Studying the past could benefit the future as people learn about it, and then adjust to the same conditions now. As climate change continues, scientists look to the same situations in the past to see how we could cope now. One research turns to Africa, where a reduction of dust in Africa could have changed its climate 11,000 years ago.
The dust in Africa turns out to be important for climate. The trade winds carry mineral dust from Africa to the Atlantic Ocean. The dust helps keep the Atlantic cool as it blocks out sunlight. Around 5,000 to 11,000 years ago there was less dust coming from Africa, however. This has raised the Atlantic Ocean's temperature slightly.
Around that time only half of the dust that is being carried now came from Africa. Researchers from the Massachusetts Institute of Technology and Yale University have said that the Atlantic has temperature rise to 0.15 degrees Celsius. The temperature rise has been enough to increase monsoons in North Africa.
David McGee, the Kerr-McGee Career Development Assistant Professor in MIT's Department of Earth, Atmospheric and Planetary Sciences and co-author of the study, said that even a small fraction of temperature change can have a big impact on wind and precipitation patterns. With a smaller amount of dust coming from Africa, there was more sunlight it some parts of the Atlantic. This has led to changes in weather pattern at that time.
Around that time, the world has just seen the Ice Age end, according to MIT News. Some places like the Sahara were much greener and had a better climate. Regular monsoon rains were part of the climate there. With lesser dust coming from Africa, more monsoon rains came to the region.
Dust is made up of fine grains that could partially block out the sun. Dust is light that it can be carried around for thousands of kilometers before settling down. To study how much dust was carried over then, McGee and his colleagues took sediment samples from the Bahamas collected by the Woods Hole Oceanographic Institution back in the 1980s. By studying the isotope thorium in each layer, the team has known how much dust settled at that time, as Science Daily reports.
Researchers from Yale University made a climate model to see how changes in the amount of dust coming from Africa could affect climate. Through the model, it was shown that a reduction of dust is enough to raise temperatures in the Atlantic by 0.15 degrees Celsius. Lead author of the study is Ross Williams, a graduate student at MIT.
Reduction of dust in Africa could have changed the climate 11,000 years ago. This shows that the environment plays a big role in climate change. Another effect of climate change is that it is hindering the cooling properties of volcanoes.
