A pall of carbon monoxide that hovered over Australia during wildfires there in 2004 came mainly from forest fires in South America, some 13,000 kilometers (8,000 miles) away, the European Space Agency (ESA) said on Wednesday. The discovery was made by scientists evaluating data from ESA's environmental satellite, Envisat, which is equipped with a highly-sensitive instrument for mapping sources of carbon monoxide and other gas pollutants.
Scientists became intrigued when they found a major plume of carbon monoxide over central Australia, a desert region that is not prone to bad wildfires.
"Initially we assumed that the wildfires in North Australia were responsible for this," said Annemieke Gloudemans from SRON Netherlands Institute for Space Research.
"Yet when we took a closer look at the transport of carbon monoxide, we had to conclude that the majority originated from fires in South America.
"Even one-third of the carbon monoxide enhancements in North Australia originated from South America."
The researchers said they were extremely surprised by the finding. Carbon monoxide from forest fires is known to be carried over long distances but is usually detected in dissipated form. The invisible plume travelled eastwards along the southern hemisphere, crossing the South Atlantic, southern Africa and Indian Ocean before petering out in the Pacific.
