Study concludes African weather affects Caribbean


A recent study conducted by National Oceanic and Atmospheric Administration
(NOAA) Joint Institute researchers concluded weather on one continent can affect other parts of the world and result in significant impacts ranging from climate change to public health.

A key result of the study, published in today’s issue of Science, is that trade wind dust transport from West Africa to Barbados in the eastern Caribbean is strongly linked to rainfall in West Africa. Decreased rainfall in Africa results in a sharp increase in dust transport across the Atlantic the following year. The paper discusses the climate change and health implications of the results for the Caribbean and southeastern United States.

Great quantities of atmospheric dust are carried by the trade winds from Africa over large areas of the North Atlantic and to the Caribbean during much of the year. Measurements from 1965 to 1998 in Barbados show large interannual changes in dust amounts. The researchers compared the dust amounts with African rainfall data, and found a strong relationship between the dust and the previous year’s rainfall. Using this relationship, the researchers then were able to reconstruct the dust transport for 1941-64 from long-term rainfall data.

The study found that dust concentrations were sharply lower during much of the 20th century before 1970, when rainfall across the Soudano-Sahel region was more normal, and when it was especially wet during the 1950s and early
1960s. Since 1970, the region has suffered varying degrees of drought, which has caused the amount of dust to increase. The amount of dust transported from Africa could affect south Florida by suppressing rainfall and worsening droughts.

Because of the sensitivity of dust emissions to climate, future changes in climate could result in significant changes in emissions from African and other arid regions that, in turn, could lead to impacts in climate over large areas.

The study’s findings have implications for climate, atmospheric quality and public health in the Caribbean and south Florida. The results demonstrate how climate processes can bring about changes in our environment that could have a wide range of consequences on intercontinental scales.

The research was supported by grants from the National Science Foundation, National Aeronautics and Space Administration and the NOAA Office of Global Programs.

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