Read more<\/p>
Want the full picture? Explore our\u00a0geoengineering hub<\/a>\u00a0to read more about this topic.<\/p><\/div><\/div>\n\n\n\n Harrison and his team were there to test a radical intervention that, if successful, could spare the world\u2019s largest coral reef from total loss. Known as marine cloud brightening, their approach involves spraying seawater into the air to help form bright clouds that reflect sunlight and cool the waters below. \u201cThis is like putting the reef on life support while we deal with the underlying cause. It buys us some time\u201d says Harrison. \u201cObviously bringing emissions down is the critical thing.\u201d<\/p>\n\n\n\n While Harrison\u2019s project is small in scale, and in its infancy, marine cloud brightening is just one of numerous practices \u2013 collectively known as geoengineering or climate intervention \u2013 that could cool the planet, offsetting some of the harm caused by greenhouse gas pollution. With global emissions rising, there\u2019s a growing awareness that we\u2019ll likely need such radical measures to avoid dangerous climate change. \u201cEmissions reductions alone are not going to cut it,\u201d says Phillip Boyd, a marine biogeochemist at the University of Tasmania, Hobart. \u201cWe\u2019ve got an increasingly fast-moving problem, and so we may need increasingly fast-moving countermeasures,\u201d says Kelly Wanser, founder of US non-profit Silver Lining, which advocates for research into climate intervention.<\/p>\n\n\n\n Using technology to control the climate is undeniably controversial, seen by some as a quick fix with unknown consequences that diverts attention from the harder task of transitioning to a zero-carbon economy. As such, there\u2019s been little funding for research, and few real-world trials. Harrison\u2019s project \u2013 focused on curbing a national ecological disaster \u2013 is a notable exception. \u201cIt\u2019s essential to know whether these things work or not,\u201d says Harrison. \u201cIf we find out that they don\u2019t work, it just strengthens the argument for reducing emissions harder and quicker and not delaying\u201d.<\/p>\n\n\n\n Geoengineering \u2013 or deliberate climate control \u2013 is not new. During the Cold War, both the US and the Soviet Union funded research into cloud seeding, an approach the US eventually used during the Vietnam war to extend the monsoon season and disrupt enemy troops. Since then, the field has expanded into a wide array of schemes mostly intended to mitigate climate change, though some have co-benefits such as boosting fisheries.<\/p>\n\n\n\n Broadly speaking, there are two approaches. The first, Solar Radiation Management (SRM), aims to limit the amount of heat absorbed by the Earth and could be used to quickly cool the surface. This could be achieved, for instance, by sending reflective sulphates into the stratosphere via giant balloons, or by scattering silica beads over Arctic sea ice to make it more reflective.<\/p>\n\n\n\n The alternative, Carbon Dioxide Removal (CDR), focuses on physically extracting CO2 from the atmosphere and storing it, in ecosystems such as mangroves or forests, underground or in the deep ocean. Possibilities here include fertilising the sea surface with iron to promote the growth of plankton \u2013 which absorb CO2 from the air \u2013 or burning biomass as a source of energy, capturing the CO2 and storing it. So far, no single scheme has been proven to work at scale. Most research has focused on land-based solutions, but competing needs, such as ensuring food security, makes these impractical as global solutions. Scientists are now looking to the open ocean as a more pragmatic choice for geoengineering. \u201cThis is where it makes most sense, because there\u2019s no conflict of interest with any other issues. These areas are largely unused at the moment and they also make up 50% of the planet\u2019s surface\u201d says Ulf Riebesell, a biological oceanographer at the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany.<\/p>\n\n\n\n So far, 27 different marine geoengineering schemes have been proposed. There has been roughly a dozen field tests, mostly focused on ocean iron fertilisation. When a commercial company, Planktos Inc, proposed to test the technology off the Galapagos Islands in 2007, it sparked fears of unregulated interference with the planet\u2019s climate by entrepreneurs looking to turn a quick profit by selling sequestered CO2 as carbon credits.<\/p>\n\n\n\n In response, two intergovernmental bodies sought to outlaw geoengineering. In 2010, the UN\u2019s Convention on Biological Diversity recommended that member states ban the deployment of all large-scale climate intervention technologies, a stance that it reaffirmed in 2016. Meanwhile, in 2013, the UN\u2019s International Maritime Organization (IMO) \u2013 which regulates shipping \u2013 added ocean iron fertilisation to its list of banned practices. Though the IMO measure is voluntary and yet to be enforced, it symbolises the taboo long associated with climate intervention.