Small volcanic eruptions could cool Earth

Team of scientists say that aerosols that are the minute droplets of sulphuric acid from relatively small volcanic bursts can be shot into the high atmosphere weather systems such as monsoons. 

Volcanoes are both constructive and destructive. But most often it is the destructive aspect of the volcanoes that is being talked off.  However, the new study done by an International team led by University of Saskatchewan claims that small volcanic eruptions have a big impact on global climate.

This team of scientists say that aerosols that are the minute droplets of sulphuric acid from relatively small volcanic bursts can be shot into the high atmosphere weather systems such as monsoons.

Aerosols in the lower atmosphere usually rain back down to Earth right away.

But aerosols at stratosphere can really have an impact on the climate, Bourassa said. Incoming sunlight hits the droplets and scatters, potentially cooling the Earth's surface.

The lead researcher Adam Bourassa, who is with the university's Institute of Space and Atmospheric Studies, said, "If an aerosol is in the lower atmosphere, it's affected by the weather and it precipitates back down right away. Once it reaches the stratosphere, it can persist for years, and with that kind of a sustained lifetime, it can really have a lasting effect."

The researchers analyzed the 1991 massive eruption in Mount Pinatubo in the Phillipines that got a drastic change in the temperatures. The temperatures dropped by half a degree. 

The team, including scientists from Rutgers University in New Jersey, the National Center for Atmospheric Research in Colorado and the University of Wyoming, looked at the June 2011 eruption of the Nabro volcano in Eritrea in northeast Africa. The researchers say, "Wind carried the volcanic gas and aerosol, minute droplets of sulphuric acid  into the path of the annual Asian  summer monsoon."

These dust particles from the Nabro Volcano settled as they were heavier. But the monsoon knocked the volcanic gases and the lighter liquid droplets into the stratosphere. These particles were detected by the Canadian Space Agency OSRIS instrument aboard the Swedish satellite Odin. The Nabro volcano caused the largest stratospheric aerosol load ever recorded by OSIRIS in its more than 10 years of flight.

The research that appears in the July 6 issue of the Journal of Science hopes that the findings will allow more accurate models of climate behaviour and change.