Climate change could raise food insecurity risk
Weather extremes caused by climate change could raise the risk of food shortages in many countries, new research suggested.
The study, led by the University of Exeter, examined how climate change could affect the vulnerability of different countries to food insecurity — when people lack access to a sufficient quantity of affordable, nutritious food, phys.org wrote.
Scientists looked at the difference between global warming of 1.5°C and 2°C (compared to pre-industrial levels) and found that — despite increased vulnerability to food insecurity in both scenarios — the effects would be worse for most countries at 2°C.
The study looked at 122 developing and least-developed countries, mostly in Asia, Africa and South America.
Professor Richard Betts, Chair in Climate Impacts at the University of Exeter, said, “Climate change is expected to lead to more extremes of both heavy rainfall and drought, with different effects in different parts of the world.
“Such weather extremes can increase vulnerability to food insecurity. “Some change is already unavoidable, but if global warming is limited to 1.5°C, this vulnerability is projected to remain smaller than at 2°C in approximately 76 percent of developing countries.”
Warming is expected to lead to wetter conditions on average — with floods putting food production at risk — but agriculture could also be harmed by more frequent and prolonged droughts in some areas.
Wetter conditions are expected to have the biggest impact in South and East Asia, with the most extreme projections suggesting the flow of the River Ganges could more than double at 2°C global warming.
The areas worst affected by droughts are expected to be southern Africa and South America — where flows in the Amazon are projected to decline by up to 25 percent.
The researchers examined projected changes in weather extremes and their implications for freshwater availability and vulnerability to food insecurity.
The team included researchers from the Met Office, the European Commission, the Technical University of Crete, Cranfield University and the Rossby Center in Sweden.
The paper, published in a special issue of the journal Philosophical Transactions of the Royal Society A, is entitled, ‘Changes in climate extremes, fresh water availability and vulnerability to food insecurity projected at 1.5°C and 2°C global warming with a higher-resolution global climate model.’ Africa’s Sahara Desert has grown 10 percent in nearly 100 years, according to a new study by scientists at the University of Maryland.
The Sahara, which is the world’s largest warmweather desert and roughly equal in size to the contiguous US with 3.6 million square miles, has expanded by 11 percent to 18 percent depending on the season, UPI wrote.
The study was published in the American Meteorological Society’s Journal of Climate.
The researchers analyzed annual rainfall data recorded throughout Africa until 2013. When the average rainfall is less than four inches of rain per year or less, an area is considered a desert.
Ming Cai, a program director in National Science Foundation’s Division of Atmospheric and Geospace Sciences, which funded the research, said, “The trends in Africa of hot summers getting hotter and rainy seasons drying out are linked with factors that include increasing greenhouse gases and aerosols in the atmosphere.
“These trends have a devastating effect on the lives of African people, who depend on agriculturebased economies.”
The biggest increases occurred during summers, when the Sahara increased 16 percent over the 93year span.
As is the case with other deserts, the boundaries of the Sahara fluctuate between dry winters and wetter summers.
The largest differences occurred along the Sahara’s northern and southern boundaries.
The researchers believe one-third of the expansion can be attributed to human-caused climate change and the remaining two-thirds associated with climate cycles.
Senior author Sumant Nigam, an atmospheric and ocean scientist at Maryland, said, “Deserts usually form in the subtropics because of what’s called Hadley circulation, through which air rises at the equator and descends in the subtropics.
“That circulation has a drying effect. Climate change is likely to widen this Hadley circulation, causing the northward advance of subtropical deserts. The southward creep of the Sahara suggests that additional mechanisms are at work.”
Researchers want to further explore those potential causes.
Lead author Natalie Thomas, a researcher at Maryland, said, “Our next step will be to look at what’s driving these trends, for the Sahara and elsewhere.”
Because of less land with adequate rainfall, the researchers said it will have devastating consequences on growing crops.
Thomas said, “We’ve already started looking at seasonal temperature trends over North America, for example.
“Here, winters are getting warmer but summers are about the same. In Africa, it’s the opposite — winters are holding steady but summers are getting warmer. So the stresses in Africa are already more severe.”
Lake Chad is a semi-arid transition zone between the Sahara and fertile savannas farther south.
Nigam said, “The entire Chad Basin falls in the region where the Sahara has crept southward, and the lake is drying out.
“It’s a very visible footprint of reduced rainfall not just locally, but across the whole region. It’s an indicator of declining water in the Chad Basin.”