Drought special part 2. Hungry for drought knowledge


Today I feature the second article of the recent drought package in Science.

The hunger forecast by staff writer Paul Voosen covers the science behing the Famine Early Warning Systems Network (you may recall that I featured FEWS predictions in a recent blog post).

The motivation?

The forecasts are needed more than ever. From 2015 to 2019, the global number of people at risk of famine rose 80% to some 85 million—more than the population of Germany. Wars in Yemen, Syria, and Sudan are the biggest driver of the spike. Global warming, and the droughts and storms it encourages, also plays a role.

This is a bit sensationalist for my taste. From Our World in Data:

… the parts of the world that continue to be at risk of famine represent a much more limited geographic area than in previous eras, and those famines that have occurred recently have typically been far less deadly.

Nonetheless, the article is worth reading, if only for the update on some of the recent major breakthroughs in drought prediction.

1. There’s an important phenomenon called the East African Climate Paradox.

From Wainwright et al., 2019:

An observed decline in the Eastern African Long Rains from the 1980s to late 2000s appears contrary to the projected increase under future climate change. This “Eastern African climate paradox” confounds use of climate projections for adaptation planning across Eastern Africa.

2. There’s an oceanic feature known as the “Western V”

The Western V is ”an arc of hot Pacific water that can appear during a La Niña event”, stretching out from Indonesia into the middle of the Pacific.

It provides strong predictive power for drought forecasting:

As water temperatures spike, energetic evaporation saturates low-level winds flowing west from the cool eastern Pacific. The moist winds dump their water over Indonesia—the wet get wetter. The winds, now high and dry, continue their march west across the Indian Ocean and drop down over East Africa, preventing the intrusion of nearby moist ocean air and breaking up rain clouds.

Lastly, my favorite quote from the article. A simple lesson in science communication:

“You’re asking somebody to open up their wallet and spend millions,” [Chris] Funk says. “They’re not just going to do it because you say, ‘Our standardized precipitation forecast is −1.2.’”