Climate Change Brings Opportunities to Predict Droughts, Floods Earlier
Human-driven climate change is increasing the frequency of droughts and extreme weather events in vulnerable regions like the eastern Horn of Africa, where up to 31 million people are currently in need of humanitarian food assistance.
But in a new paper published in Earth’s Future, scientists with the Famine Early Warning Systems Network (FEWS NET) explain how they are using climate change-driven insights to their advantage to predict extreme weather events long before they occur, giving organizations like USAID adequate time to respond.
“Understanding that climate change makes extremes more frequent is really empowering because now we can try to anticipate those bad effects,” Chris Funk, director of the University of California, Santa Barbara (UCSB) Climate Hazards Center (CHC) said. “Years of research have led to a deep understanding of these extremes, opening the door to very successful, long-lead forecasts.”
In the Earth’s Future paper, Funk and scientists with other FEWS NET partner organizations — including the East African Intergovernmental Authority on Development (IGAD) Climate Prediction and Applications Center — explain how climate change and La Niña are interacting to amplify natural sea surface temperature gradients. Because most energy absorbed from the sun goes into our oceans, the total amount of ocean heat content is growing at a rapid pace. Sea surface temperature gradients, which reflect changes in temperature across the ocean’s surface from one location to another, greatly affect the climate in many countries.
“We can think of tropical sea surface temperatures as being like electricity moving through the climate system. When they get too high, they deliver a jolt to the overlying atmosphere, and those jolts can shift climate conditions thousands of miles away, increasing the chances of a drought or flood, ” Funk explained. “Climate change is directly affecting sea surface temperatures by rapidly adding heat to the oceans, which increases the intensity of events like El Niños and La Niñas. This can impact many nations bordering the Indian and Pacific Oceans, including many FEWS NET-monitored countries.”
FEWS NET scientists have used this technique of analyzing sea surface temperature gradients to accurately predict numerous droughts and floods since 2016. Most notably, FEWS NET began ringing alarm bells in mid-2020, months before the start of a record-breaking five consecutive seasons of drought in the eastern Horn of Africa. FEWS NET’s warnings helped motivate USAID’s humanitarian response of more than $1.8 billion in the region.
The eastern Horn of Africa’s position makes it uniquely susceptible to climate hazards driven by sea surface temperatures in the Indian and Pacific Oceans. According to the Earth’s Future paper, climate change is causing extreme, but often predictable, sea surface temperatures to arrive more frequently. When this happens in the context of La Niñas, we see increased rains above the eastern Indian Ocean and western Pacific, and at the same time, decreased rains over the eastern Horn of Africa.
“We’ve worked for more than a decade to understand this relationship between human-driven climate change, La Niña and extreme weather events,” Funk said. “We have a good track record of accurately predicting eastern East African droughts as a result of these interactions, and we hope the Earth’s Future paper boosts confidence in our forecasts so they can be used to justify more proactive measures.”
While this commentary focused on La Niñas, the same logic applies to other climate extremes, like El Niños, during which we see increased rains in East Africa, in addition to frequent droughts over Southern Africa and northern Ethiopia.
According to a set of recommendations posited by the authors of the Earth’s Future paper, trust, urgency and accuracy are needed to effectively utilize long-lead forecasts to minimize deaths and other negative outcomes of extreme climate events. The recommendations highlight the importance of investing in African-led early warning systems and strengthening linkages between early warning systems and agricultural development efforts to support long-term adaptation, thereby reducing the chronic need for billions of dollars in reactive assistance.
“To reduce the impacts of climate extremes, we need to look for opportunities,” CHC specialist and operations analyst, Laura Harrison, told the UCSB Current. “We need to pay attention to not just how climate is changing, but how these changes can support more effective predictions for droughts and for advantageous cropping conditions. As a community, we also need to foster communication about successful resilience strategies.”
One way this is already happening, Harrison explained, is through a partnership between PlantVillage and iShamba to deliver rain forecasts to the mobile phones of more than 500,000 Kenyan smallholder farmers.
“Communication technologies are offering important steps forward in the delivery of forecast information, as well as expert guidance on crop health issues,” Harrison said. “To make the most out of good rainfall conditions when they are forecast also means strengthening household access to resources that can improve yields, soil organic material and water storage.”
Looking toward the future, effective strategies to deal with climate change and droughts will likely be highly diverse, conditional to ecosystems and communities, and informed by both tradition and technology, Harrison noted.
FEWS NET scientists expect strong sea surface temperature gradient events to increase by more than 50% by 2050, which will likely lead to a higher frequency of poor rainy seasons in the eastern Horn of Africa. In addition, increasing air temperatures will continue to contribute to both droughts and floods, all while increases in population, food prices and water scarcity are expected to further drive food insecurity.
As a final call to action in the paper, Funk and co-authors explain that, “investing now in collaborative African climate services, participatory advisory services and proactive risk management will help counter these threatening climate extremes.”
“The good news is that the partnerships strengthened during the development of this commentary are already helping to foster more collaboration between climate scientists and providers of agricultural advisory services,” Funk said. “None of us can tackle these problems alone, but we can work together to help farmers manage climate risks and capitalize on good rainy seasons.”
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