Dust in the atmosphere can mitigate the heating effect of trapped greenhouse gases.
If climate science were simple, perhaps we could design a quick fix that would suck out the carbon trapped in the atmosphere, and restore weather to it’s pre-freaky ways. Unfortunately, that’s not how nature works.
To further add to the complexity, The Economist has released a report that in addition to providing nutrients to oceans and forests, dust has cooling qualities. Even that is not simple. Sometimes dust is a good thing, and there is more of it than previously, but then sometimes it can set off an unhappy chain of reactions.
The magazine describes an incident in May, 2008, when Sahara sands traveled to Europe and “turned Germany red”; subsequent research by Max Bangert, a Karlsruhe Institute of Technology student, demonstrates that while the dust hovered in the atmosphere above Germany, the ground below cooled by 1/4 of a degree.
Dust from hot dry (and sandy) regions regularly travels thousands of kilometers, influencing weather patterns and even transporting nutrients such as iron and phosphorous. The Amazon forest receives phosphorous from Africa, which in turns stimulates plant growth that sponges up carbon.
Ilan Koren and colleagues from Israel’s Weizmann Institute of Science have tracked dust by satellite from the Bodélé Depression, considered one of the dustiest places on the planet, as it traveled from Chad to Nigeria, across the Atlantic, and landing finally in Manaus, Brazil.
Dust in the atmosphere deflects sunlight back into space, offsetting some of the heat that accumulated greenhouse gases trap. Of the additional 1.6 watts of extra solar power heating each square mile of the planet, dust can offset 0.14 watts.
In some cases, this cooling has negative effects. By changing airflow patterns, the dust can indirectly cause less rainfall that in turn causes plants to die, and makes them more vulnerable to wildfire. These natural events are responsible for enormous bursts of carbon emissions.
Research from Cornell University shows that there is at least twice as much dust in the atmosphere than in the previous century, which may result from human activity such as land clearing, or even global warming, which may alter the boundaries of deserts. Jasper Kok of the National Centre for Atmospheric Research, on the other hand, believes that there may be as much as eight times as much dust in our atmosphere than there was before.
While no direct conclusions can be drawn, the story of dust demonstrates the full complexity of climate science, and the numerous factors that have to be considered when making predictions.
In fact, it may be impossible to make true predictions.
More on dust and desert in the Middle East:
Martian Technology That Zaps Dust From Solar Panels
Dust Swept Into Arabian Gulf Delivers Key Nutrients
Israeli and Jordan Desert Plant That Waters Itself
image via gilliu00
