‘Robust little’ vessel begins treacherous 22,000km journey around Antarctica in the name of climate science

A small uncrewed vessel has embarked on a lap around Antarctica and may not return for months.

The seven-metre craft, which looks like a large kayak in hi-vis orange, is expected to travel about 22,000km through inhospitable waters, propelled by powerful westerly winds and energy from the sun. The journey is seven times the distance between Sydney and Perth.

Along the way, it is expected to encounter massive waves, freezing temperatures, ferocious winds, and even the odd curious seal or albatross.

The mission? To collect data on carbon dioxide in the ocean and atmosphere, to help scientists better understand the role of ocean sinks.

Dr Elizabeth Shadwick, a principal research scientist at the CSIRO, said that after leaving Hobart the vessel would travel east towards New Zealand, “eventually scooching through the Drake Passage between the bottom of South America and Antarctica, then coming along past South Africa and back to us here, where we’ll pick it up.”

She hoped to see it again in seven to nine months.

The autonomous vehicle made by the US maritime company Saildrone was designed to withstand the intrepid voyage, with a heavy keel keeping it upright, a rudder to steer and a fixed solar sail poking above the surface. It would be remotely monitored by the company, who would check in regularly via satellite, and, if necessary, nudge it in the right direction.

“It’s already been bashed around pretty heavily,” Shadwick said. “It’s quite a robust little device. We saw some eight metres of waves just the day after we deployed it and a 35-knot wind.”

Measurements taken throughout its journey – including wind speed, atmospheric pressure, solar radiation, ocean temperature, salinity and chlorophyll, as well as carbon dioxide levels in the water and air – were expected to assist scientists in better understanding the role that oceans play in global heating.

“The ocean is doing all of us a great service by absorbing about a third of anthropogenic or human emissions every year,” Shadwick said, and the Southern Ocean, around Antarctica, played a significant role. “If we want to continue to rely on this ocean service of absorbing our human emissions, we need to understand how it might change in the future.”

Crewed research vessels that travelled between Hobart and Antarctica traversed only a limited patch of the ocean, she said. The autonomous craft would gather data over a greater distance and time, including crucial measurements during the polar winter.

The vessel is the first in a fleet of four. Others are planned to be launched at three-monthly intervals. They will be spread across the Southern, Pacific, Atlantic and Indian oceans, particularly during winter.

The scientists will be able to access information in near real time via a mission portal, and once the vessels return to home base, all data and observations will undergo quality checks before they are made available for further research.

Dr Pep Canadell, a chief research scientist at the CSIRO, said for every tonne of carbon dioxide released by burning fossil fuels, about 500kg were removed by ocean and forest sinks. “This is like a 50% discount on climate change,” he said.

But the amount absorbed by the oceans could change due to multiple drivers: warming waters, westerly winds, melting ice, ocean acidification and the hole in the ozone layer. Observations would enable scientists to more accurately model these processes and understand how they could change in the future, he said.

The University of New South Wales professor Matthew England, who studies the role of ocean circulation in global climate but was not involved in the research project, said measuring how much the oceans absorbed and how that was changing was critical.

“We’ve obviously got a surge of emissions going into our atmosphere. Both the terrestrial vegetation on land and the oceans absorb a big chunk of that,” he said. “We need to track that carbon uptake and understand exactly how big the absorption is. If it starts to decline in a significant way, then it tells us that we have an even bigger problem of carbon emission reductions.”

The Southern Ocean was “inhospitable” with huge swells, gale force winds, sea ice and storms. “These are very tough measuring conditions for a research vessel.” So gathering data using an autonomous vehicle, without burning fuel, was “an incredible deployment of technology”, he said.