<\/p>\n\n\n\n With global emissions still growing despite the commitments made in Paris in December 2015, the mood has started to shift. The Intergovernmental Panel on Climate Change has made it clear<\/a> that we have little chance<\/a> of avoiding dangerous levels of warming, generally regarded as 1.5C or 2C above pre-industrial temperatures, without geoengineering technologies. Meanwhile, high level organisations such as the UN Environment Programme and the US National Academies of Sciences have started to seriously evaluate options for climate intervention.<\/p>\n\n\n\n \u201cWe\u2019re now in a situation where we\u2019re implicitly assuming that we\u2019ll need large-scale CO2 removal, but we really haven\u2019t put the time and money into actually finding out whether we can do it or not\u201d, says Jeffrey McGee, director of the Australian Forum for Climate Intervention Governance at the University of Tasmania, Hobart. \u201cThe gap between expectations and knowledge, I think, is getting wider and wider by the day.\u201d<\/p>\n\n\n\n Globally, just a few marine geoengineering projects are ready for field trials. Ocean artUp, being led by Ulf Riebesell, is testing the idea that artificial ocean upwelling \u2013 using vertical pumps \u2013 can enrich the ocean\u2019s nutrient-poor subtropical gyres, boosting fish production and CO2 uptake. Riebesell\u2019s team is currently testing various pump designs in waters off the north Atlantic island of Gran Canaria.<\/p>\n\n\n\n Arctic Ice Project, an initiative started by Leslie Ann-Field, a lecturer at Stanford University in California, aims to prove that it\u2019s possible to use technology to restore Arctic ice. Field\u2019s method involves scattering tiny glass silica beads on the surface of thin, young Arctic sea ice as a way of boosting its reflectivity by 50%. Field\u2019s team was due to test the method on a small scale at Utqiagvik, Alaska this summer but plans have been scaled back owing to Covid. Follow-on plans to test the method in the Arctic at a larger scale will need additional funding.<\/p>\n\n\n\n Meanwhile, the Marine Cloud Brightening Research Program, a collaboration between the University of Washington, the Pacific Northwest National Laboratory, and a team of retired engineers in Silicon Valley, has emerged as the sole significant US effort in marine geoengineering. With limited funding, the team has designed a bespoke nozzle that can generate three trillion particles of tiny salt particles per second from filtered sea water. The next step, developing this into a system of 400-500 nozzles that can be tested in the field, will need roughly $4-5 million, which the research team is currently raising.<\/p>\n\n\n\n The consequences of deploying any of these technologies at scale is unknown. Already, the ocean has soaked up one third of the roughly 40 billion tonnes of CO2 that we emit annually, as well as 93% of the extra heat from climate change. While this has tempered climate change on land, it has caused the ocean to warm rapidly and become more acidic. Conservationists worry that marine geoengineering could harm marine life, or the health of the ocean.<\/p>\n\n\n\n \u201cGeoengineering is not only complex and unknown, but it has huge potential impact,\u201d says Torsten Thiele, founder of the Global Ocean Trust, a non-profit that focuses on marine conservation, technology and governance. \u201cI\u2019m very sceptical on letting people try things out until we\u2019ve sorted out the other steps and processes. Let\u2019s first figure out the framework, let\u2019s figure out the ethics standards, let\u2019s figure out what happens in the lab. We could create a long list of things that would allow natural scientists to improve knowledge without actually trying these things out in nature.\u201d<\/p>\n\n\n\n With field trials inching forward, attention is turning to how geoengineering research \u2013 and deployment, if it ever happens \u2013 should be governed. Right now, different laws could be applied to geoengineering on land and in the ocean, but none are comprehensive. The IMO amendment on ocean iron fertilisation, for instance, just applies to a single method and then only if the iron is \u201cdumped\u201d at sea, rather than piped or injected, for instance. \u201cWhat we have right now is a patchwork of rules\u201d says Kerryn Brent, who researches international environmental law at the University of Adelaide, Australia.<\/p>\n\n\n\n One possibility for governing marine geoengineering is through a new law to protect marine life on the high seas<\/a>, those waters that are beyond national governance. The law, which is currently being negotiated by the UN, will likely require any activity that takes place on the open ocean to first undertake an environmental impact assessment, a formal process to gauge potential damage to marine life.<\/p>\n\n\n\nClimate intervention<\/h2>\n\n\n\n
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In general, SRM is seen as the more extreme approach that could be deployed with quick results in the case of a regional or global climate emergency.<\/p>\n\n\n\n![](\"https:\/\/dialogue.earth\/content\/uploads\/2020\/08\/GSFC_20171208_Archive_e001969_orig-scaled.jpg\")
<\/div>Growing expectations for unproven technologies<\/h2>\n\n\n\n
There’s not much time to decide which of these options is useful. We shouldn\u2019t wait another year. The science needs to start now.<\/blockquote>Ulf Riebesell, Ocean artUp principal investigator<\/cite><\/div><\/div>\n\n\n\n
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<\/div>Governance gap<\/h2>\n\n\n\n