This is the latest piece in a series on the COP26 climate summit and the danger Asia faces from global heating. Previous articles can be viewed here.

TOKYO / JAKARTA / BANGKOK / SHANGHAI -- The mass bleaching of Great Barrier Reef coral by rising global temperatures has driven scientists to pioneer a striking new defense: reconfiguring clouds to better block the sun.

Researchers have used a turbine mounted on the back of boat to shoot plumes of seawater over the ocean's surface. The briny spray evaporates and the salty residue drifts into existing low-lying cloud, where it seeds the formation of tiny water droplets. This buttresses the cloud's ability to scatter shortwave solar radiation - and so stops more rays reaching and heating the coral sea below.

"The reef out there is getting hammered," said Daniel Harrison, an oceanographer and senior lecturer at Southern Cross University, in a crisp explanation of why he saw this extraordinary action first trialled off Australia's northeastern coast last year as necessary.

Harrison has led field tests of a technique known as marine cloud brightening. His work is part of a wider contentious effort across the Asia Pacific to counter climate change by artificially altering the environment. Other examples of so-called "geoengineering" include modifying rainfall and removing carbon dioxide from the atmosphere.

Geoengineering is gaining popularity among some scientists and policymakers, many of whom have come to an alarming conclusion. They argue that the only way to prevent the most severe impacts of global warming will be to suck massive amounts of carbon dioxide out of the atmosphere, or to cool the planet artificially. We may even need to do both, they say.

But many researchers and international environmental organizations remain sceptical about whether geoengineering has a big role to play in the battle against global heating. They pose a fundamental question: whether governments and companies will use the mitigating effects of the new technologies as an excuse to avoid slashing planet-warming emissions.

"Australia is one of the countries with a huge contribution to the climate crisis that is running away from its responsibility," argued Dipti Bhatnagar, program coordinator at Amsterdam-based environmental nonprofit Friends of the Earth International.

Eureka moment - or excuse?

The world's geoengineering pioneers insist they could yet be an important part of a solution to the climate crisis, as global greenhouse gas levels and temperatures continue their remorseless climb. While cutting carbon emissions is vital to prevent further damage to the ecosystem, adaptation measures such as cloud brightening should also be used because "we've left it too late," said Harrison, the Great Barrier Reef defender.

Scientists and world leaders have said humanity needs to limit global warming to 1.5 degrees Celsius above pre-Industrial Revolution temperatures. The world has already gone more than two-thirds of the way to that unwanted landmark.

Geoengineering's promoters cast it as a potentially important way to mitigate this catastrophic trend. The UN's Intergovernmental Panel on Climate Change defines geoengineering as "a broad set of methods and technologies operating on a large scale that aim to deliberately alter the climate system in order to alleviate the impacts of climate change."

These techniques are often divided into two broad categories. One is solar radiation management, which aims to temporarily cool the Earth by reflecting sunlight back into space. The other is carbon dioxide removal, which is the physical sequestration of the greenhouse gas from the atmosphere.

Harrison's Great Barrier Reef cloud brightening project remains in early-stage trials, with a small team and a modest budget of roughly $300,000 for the first trial in 2020. But the first test proved that it was possible to produce the seawater droplets in sufficient quantities using artificial mist generation.

His laboratory is the planet's largest reef system. The Great Barrier Reef was nearly listed as an endangered World Heritage Site by the United Nations earlier this year. But Australia managed to dodge the designation - and the protection responsibilities that would come with it - through intense lobbying.

Harrison said his equipment might need to be scaled up by a factor of 10 -- from 320 to around 3,000 nozzles -- to produce enough particles to brighten nearby clouds by around 30%. His team's modeling suggests that this would in turn reduce the incoming solar radiation on the reef locally by around 6.5% over a period of about two months during the summer.

Even then, the operation might require up to 800 to 1,000 stations to cover the 2,300 kilometers of the Great Barrier Reef. But this will take time, with Harrison saying a full trial deployment could take about 10 more years.

His cloud-brightening technique also still has its doubters. Masahiro Sugiyama, associate professor at the University of Tokyo, is among those who call for more research on the effectiveness and potential impact of cloud brightening.

Sugiyama said he was not against geoengineering, but believed it riskier to target one place than to cool down the entire planet. "Atmospheric flow changes when you cool down one location - and we don't know what negative impact it could have," he said.

Fires and floods

Despite skepticism, demand for cloud-altering projects is growing elsewhere in Asia. Authorities view it as a potential weapon against forest fires and floods. It can also help generate hydropower, according to Dwipa Wirawan of Indonesia's National Research and Innovation Agency (BRIN).

Traditionally, colder-climate cloud seeding injects silver iodide or a similar substance into the atmosphere to mimic ice nuclei. This makes the clouds generate more ice crystals that either fall as snowflakes or melt to produce raindrops, depending on the temperature.

