Saharan dust and climate justice

The silent invasion of Saharan dust

Have you ever wondered what it would feel like to stop seeing a horizon that was once so familiar? Or that your eyes are no longer graced by the peaks that shelter you within what, day after day, you call your home?

One day, those mountains that have been an indelible part of my life since the twilight of my childhood completely disappeared, and I even came to question whether that horizon was real, or a fragment of nostalgia.

On July 19, 2023, I woke up with a strange sensation in my throat and wondered: was it allergic rhinitis, COVID-19, or the flu? When I took a test and it came out negative, I thought the summer flu was going to be responsible, until I read the news. That day, the usual cloud of dust from the Sahara arrived in the country, except that its presence dwarfed our small island state – that desert-colored nimbus was forty times larger than the Dominican Republic, and although its impact did not resemble the catastrophes occurring in Algeria, China, Japan, Morocco, Italy, Greece and other countries facing record temperatures, the subtle invasion of these supposedly innocent particles gives us a chronicle of misfortune told in the form of analogy: allergies , respiratory diseases, affected eyes, exacerbation of heat and concentration of greenhouse gases.

The horizon disappeared, and I realized that everything had changed.

The silent invasion of Saharan dust
The silent invasion of Saharan dust

Every year, more than 100 million tons of particles from the largest desert in the world travel distances greater than 10,000 kilometers, covering the skies in the neighboring continent of Europe, and even reaching as far as the southeastern coast of Mexico. This makes the Sahara Desert the main source of the dust that covers our planet, especially between the months of June and August. This concentration of dust occurs at the end of spring and moves through the Atlantic Ocean every three to five days, settling in the atmosphere in clouds between 3 and 5 kilometers thick and at a height of between one and two kilometers in the atmosphere, before to spread after no more than a week.

It is important to highlight that this is not a recent phenomenon. According to National Geographic, this event brings benefits to the Amazon rainforest and marine phytoplankton in the form of minerals such as phosphorus and iron, nutrients they need to develop. In the case of the Amazon, its biological wealth can be considered miraculous when we take into account that its soil lacks fundamental minerals, specifically phosphorus, to maintain a suitable ecological balance. This occurs as a result of the rains that constantly wash away the different layers of the soil, and that is where the dust from the Sahara comes in to compensate for this deficit.

This dynamic is even more impressive when we consider the findings of a 2014 study, titled: ” Quantifying the Sources of Dissolved Iron in the North Atlantic Ocean” (Conway and John), which found that this dust contributes more than 70% of the iron that the photosynthesizers of the Atlantic Ocean require to develop.

Another benefit of these dust clouds brought by the trade winds is the suppression of the formation and strengthening of hydrometeorological phenomena commonly observed in our region. These dry dusty layers collide with moisture-dependent storms, which are extinguished before causing any significant damage to ecosystems.

However, climate change caused by anthropogenic activity has negatively exacerbated the harmony that our planet has maintained for millions of years. According to atmospheric chemist Olga Mayol, from the Institute of Tropical Ecosystem Studies at the University of Puerto Rico, the formations of the last fifty years have had higher concentrations of dust particles that stay at lower altitudes, exposing a greater amount of people to its components, which include remnants of pollutants resulting from deforestation in sub-Saharan countries.

When staying at a closer distance from where people carry out their daily lives, the frequency with which many people, even those without a medical history of respiratory diseases, report allergic episodes and asthma attacks becomes worrying . This, combined with the symptomatic picture of COVID-19, exposes a greater number of individuals to health complications caused by the unusual amount of allergens, viruses, bacteria and harmful substances, including iron pesticides and silica, present in the air covered by the dust of the Sahara .

In 2020, Sam Heft-Neal, Eran Bendavid, Marshall Burke, Jennifer Burney, and Kara K. Voss (Sam Heft-Neal et al) published an article in the scientific journal titled: “ Saharan Dust Pollution and Infant Mortality in Africa “ In this study, Heft-Neal and a team of four scientists examined records from the last 15 years on the air quality of the community of Bodèle, in Chad, which is noted for being one of the world’s main sources of dust, containing so many particles that residents sometimes find it difficult to breathe. The conclusion? “The density of dust in the air was closely related to whether a newborn baby could survive a year.” In West Africa, Heft-Neal et al found that if this dust made up 25% of the air breathed, the baby’s chance of survival decreased by 18%.

In the Caribbean context, this reality is more harmful when taking into account that this cloud of dust from the Sahara contains 50% less humidity than the air we are used to inhaling.

So, what relationship exists between this atmospheric phenomenon and climate change ? It is not recent knowledge that the communities most affected by climate change are those that contribute the least to it. Even the link between these anthropologically provoked transformations and health is an area of ​​study that is closely related to debates about climate justice.

For example, the excess nutrients brought by clouds in the last 3-4 years have had an impact on the growth of algae such as sargassum, one of the most urgent regional challenges facing the Caribbean. According to Natalie Mahowald, a climatologist at Cornell University in the United States, “it is likely that almost half of the increase [in dust clouds] is due to climate change and that the other half is influenced by changes in land use.” of soil in the Sahara, as agricultural and human pressures have increased.”

Part of what’s fascinating and intimidating about studying dust is the uncertainty about its role in the future of climate change , as Mahowald puts it: “Sometimes dust creates reflective clouds that can deflect heat.” additional, but other times it creates clouds that trap heat near the Earth’s surface.” For example, when dust is over the sea, it can reflect the sun’s heat and cool the planet. On the other hand, if it is transferred to reflective surfaces such as ice or snow, it has the opposite effect and accelerates the melting process of the latter.

Regarding the previously mentioned photosynthesizers, she observes that, in extreme quantities, the fertilization capacity of the dust is so strong that it could have caused the massive growth of living beings that extract carbon dioxide from the atmosphere, which could have caused ” “at least a quarter of the change in atmospheric CO2 that led the planet into the last ice age.”

Many of the natural phenomena we observe today are unimaginable versions of what our planet does to maintain a perfectly balanced microcosm. However, given the relatively recent nature of the negative effects of this dust, it is important to study it in conjunction with the public health area . If we truly want climate justice for the Caribbean and the rest of the world, it is necessary to recognize the connections that exist between the constantly evolving dynamics of our planet and the transformations we impose on it. We cannot talk about climate change without addressing health , and we cannot talk about the growing wave of respiratory and autoimmune diseases without first recognizing that we are all responsible for this chain of events. Although the Dominican Republic has a significantly lower degree of responsibility for the actions that led us to where we are, that does not nullify the commitment it has to its citizens around the world. We may not have been part of the problem, but if I have observed anything in recent years, it is that every day more people join in and say: “I will be part of the solution.”


This story was published on Diario Libre with the support of the Caribbean Climate Justice Journalism Fellowship, which is a joint venture between Climate Tracker and Open Society Foundations.

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Gabriela Taveras Ruiz

Gabriela Taveras Ruiz

Gabriela is a young professional who is skilled in advocacy, research and climate change. She holds a Graduate Certificate in Tropical Forest Landscapes from Yale University, a Master of Arts in Development Studies (majoring in the Environment, Resources and Sustainability) from the Graduate Institute in Geneva, Switzerland, and a Bachelor of Science in Diplomacy and International Relations from Seton Hall University. She grew up in the Dominican Republic and has worked for institutions such as the United Nations, the United Kingdom’s Foreign, Commonwealth and Development Office and the U.S State Department.

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