Drought, flooding & pests could halve the agricultural output of S.E. Asia
by Stephen Lacey
Two of Southeast Asia’s most valuable crops — rice and cassava — are under pressure from multiple, simultaneous threats fueled by climate change. The Research Program on Climate Change, Agriculture and Food Security has issued two pieces of research highlighting the devastating impacts that extreme weather is having on Asia’s agriculture.
The first piece of research looks at the impact of floods and droughts on Southeast Asia’s rice crops. According to researchers, severe flooding and drought throughout the region could reduce agricultural yields by up to 50% in the next three decades.
So-called “weather whiplash” — back-to-back extreme weather events — is already hitting rice crops hard. In 2010, Thailand experienced $450 million in crop damages due to a severe drought. The following year, flooding again decimated rice crops, causing $40 billion in damages throughout the country’s economy. With Southeast Asia now the “rice bowl” of the world, acceleration of warming-fuelled extreme weather would make the local and global economic impact of these disasters enormous.
South and Southeast Asia are home to more than one-third of the world’s population and half of the world’s poor and malnourished people. Absent new approaches to food production, climate change in this region is expected to reduce agriculture productivity by as much as 50% in the next three decades. And with agriculture serving as the backbone of most economies in the region, such plunging yields would shake countries to the core.
Now, the growing variability between seasons has increased pressures on water supplies, while at the same time rising sea levels are tainting freshwater supplies with high levels of salinity. This troublesome combination is putting Asia’s tremendous rice production at risk. Rice in Asia is grown in vast low-lying deltas and coastal areas such as the Mekong River delta, which produces more than half of Vietnam’s rice; the rise in sea level from climate change will change the hydrology and salinity of these fields. Moreover, some of the major river basins—including the Chao Phraya in Thailand and the Red in Vietnam—are considered “closed” because all of the water flow has been claimed.
Warming temperatures and changing weather patterns are also spawning new outbreaks of pests in the region, threatening the multi-billion dollar cassava industry. Cassava is a root used for a variety of food products, animal feed and biofuels. Last year, Thailand exported about $1.4 billion worth of cassava—roughly 60% of the country’s exports. Cassava farmers in the region already deal with multiple types of pests. But researchers at the International Center for Tropical Agriculture say new types of non-native pests are emerging:
For cassava in Southeast Asia, mealybugs and whiteflies are already endemic in the region. But new threats, such as the tiny green mite (Mononychellus mcgregori), are already emerging, says the research, published recently in the scientific journal Tropical Plant Biology.
“The cassava pest situation in Asia is pretty serious as it is. But according to our studies, rising temperatures could make things a whole lot worse. One outbreak of an invasive species is bad enough, but our results show that climate change could trigger multiple, combined outbreaks across Southeast Asia, Southern China and the cassava-growing areas of Southern India. It’s a serious threat to the hundreds of thousands of smallholder farmers for whom cassava is a lifeline, and their main source of income.”
Tony Bellotti, cassava entomologist
The combined impact of extreme weather and pest outbreaks could be catastrophic for the region’s agricultural sector. With more than half a billion people, Southeast Asia is one of the fastest growing regions in the world.