In tropical nations such as Indonesia, warm clouds dominate and so a different technique is required. Sodium chloride -- common salt -- is commonly used as the seed for large water droplets. When these fall, they collide with smaller droplets on the way to earth and further accelerate rainfall. In recent years, the country has been using pyrotechnic flares to shoot seeding chemicals directly into the clouds.

Wirawan and his 60 fellow geoengineers at BRIN's weather modification department have been busy this year, flying from one region to another. Fire prevention across parts of Sumatra and Borneo dominated the department's work activity between March and September. Earlier this year, Indonesia used cloud seeding to lessen the severity of floods around greater Jakarta by inducing early rainfall from clouds before they approached the nation's capital.

The operation, which ran from February to March, slashed precipitation in greater Jakarta to 112.8 millimeters, from 188 millimeters in the 10 days prior. The level even dipped below the average of 114.2 millimeters in the same period through the last ten years, according to data from BRIN.

Conversely, cloud seeding was used to prevent fires in the province of South Kalimantan from March to April this year. It generated 186.4 millimeters of rainfall in the province -- more than 50% higher than the previous month and 17% up on the average during the same period from 2011-20.

More recently, Wirawan set up a temporary office near Lake Toba, the world's largest volcanic crater lake. The body of water on the Indonesian island of Sumatra has seen its volume shrink because of drier weather this year. That jeopardized the work of a nearby big hydropower plant, as well as the livelihoods of local fishermen and farmers.

Each cloud seeding operation usually takes around 30 days and costs more than $10,000 per day, according to Wirawan. If they find the right kind of clouds, there's an "80% chance that rains can,"appen", he said. "So if we seed the clouds in the morning, rain will fall in the afternoon and then through chain reactions will also fall later in the evening."

Overall, cloud-seeding has increased rainfall by 20 to 30% in operations for electricity and irrigation in lakes and dams, according to Sutrisno, services coordinator for weather modification at BRIN. Sutrisno said BRIN is seeking to make its weather modification technology still "more effective and efficient," by improving seed materials and methods, modeling and rain forecasting.

Royal rains

Indonesia first learned of cloud seeding from Thailand. The South-East Asian Kingdom's extensive use of the technology in agriculture inspired the Indonesian president Suharto back in the 1970s. Thailand had been working on artificial rain, backed by King Bhumibol Adulyadej, as early as 1969.

Already the world's second large exporter of sugar, Thailand is aspiring to become the "kitchen of the world." It is a big producer of grain, palm oil, corn, fish, beef and chicken.

Artificial rains in Thailand are seen by authorities as key in preventing crop damage caused by abnormal weather patterns. The nation's agricultural sector accounts for roughly 10% of its gross domestic product. That means water is essential to the livelihoods of about 8 million families.

The Department of Royal Rainmaking and Agricultural Aviation has made weather modification a priority, ramping up the budget for it by 30% over the past five years. It plans to set up seven "rainmaking centers" by next year as a step toward eliminating water shortages in nearly all drought-affected areas by 2037.

This year, authorities operated more than 4,000 cloud-seeding flights from February, when Thailand enters its dry season, through October. Rain fell in 64 of the nation's 76 provinces over a period of 221 days, equating to a success rate of 80%, the department said.

"We have been working with several scientific institutes both in Thailand and abroad to get better techniques to apply for Thailand in the future," Wassana Wongrat, director of the rainmaking department's Technology Research and Development division, told Nikkei Asia.

Carbon in caverns

The growing focus on retrieving carbon already released into the atmosphere is a sign of how out of control emissions still are. The most cutting-edge technology, known as direct air capture (DAC), is still in its infancy - and seen by some as a last resort strategy for an ailing planet.

The idea behind DAC is to extract carbon dioxide from the air and repurpose it. The gas can be stored in deep geological formations, or used to make products such as fuel, chemicals, fizzy drinks and building materials. When the gas is stowed beneath the earth's surface, it is permanently removed from the atmosphere - and can thus even bring about negative carbon emissions.

Various approaches are used for direct air capture. Liquid systems pass air through chemical solutions, which remove the carbon dioxide while returning the other constituent gases to the environment. Solid direct air capture technology makes use of filters that chemically bind with carbon dioxide. When the filters are heated, they release the concentrated gas, which can then be captured for storage or use.

Wim Thiery, a climate scientist at the Vrije Universiteit Brussel in Belgium, views carbon removal as a necessary tool to prevent devastating climate change. "Many 1.5-degree compatible scenarios assume net-zero emissions around 2050, and then, net-negative emissions in the second half of the 21st century," he said.

The UN Intergovernmental Panel on Climate Change concluded in 2018 that billions of tonnes of carbon dioxide may need to be captured and buried after 2050.

