SINGAPORE, Jan. 19 (Xinhua) -- A weather and climate expert said on Tuesday that so far he did not expect a substantial impact on the global environment from the recent volcano eruption in Tonga.
The eruption in Tonga is quite sizable, with dust and gases that came out of the volcano reaching up to 30 km, according to data from NASA sources, said Koh Tieh Yong, associate professor with the School of Science and Technology at the Singapore University of Social Sciences.
"When you inject a substance into 30 km high, it has gone beyond the layer of the troposphere where you have all the weathers going on into the next layer of the atmosphere known as the stratosphere," he said in an interview with Xinhua.
When the gases entered the stratosphere, there are two possible effects of sulfur dioxide and carbon dioxide.
After the sulfur dioxide gases caused by the eruption entered the stratosphere, they would have been converted into sulfur crystals. As sulfur crystals scatter sunlight, hence less sunlight reaches the earth's surface, which theoretically might cool the earth's surface.
The NASA data seems to suggest that up to now, the amount of sulfur dioxide ejected is about 400 million kg, about 50 times less than the very famous volcanic eruptions by the Pinatubo in the Philippines in 1991.
"The Pinatubo eruption brought about 0.6 degrees Celsius of cooling on the earth's surface, and this one in Tonga with 50 times less sulfur dioxide will not have a substantial impact on the global surface," he said.
Secondly, people might worry about the carbon dioxide that is ejected into the atmosphere, because carbon dioxide is a greenhouse gas responsible for global warming.
As the amount of carbon dioxide is also much smaller compared to the amount of which emitted by the industries and transport, the carbon dioxide ejection by this volcano is negligible.
"So one can be assured that not much global impact will be seen," he said. However, local impacts still exist, he noted.
Obviously, winds will carry the dust from the volcano around the world before the dust eventually settles down, particularly in the area around Tonga. The dust would cover the plants and buildings, etc.
That would have an impact on the local environment, but this would occur over one week or two weeks, then it will be over, he said.
"So there are no long-term impacts to the environment, but the volcano would have other effects quite apart from the atmospheric aspect," he pointed out.
It can be possible an eruption can be followed up by smaller eruptions, and it finally depends on altogether how much of the gases and dust are ejected by the volcano, he said.
"Since this event is new and it is hard to say what would happen in the coming days, we still need to keep a watch on it," Koh said. ■
