Shared from the 8/22/2021 The Age Digital Edition eEdition

Scientists turn to risky plan B as the world fails on climate change

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A plan to release a balloon into the stratosphere to test a tecnological fix for climate change was abandoned.

Photo: Swedish Space Corporation

In June this year Harvard scientists had planned to release a balloon from Esrange Space Centre in northern Sweden and, once it had climbed into the stratosphere, release a small vial of calcium carbonate, the sort of substance you’d normally come across in a dose of antacid. The balloon never took off. The scientists, whose experiments were to have informed the development of new technologies that might rapidly cool the Earth by reflecting heat from the sun back into space, bowed to protests from activists appalled by the implications of their work. Some fear a future world addicted to an unnatural method of regulating the climate and the potential of terrible unintended consequences. Some even fear living under a sky whose hue is artificially whitened. Despite such fears, in the wake of the UN report published last Monday showing that even if the world quickly and massively reduces emissions we are still likely to see warming of 1.5 degrees in the coming two decades, some attention is returning to controversial technological climate fixes, particularly in the field known as solar geoengineering.

Simon Nicholson, an associate professor of international relations at American University who specialises in laws governing emerging environmental technologies, says he believes the report will help overcome the taboo around that research.

In its simplest terms, the process the Harvard team are researching may one day involve flights of specialist aircraft regularly dumping powder into the stratosphere, where it would linger for months reflecting a portion of inbound sunlight. Types of solar geoengineering have proven attractive to researchers because they appear to be physically and economically viable and rapidly scalable.

We know for example, that when Mount Pinatubo in the Philippines exploded in volcanic eruption in 1991, it cooled the planet by 0.6 degrees for about 15 months due to the particulate matter it disgorged into the atmosphere.

Modelling suggests it would cost billions of dollars to mimic that effect

– yet that is small change compared with the sums typically bandied about in climate debates.

The arguments against the process are compelling too.

Nicholson notes that many of those engaged in the climate movement want to educate humans to live within natural limitations. ‘‘Anything that seems to smack of the type of hubris that got us into this mess in the first place, like heavily industrial, highly capitalist types of pathways forward, tend to be viewed sceptically.’’

A second concern is the ‘‘moral hazard’’ such technologies may present by diverting research from efforts to curb emissions and present industry with a continued licence to pollute the planet.

Michael Mann, one of the world’s leading climate scientists and communicators, and Oxford physicist Ray Pierrehumbert, likened the process to ‘‘climate methadone’’ in a recent column in The Guardian newspaper.

‘‘When it comes to a system we don’t understand perfectly, the principle of unintended consequences reigns supreme,’’ wrote Mann in his recent book The New Climate War. ‘‘If we screw up the planet with botched geoengineering attempts, there is no ‘do-over’.’’

Nicholson believes the new climate report suggests we no longer have the luxury of not investigating geoengineering. ‘‘We’re in a position now where it’s not just the risks of solar geoengineering versus a world where climate change has been dealt with in other ways,’’ he says.

‘‘That’s not what the [Intergovernmental Panel on Climate Change] report is putting on the table for us. Instead what the IPCC is saying is climate risk is going to get worse moving forward, even if we do everything that the IPCC is recommending to reduce emissions.

‘‘I think we may reach a point down the road where solar geoengineering is going to be one of the most just things that can be done to help those who are most vulnerable to climate change.’’

In March this year, before the Harvard team abandoned its test flight, Dr Dan Harrison of Southern Cross University led a team of scientists on a live-aboard barge onto a section of the Great Barrier Reef off the coast of Townsville to test specialised new equipment that might one day help cool the reef and avert coral bleaching.

Harrison’s team is exploring a process known as cloud brightening, technically a form of solar geoengineering, though on a far smaller and less controversial scale.

It involves blasting seawater high into the air using specialised pumps and nozzles to create a mist of ultrafine particles. Once airborne the droplets evaporate, leaving behind billions of salt crystals that can form the nuclei of cloud droplets.

These in turn would make clouds brighter and more dense, cooling the reef below by reflecting more of the sun’s rays and through evaporation.

Harrison’s hope is that one day equipment like this could be moored at key points along the reef and deployed on what he calls ‘‘ships of opportunity’’ – vessels that already ply the reef, as well as carefully placed barges.

As with the Harvard team’s stratospheric aerosol injection, cloud brightening has already been observed in the field by chance, caused by the wakes of ships.

So far, he says, the group’s two field trials suggest it could work.

Harrison doubts a process like this is viable to cool the Earth, but the team’s results suggest it may help to protect the reef. ‘‘I view it as life support or something, treating the symptoms while hopefully the cause is taken care of,’’ he says.

‘‘Emissions reductions to reduce climate change aren’t going to happen quickly enough to save the reef, which is why we have this whole program now.’’

Harrison believes the argument that such technologies might distract from efforts to combat climate change by emissions reduction is ‘‘nonsense’’: ‘‘We haven’t had these geoengineering solutions to hand with any real chance of working or any proof of their efficacy, and yet we’ve done very little to reduce our carbon emissions or change the trajectory of climate change.

‘‘It’s now a risk versus risk equation,’’ he says. ‘‘The question of whether we should implement any of these ideas is one for wider society, but the scientists need to do the research to be able to provide the right information to allow that debate to occur.

‘‘You need knowledge as a foundation, instead of speculation.’’

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