Tonga’s volcanic eruption may harm environment for years

The destruction from Tonga’s massive underwater volcanic eruption is still being assessed but scientists now warn that the damage could be long-lasting.

The volcano has been releasing sulfur dioxide and nitrogen oxide— two gases that create acid rain.

This could damage crops, including staples like taro, corn and bananas which locals depend on.

Geologist Marco Brenna has been studying the eruption's impact via satellite photos.

"So as the plume rose beyond 20 kilometres it reached well into the stratosphere. So a lot of that ash and gas will remain within the stratosphere for quite a number of weeks and possibly months, and kind of circulate across the globe. The more immediate impact on Tonga especially was the ashfall directly from the cloud which blanketed most of the Tongan landscape in a few centimetres of ash from what has been seen off satellite images. And that basically had an impact on basically water, drinking water sources, on vegetation, grazing for animals etc. because the volcanic ash is toxic."

And it may not just be Tonga - much of the rain could land on Fiji.

Underwater, fish are at risk.

Tonga's livelihoods depend on the ocean..but ash from the eruption could be harmful to marine life.

Murky, ash-filled water near the volcano will deprive fish of food and wipe out spawning beds.

"Certainly fisheries are likely to have been impacted by, for instance, the murkiness of the water. So the eruption would have produced quite a lot of suspended particle in the ocean water, so that might impact fishing grounds. Ashfall could also have such an impact and could potentially cause changes in ocean surface acidification."

Meanwhile, surviving marine life will be forced to migrate.

Even before the eruption, Tonga’s reefs were threatened by disease outbreaks and the effects of climate change including coral bleaching and increasingly strong cyclones.