.
In a good year, abundant grass and other forage enable livestock to thrive. In a bad year, pastoralists may need to sell off or cull their livestock. For herders in many countries, poor seasons mean an ongoing search for new pastures in which they can find feed for their animals.
Research published this week in Nature Climate Change shows that year-to-year variability in rainfall has increased in the world’s grazing lands over the last century.
The scientists looked at historical climate data in the major grazing regions of the world from 1901 to 2014.
An estimated 22 per cent of the planet’s ice-free land is used for livestock grazing.
“Grazing lands are naturally known for their highly variable rainfall; about 25 per cent more year-to-year variability than other lands,” CSIRO chief research scientist Dr Mario Herrero explains.
“This study is showing us that grazing is potentially highly vulnerable to climate change; right across the world, from Australia to Central Asia, sub-Saharan Africa and the Americas.”
Researchers found that 49 per cent of global grazing lands experienced significant increases in year-to-year rainfall variability and 31 per cent experienced significant decreases.
“What is particularly worrying is that the areas especially affected by the increasing variability trends are areas where livestock grazing is important for food access and economies,” says Cecile Godde, PhD candidate with CSIRO.
There are around 600 million rural poor who rely on livestock for their livelihoods.
“If a region such as the Sahel in Africa experiences a lot of variation in rainfall, pastoralists will not be able to maintain their herds and this could exacerbate poverty and malnutrition.”
In Australia, the researchers say, we have a long history of climate variability, which has meant our graziers have found innovative ways to adapt and thrive in the face of adversity.
In recent times, graziers have tended to alter the number of livestock they keep in response to how much feed is available. They also hold off on restocking after droughts to give pastures enough time to recover.
“Strategies such as these will become ever more vital as our climate becomes increasingly variable,” says Dr Herrero.
The research has been a collaboration by scientists from CSIRO, University of Minnesota, University of Arizona and Federal University of Goiás in Brazil, funded by the Gordon and Betty Moore Foundation and the Belmont Forum/FACCE-JPI funded DEVIL project (Delivering Food Security from Limited Land).
Read more about the impact of climate change on agriculture in Environment Reports: Food matters.