Center for Climate Change and Health Research (CCCHR)

Introduction:

In a groundbreaking review published in *Nature Reviews Earth & Environment*, scientists led by Jasper F. Kok from UCLA have revealed that mineral dust aerosols )tiny rock particles swirling through the atmosphere( are playing a far bigger role in shaping Earth’s climate than previously thought. These gritty travelers, born from the windswept deserts of the Sahara, Asia, and beyond, are not just a nuisance for air quality; they’re key players in the planet’s energy balance, influencing everything from clouds to ice caps and even ocean ecosystems.

Imagine a global dance of dust: every year, about 26 million tonnes of these particles, mostly from North Africa and Asia, fill the atmosphere, making dust the heavyweight champion of aerosols by mass. These particles don’t just stay put they journey thousands of kilometers, with African dust plumes crossing the Atlantic to reach the Americas. Along the way, dust interacts with sunlight and heat, scatters clouds, darkens snow, and even fertilizes oceans, creating a complex web of climatic effects.

The study estimates that dust’s overall effect is a slight cooling of the planet, with a radiative effect of about -0.2 W/m², though the uncertainty is large (-0.7 to +0.3 W/m²). This cooling comes from dust scattering sunlight back to space, outweighing its warming effects, like absorbing heat or reducing reflective clouds. But the story gets spicier: since pre-industrial times, global dust levels have surged by 55% (±30%) , largely due to increased emissions from Asia and North Africa, driven by human activities like agriculture and land use changes. This dust boom has produced a cooling force of -0.07 W/m², subtly counteracting greenhouse warming a factor current climate models often miss, skewing predictions.

Dust’s influence is a tale of opposites. It cools by scattering sunlight over dark oceans but warms when it absorbs heat over bright deserts or snow. It seeds clouds, sometimes making them brighter and longer-lasting, yet can also thin high-altitude cirrus clouds, cooling the planet further. When dust settles on snow, it darkens surfaces, accelerating melting in places like the Rockies or Tibetan Plateau, triggering a warming feedback. Meanwhile, dust delivers iron to nutrient-starved oceans, boosting plankton growth and sucking CO₂ from the air a process that’s intensified with rising dust and pollution since the 1800s, contributing a cooling effect of -0.12 W/m².

Conclusion  :Yet, the future of dust is murky. Climate models disagree wildly on whether dust will increase or decrease, as it depends on tricky factors like wind patterns, rainfall, and human land use. This uncertainty, coupled with poor representation of dust in models, means we’re missing a critical piece of the climate puzzle. The researchers call for urgent action: better satellite data, improved dust models, and deeper studies of dust’s regional impacts, especially in hotspots like the Arctic or Amazon.

This study is a wake-up call. Dust isn’t just dirt—it’s a climate influencer with a global reach. By overlooking its historical rise, we’ve underestimated its cooling power, which could bias our understanding of climate sensitivity. As we face a warming world, unlocking the secrets of these tiny particles could be key to sharper climate forecasts and smarter strategies to tackle change. The deserts are speaking, and it’s time we listened.

Reference :Kok, J.F., Storelvmo, T., Karydis, V.A. et al. Mineral dust aerosol impacts on global climate and climate change. Nat Rev Earth Environ 4, 71–86 (2023). https://doi.org/10.1038/s43017-022-00379-5