Scientists unveil reason behind drought and heatwave in South America


A new study conducted by an International team of researchers at the Federal University of Santa Catarina in Brazil, Australia's ARC Centre of Excellence for Climate Extremes and NOAA in the US has found that the scorching drought which happened in 2013-2014 was the result of a climate event which happened over the Indian ocean.

The research report published in the journal Nature Geoscience suggested that this is not the first time impacts on the Indian Ocean is bringing extraordinary heat to the South American region.

How did it happen?

It all happened when a strong atmospheric convection over the Indian Ocean triggered a powerful planetary wave. This strong wave traveled across the South Pacific to the South Atlantic, and later it displaced the normal atmospheric circulation in South America. Researchers, in their study report, revealed that these large scale planetary waves are being created when the atmosphere is disturbed.

"The atmospheric wave produced a large area of high pressure, known as a blocking high, that stalled off the east coast of Brazil. The impacts of the drought that followed were immense and prolonged, leading to a tripling of dengue fever cases, water shortages in São Paulo, and reduced coffee production that led to global shortages and worldwide price increases. Highs are associated with good weather. This means clear skies - so more solar energy going into the ocean - and low winds - so less ocean cooling from evaporation," said Dr Regina Rodriguez, the lead author of the study, reports.

The researchers also added that these planetary waves negatively impacted the local fisheries in the region.

To prove that these atmospheric waves are not an isolated event, scientists collected data from 1982 to 2016, and they found that this phenomenon had many times brought drought to South America.

"Using observations from 1982 to 2016, we noticed an increase not only in frequency but also in duration, intensity and area of these marine heatwave events. For instance, on average these events have become 18 days longer, 0.05°C warmer and 7% larger per decade," revealed Andrea Taschetto, co-author of the study.

A few days back, another study funded by NASA revealed that Thwaites, one of the largest glaciers in Antarctica that measures more than 70,000 miles is on the verge of melting. The research report suggested that the melting of this glacier could result in 20-inch global sea level rise within the next 150 years.