Is the climate crisis impacting Sahara dust storms?

Dust clouds expected to impact Florida and parts of the Caribbean this weekend

Vast clouds of dust from the Sahara desert are moving across the Atlantic Ocean and could make for darkened skies and poor air quality in the Caribbean and US southeast in the coming days, according to forecasters.

Two large plumes were spotted from space by a US government satellite on Thursday.

The smaller of the clouds is expected to arrive in Florida on Saturday and move across coastal areas of Texas, Louisiana, Mississippi, and Alabama in the following days, according to AccuWeather.

A second, larger cloud is forecast to impact the Caribbean on Sunday, and make it to Florida by Tuesday.

The clouds will likely darken skies with public officials warning those with allergies and respiratory problems that the spike in small-particle pollution could exacerbate health conditions, and may mimic Covid-19 symptoms.

The forecast follows a spell of dramatic, climate crisis-inflected weather in the US after smoke from hundreds of Canadian wildfires led to plummeting air quality ratings across the country in the past month.

Scientists and health experts have long monitored the dust plumes for their impacts.

Are the Sahara dust storms a new phenomenon?

No. Sand and dust storms occur annually when powerful, hot winds, sweep across loose soils on arid land. They can cause death and destruction in desert regions. For nearly 20 years, the World Meteorological Organization has sent sand and dust storm advisories but it remains tricky to get warnings to people in remote regions.

Although harmful to human health, the dust clouds deliver nutrient-laden minerals from the Sahara, the planet’s largest and hottest desert, to ocean life and vegetation in the Americas and the Caribbean.

In summer 2020, the dust storm was so huge it was dubbed “Godzilla” after winds swept nearly 24 tons from the Sahara to North and South America.

It was so vast that astronauts tweeted photos of the dust cloud from the International Space Station.

Are they being impacted by the climate crisis?

Yes. After “Godzilla” took off in summer 2020, Nasa used satellite data and computer modelling to study the plumes.

While the size of dust clouds vary year to year and decade to decade, scientists predict that the plumes will reach their smallest size in 20,000 years this century due to the climate crisis and ocean heating.

Sea surface temperatures have a direct impact on wind speeds. If warming occurs in the northern Atlantic Ocean, then trade winds are weaker and can carry less desert dust.

Those weaker winds also means bands of tropical rain more easily move into desert regions, keeping the sand damp and less likely to be blown away.

Smaller dust clouds are part of a feedback loop that is increasing global heating. Particles in the air have the ability to reflect the sun so with fewer suspended, more sunlight and heat reach ocean water, causing it to get even warmer.

A dearth of Saharan dust this year may be partially responsible for the cyclical El Niño warming pattern in the Atlantic Ocean, according to climate scientist Dr Michael E. Mann.