Back-to-back La Niña events spark two consecutive seasons of below-average precipitation, a third such season is forecast for 2022/2023

As the United States works to mitigate the effects of a severe drought in its own southwest, and while the international community ramps up relief efforts for the ongoing drought in the eastern Horn of Africa, the Famine Early Warning Systems Network (FEWS NET) is warning of another extreme, multi-season drought happening in Afghanistan.

All three regions — the southwestern United States, the eastern Horn of Africa and Afghanistan — are currently experiencing extreme droughts as a result of La Niña events, which have been exacerbated by climate change and rising global temperatures.

“La Niña events modify the atmospheric circulation, and that leads to high pressure over the region, which reduces the number of storms that move through the country and results in below-average precipitation,” NOAA research meteorologist and FEWS NET principal investigator Andrew Hoell explained. “Climate change is a modifier that helps make droughts worse.”

Climate change intensifies hydroclimatic impacts related to La Niña events in two major ways. First, climate change increases sea surface temperatures in the western Pacific and Indian Oceans, which increases the likelihood of far below-average precipitation due to the resulting larger contrast between temperatures across the Pacific Ocean.

Second, as climate change leads to rising temperatures, there is a greater demand for moisture by the atmosphere and less available moisture in and on the land surface. The effects of both increased temperatures and increased dryness can make coping with La Niña-induced droughts particularly challenging.

Over the last two years, Afghanistan has experienced two consecutive seasons of below-average precipitation, and a third failed wet season is expected between October 2022-May 2023. According to Hoell, because another La Niña event is forecast later this year, there is about a 70% chance of below-average precipitation across the country.

While Afghanistan experienced a significant multi-season drought in the late 1990s and early 2000s, Hoell said the current drought situation is unprecedented.

“In the broader context of conditions since the late 1990s, yeah, it’s beyond unprecedented,” he said. “In the grand scheme of things, in terms of historical drought, Afghanistan’s historical drought is every bit as bad as what’s going on over East Africa.”

The combination of consecutive La Niña events and rising global temperatures as a result of climate change has left little room for soil moisture and groundwater recovery in Afghanistan. The latest precipitation observations based on Climate Hazards Group InfraRed Precipitation with Station Data (CHIRPS) — a dataset that estimates precipitation — shows that cumulative precipitation for the 2021/2022 wet season was below average across a majority of the country and significantly below average in many northern, northeastern and central areas. The cumulative effects of consecutive below-average rainy seasons have led to poor vegetation and pasture conditions, which are expected to severely impact agricultural and pastoral livelihoods.

“Drought is what we call a cascading hazard,” Hoell noted. “When you have prolonged precipitation deficits, you then manifest prolonged soil moisture deficits, runoff deficits and water shortage deficits the longer that these precipitation deficits remain. So that’s really what’s happened over the last few years.”

Reservoirs and other groundwater sources are diminishing, and the people of Afghanistan now have fewer water resources to help cope with the ongoing, multi-season drought. An additional failed rainy season later this year could lead to further degradation of the scarce water resources that remain.

Even if the upcoming wet season unexpectedly performs well — of which there is about a 20% probability, according to Hoell — the cumulative effects of the past two failed rainy seasons would still not be mitigated. Adequate rainfall between October 2022-May 2023 would help to replenish the amount of moisture in Afghanistan’s soil, but there would need to be many consecutive average or above-average precipitation seasons to recharge reservoirs, and a five or 10-year period of successful rainy seasons to recover groundwater levels.

“The climate does vary, it is cyclical to some degree, and that right there is perhaps the hope for, not the 2022/2023 season that we’re coming on, but 2023/2024,” Hoell said. “The problem there is, how long can you wait, though, right? How much can you bear, how much can you sustain?”

While climate change has undoubtedly played a role in exacerbating the severity of La Niña-related droughts in Afghanistan — by decreasing water resources, elevating global ocean temperatures and increasing demand of moisture by the atmosphere — Hoell explained that La Niña events themselves are not atypical phenomena.

“There is a component of this drought that is natural in the sense that it is a La Niña event. La Niña events happened in the past and this is what we know them to produce in Southwest Asia,” Hoell said. “What I would imagine here, and looking at the time series of drought, is that at some point there will be at least a little bit of recovery. Can conditions be that bad for that long? Probably not. But at the same time, this is perhaps a harbinger of things to come.”

FEWS NET will continue to monitor the drought situation in Afghanistan. Follow @FEWSNET on Twitter and Facebook for the latest news, and subscribe to receive alerts when new reports are published.