Autonomous Vessel Begins 22,000km Antarctic Voyage to Study Ocean Carbon

After leaving Hobart, the vessel is expected to travel east towards New Zealand, pass through the Drake Passage between South America and Antarctica, continue past South Africa and return to Australia, said Dr Elizabeth Shadwick, a principal research scientist at CSIRO. She said she hoped to see it again in seven to nine months.

Made by US maritime company Saildrone, the craft looks like a large kayak in high-visibility orange. It is propelled by powerful westerly winds and energy from the sun. It has a heavy keel to keep it upright, a rudder to steer and a fixed solar sail above the surface. Saildrone will monitor it remotely and check in via satellite, nudging it in the right direction if necessary.

The distance is seven times that between Sydney and Perth. Along the way, it is expected to encounter massive waves, freezing temperatures, ferocious winds and the odd curious seal or albatross. “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.”

Throughout its journey, the vessel is to measure wind speed, atmospheric pressure, solar radiation, ocean temperature, salinity and chlorophyll, as well as carbon dioxide levels in the water and air. The data are expected to help scientists better understand the role oceans play in global heating. Shadwick said the ocean absorbs about a third of anthropogenic, or human, emissions every year, and the Southern Ocean around Antarctica plays 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 travelling between Hobart and Antarctica cover only a limited patch of ocean, Shadwick said. The autonomous craft is expected to 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 for launch at three-month intervals and will be spread across the Southern, Pacific, Atlantic and Indian oceans, particularly during winter. Scientists will be able to access information in near real time through a mission portal, and after the vessels return all data and observations will undergo quality checks before being made available for further research.

Dr Pep Canadell, a chief research scientist at CSIRO, said about 500kg of every tonne of carbon dioxide released by burning fossil fuels is 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 because of warming waters, westerly winds, melting ice, ocean acidification and the hole in the ozone layer. He said observations would allow scientists to model these processes more accurately and understand how they could change in the future.

Matthew England, a University of New South Wales professor who studies the role of ocean circulation in global climate and was not involved in the research project, said measuring how much the oceans absorb and how that is changing is 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.” He called the Southern Ocean inhospitable, with huge swells, gale-force winds, sea ice and storms, and said gathering data with an autonomous vehicle without burning fuel was an incredible deployment of technology.