But direct air capture is much tougher to carry out than already existing processes that take carbon dioxide from emissions from facilities such as coal-fired power plants. DAC is expensive, harder to scale and much more sophisticated because it deals with far lower concentrations of gas.

Industrial carbon capture and storage (CCS) currently costs about $60 to $120 per tonne of carbon dioxide captured, said Mhairidh Evans, principal analyst at Wood Mackenzie. DAC, by contrast, is priced at $600 per tonne or more because super-heating the air to remove the carbon dioxide takes immense amounts of energy.

Critics of carbon capture costs also say its benefits are too slight. A June report by the Coalition for Negative Emissions (CNE) said the global pipeline of projects in development could remove only about 150 million tonnes of carbon dioxide by 2025. That would make just a tiny dent in global emissions, which crossed a record 59 billion tonnes in 2020.

"If industrial CCS scales up, then that implies a massive build-out of infrastructure for transportation and storage of CO²," Wood Mackenzie's Evans said.

Environmental groups also worry that carbon capture and storage will prove a distraction humanity can ill afford. Greenpeace Japan warned it "should not be publicly funded at the expense of investments for renewable energy and energy efficiency" - or be used as a reason to justify building new fossil fuel power plants.

Bacteria and oilfields

Direct air carbon capture projects are nonetheless an important part of new research such as the Moonshot Research & Development Program launched by Japan in 2020. The billion dollar initiative is partly focused on the fight against global heating.

Current Japanese DAC research includes a project run by Nagoya University, Tokyo University of Science and Nagoya-based company Toho Gas. It aims to harness the energy released when liquefied natural gas (LNG) is turned into gas that is piped into homes and businesses.

In the DAC technique, carbon dioxide is absorbed into an alkaline solution, which then travels to a desorption tower to release the gas under low pressure. The CO² is then LNG-cooled in a sublimation tank to turn it into a solid, known as dry ice. The dry ice, familiar as the mist used as a stage effect in concerts and plays, can then be put to a variety of industrial uses or be stored.

Another early-stage Japanese DAC project makes use of biological agents. Souichiro Kato at Japan's National Institute of Advanced Industrial Science and Technology, is trying to collect carbon dioxide efficiently by genetically modifying a bacterium called Ralstonia eutoropha. The technology could "not only reduce carbon dioxide, but also turn carbon dioxide into a resource" such as bioplastic, Kato said.

Another strand of Japanese research is how to meet the tough challenge of dealing with vast amounts of captured carbon dioxide. The country can store only about 140 billion tonnes of the gas, according to the Global CCS Institute, so it would also need to tap capacity elsewhere. Southeast Asia is often an attractive option, due to numerous depleted oil and gas fields that could be used to inject carbon dioxide underground, an official with Japan's Ministry of Economy, Trade and Industry told Nikkei Asia.

In June, Japan, the U.S., Australia and ten South-East Asian nations launched the Asia CCUS Network to collaborate on carbon capture, utilization and storage. "Southeast Asia has a lot of potential but does not have money, so Japan, the U.S. and Australia would be the financiers," the Japanese government official said.

Another CCUS Network initiative is a plan for Japanese companies and Indonesian partners to launch the first industrial carbon capture and storage operation in Southeast Asia. The work brings Japanese engineering conglomerate JGC Holdings and power generator Electric Power Development together with Indonesia's Pertamina and the Bandung Institute of Technology. The group aims to capture carbon dioxide from natural gas production at Indonesia's Gundih gas field and start injecting it underground by 2025.

A half-hearted embrace

In China, the world's largest emitter of greenhouse gases, carbon capture is officially part of efforts to hit an ambitious goal of carbon neutrality by 2060. But there is skepticism about the country's near-term commitment to the technology.

"Chinese policymakers have only a lukewarm attitude [toward carbon capture, utilization and storage]. Only pilot schemes are in place so far, and none of them can be deployed [at] scale yet," said Yan Qin, a carbon analyst at data firm Refinitiv.

"China has pledged to peak carbon dioxide emissions before 2030. Thus, at present, CCUS is not that attractive since all the focus is on reducing emissions via replacing fossil fuel with clean energy," she added.

China Petrochemical Corp, also known as Sinopec, announced in July the construction of a CCUS project in eastern Shandong province. With annual capture capacity of 1 million tonnes, it is one of t40 CCUS projects in operation or under construction. It is also by far the largest, according to a July report by the Chinese Academy of Environment Planning, a government agency.

But, even when complete, the project would account for only a tiny fraction of the 1.82 billion tonnes of carbon dioxide Beijing has said it wants to capture by 2060. That numerical gulf shows how far geoengineering has to go to become a crucial weapon in the battle against global heating.

The climate moonshot: engineering the earth

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