Improved Forecasting Tools Offer Early Warning for Drought

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There are 2.2 million people in Somalia at risk for malnutrition this year.

The reasons are myriad, but the ravages of drought – crop failures, food shortages, spiking food prices - are primary drivers of that risk.

Figure showing FEWS NET monitoring system workflow and climate extremes

Figure showing stages of Famine Early Warning Systems Network work flow and time series of El Nino-Southern Oscillation (ENSO) and West Pacific Warming Mode (WPWM) events.

Fortunately, that much was known and reported by the Famine Early Warning Systems Network (FEWS NET) as early as April. The early drought forecast, built from weather modeling and rainfall observations collected after Cyclone Idai struck southern Africa, offered aid organizations the world over an opportunity to plan for and respond to expected troubles in the Horn of Africa.

Even after unexpected late season rains, the FEWS NET food security outlook hovers between emergency and crisis conditions for Somalia. As a result, aid organizations have begun to step in with humanitarian assistance.

It wasn’t always possible to pinpoint drought dangers with such precision.

That it happened so quickly speaks to the evolving, adaptive nature of FEWS NET’s Drought Early Warning System (DEWS), a key feeder for the multi-agency organization’s data stream. The advancements of FEWS NET’s early warning tools and predictive strategies were outlined in detail for the first time recently in an article from lead author Chris Funk of the U.S. Geological Survey’s Earth Resources Observation and Science (EROS) Center and dozens of co-authors across the FEWS NET partnership.

EROS provides a leadership role in FEWS NET as a both a source of interpretive expertise and a hub for the agro-climatic outlooks used by analysts around the world to inform the monthly FEWS NET food security outlook reports that can trigger humanitarian aid.

“A key part of this is how we piece together all of this data — satellite data, the weather forecasts that are coming in from NOAA, the hydrologic simulations that are coming from NASA and so on — to get an integrated look at how a situation might progress,” said Funk, who works for EROS from a home base at the University of California-Santa Barbara’s Climate Hazards Center.

“We help form the sharp tip of the spear, where we’re trying to really translate that information into assessments of food shocks, which in turn inform effective famine early warning,” Funk said.

The FEWS NET drought warning system integrates three primary sources of predictive skill: ocean temperatures, which impact seasonal rainfall patterns worldwide; atmospheric observations, which offer insight on heat and rainfall at one- to two-week intervals; and land surface measurements, which track vegetation health and soil moisture throughout the growing season.

The warnings come in stages and begin with history. In East Africa, for example, rainfall records show a steady decline in rainfall since the late 1990s, with shorter recovery periods between droughts. Climate patterns offer insight as to why: The frequency of intense, ocean-warming El Nino-Southern Oscillation (ENSO) events has ticked up, and each ENSO event has been followed by a West Pacific Warming Mode (WPWM) increase. That increase helps maintain high sea surface temperatures in the Western Pacific the following season.

Those warm waters translate into lower rainfall across East Africa. That’s meant back-to-back droughts for the region following the El Nino events of 1997-98, 2009-10, and 2015-16.

The trends help define high risk areas, and help explain why 80 million people in the developing world face food insecurity despite growing global wealth.

Figure showing FEWS NET drought warning stages

Figure showing Famine Early Warning Systems Network drought early warning stages.

“Essentially, we’re seeing kind of a seesaw between these two modes of variability, and this can completely wreak havoc,” Funk said. “During the last El Nino we saw extreme drought in and food insecurity in Ethiopia and Southern Africa in 2015 and 2016, followed by severe drought and food shortages in Kenya and Somalia in 2017.”

That context helps guide drought early warning systems. When sea surface temperatures suggest high risk before the season, DEWS can raise its alert level to one of concern. Low mid-season rainfall from March to July might raise the alert level further. The alert level could again rise based on observed rainfall totals and vegetation health data collected through August. In the fall, seasonal rainfall totals are placed into a historical context through satellite-based assessments of season-long crop damage, and the alert is once again updated.

Tracking through those stages for Ethiopia in 2015 tagged that year’s drought as the country’s worst in 50 years. The alerts and the response they sparked from the international community kept the situation from morphing into the sort of famine that took place in the 1980s, when more than one million people starved. That tragedy helped inspire the creation of FEWS NET.

“A lot of us remember the horrible famine of 1984. This drought in 2015 was every bit as bad, but the response was much better and the mortality was far lower,” Funk said.

One needn’t look to comparisons with the 1984 famine to see improvements, however. Since 2011 — a deadly year for famine in Somalia — FEWS NET has improved its precipitation data sets, vegetation and precipitation monitoring resources, land surface modeling, and tools to blend datasets together, many of which are integrated into an Early Warning Explorer tool for online viewing by the analysts who write Food Security Outlook reports — or anyone else in the world.

The value of those enhancements was apparent by 2017. The 2011 drought in Somalia, exacerbated by armed conflict, killed 260,000 people.  In 2017, appeals for food aid from FEWS NET appeared in March, preventing runaway food price increases and starvation deaths.

“Recognizing the Famine Early Warning Systems Network: Over 30 Years of Drought Early Warning Science Advances and Partnerships Promoting Global Food Security” appears in the June 2019 issue of the Bulletin of the American Meteorological Society.

Click here to read the full article.

Click here to learn more about FEWS NET.

Click here to read about how FEWS NET analysts create food security outlooks

 

 

 

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