In July last year and again this year I was one of some 1,000 people who paid a $1 so that I could dim the sun just for a tiny bit, to save the world from climate change.  It wasn't a scam, but a promise sold by a California start-up called Make Sunsets.  My two dollars paid for founder Luke Iseman to release balloons loaded with sulphur dioxide   ̶   an air pollutant normally spewed by volcanic eruptions.  The idea was that, when the balloons burst in the stratosphere, the particles released from it would block sunlight and cool the planet.   Tell the truth, I did not feel any difference.

Iseman's sun-blocking activities are an example of a controversial tactic called "solar geoengineering." It has been the subject of many science fiction stories and conspiracy theories.  There are plenty of proposals how to bounce sunlight away from Earth to lower temperatures, including sprinkling reflective particles into the stratosphere, making clouds shinier, and launching giant space mirrors into orbit. 

Who hasn't noticed civil aircraft overflying Malta leaving trails behind them?  I for one am not convinced this is necessarily the effect of condensation from jet engines. There is no EU law that prohibits cloud seeding   ̶   the dispersal of substances like silver iodide into clouds to induce rain or snow, or to reduce hail. 

Geoengineering   ̶   deliberately intervening in the Earth's climate system to mitigate the impacts of global warming   ̶   is one of the most controversial areas of climate research.   The ideas, ranging from removing planet-warming carbon dioxide from the atmosphere via planting trees to even more radical geoengineering ideas like "reflecting sunlight," are part of the net zero agenda. Net zero is achieved when the amount of planet-warming greenhouse gases produced by human activities is exactly offset by the amount being actively removed from the atmosphere.

Supporters of these ideas think it is worth exploring what could help curb rapidly rising temperatures, which are already having severe impacts on people and ecosystems around the globe.  Others like author Martin Siegert, professor of geosciences at the University of Exeter, think that these techniques "are dealing with the symptoms of climate change rather than the causes."  Opponents argue the risks are simply too great.

Others put great hopes on geoengineering.  One place where solar geoengineering has broad public support is Australia, where oceanographer Daniel Harrison of Southern Cross University has been leading a cloud brightening project for the last five years.  Scientists have been spraying saltwater particles into the sky at regular intervals from a ship over the Great Barrier Reef.  Once the tiny particles reach existing clouds, the water vapour they attract swells to 500,000 times their size, forming visible droplets.

The University is aiming to discover whether the salt particles will increase the clouds' reflectivity, bouncing more sunlight back into space before it hits the water. Should it succeed, the technology might cool the ocean enough to prevent the death of the Great Barrier Reef.  The Great Barrier Reef is traditionally owned by more than 70 Indigenous groups. The researchers obtained permission from every group whose stretch of sea was contiguous with their proposed testing area.

Nevertheless, it is feared that, while some of the ideas may be theoretically possible, the enormous costs and time to scale-up mean they are extremely unlikely to make a difference.  For example, some researchers have proposed a plan to pump seawater over the surface of Arctic sea-ice in winter; by thickening it, they would give the ice a better chance to survive the summer.  But to cover 10% of the Arctic could require about 10 million seawater pumps, one estimate suggests.

More than 40 researchers recently got together to warn that climate engineering in the polar region could bring "severe environmental damage" and urged countries to simply focus on reaching net zero, the only established way to limit global warming.  The scientists' review, reproduced in the journal Frontiers in Science, assessed the evidence from five of the most widely discussed polar geoengineering ideas.  All failed to meet basic criteria for their feasibility and potential environmental risks, the scientists said.

At best, even supporters of geoengineering research agree that this would be a supplement to net zero, not a substitute.  "The need for emissions reductions comes first ... almost anything we do is futile without it," according to Dr Shaun Fitzgerald, director of the University of Cambridge's Centre for Climate Repair.  Dr Fitzgerald acknowledges that investigation might indeed find that the ideas for large-scale geoengineering are "bonkers."

Geoengineering methods are touted to be cheaper and faster than making the world run on clean energy and removing tonnes of carbon dioxide from the air. Researchers at Yale and Harvard have estimated that halving the rate of global warming for 15 years by dusting the stratosphere with sulphur dioxide would cost about $2.25 billion per year but still be substantially less than the cost of climate catastrophes.

Make Sunsets raised more than $1 million from investors and sold more than $100,000 worth of "cooling credits" to customers last year.  Another one called Stardust raised $75 million to develop a more sophisticated geoengineering method and launch it by the end of the decade.

The role of private firms in tinkering with the global climate is sparking a heated debate whether profit-seeking companies should be allowed to develop technologies designed to affect everyone on Earth.  After all, who knows whether geoengineering might have unintended consequences for global weather patterns that could kill people by raising air pollution and cancer rates?

"I do not trust the private sector to make good decisions for people," says Shuchi Talati, founder of the non-profit Alliance for Just Deliberation on Solar Geoengineering. "The whole move-fast-and-break-things ethos   ̶   I've seen it, and it hasn't gone particularly well for society."

The problem is that most governments have no specific geoengineering regulations, except for a patchwork of laws and international treaties on air pollution.  It is doubtful that they apply to weather modifications.  Some states in the USA have banned the practice, others were considering doing so until recently.  President Trump's recent scrapping of all climate change legislation could make geoengineering a fertile ground for Wild West practices.

Meanwhile, private geoengineering companies have few rules to follow.  Most geoengineering experts reject a swashbuckling approach and say that deployment decisions should be left to governments.  "Scientists should study the risks and benefits so that elected leaders and civil society can make informed choices," says David Keith, the founding faculty director of the Climate Systems Engineering initiative at the University of Chicago.

There is also the issue that geoengineering in one country will inevitably affect what happens to the climate in other countries, possibly for the worse.  "If a country were to deploy geoengineering against the wishes of others, it could increase geopolitical tensions in polar regions," according to Dr Valerie Masson-Delmotte, senior scientist at the Université Paris Saclay in France.

Deliberately altering how the planet works sounds ambitious, even arrogant. Inevitably, it raises concerns about meddling with nature: who decides when and where the technologies should be deployed.  Some experts believe the public shouldn't be involved in decision-making, citing concerns about people manipulated by misinformation making consequential decisions. Others emphasise that open consultation on climate engineering shouldn't be limited to approving or rejecting particular projects but should allow people to consider and debate the technologies more broadly.

Clearly, certain geoengineering technologies pose cross-border risks to national political and economic interests.  One cannot exclude the possibility that certain technologies might be weaponized.  In Europe, in contrast with the USA, there would be concerns regarding private sector initiatives driven by purely commercial interests. Another factor relates to the risk that geoengineering technologies and resources might be dominated by a small group of companies or even by a single country.  These and other considerations are all potential sources of global tensions or conflicts.  

Malta is disproportionately affected by climate change driven by the global emissions of larger, more industrialized nations.  It is particularly vulnerable to climate change resulting in sea-level rise, increasing temperatures, and reduced precipitation, yet has limited capability to mitigate them. Contrarily, it will likewise be vulnerable to geoengineering by other countries over which it has no control.  

I might be wrong, but I am not aware that the issues involved are being researched and discussed by anybody in Malta.  Although the Institute for Climate Change and Sustainable Development at the University of Malta conducts research about various aspects of the climate, it does not appear to have any research or projects related to geoengineering. 

In this context international cooperation will be needed to ensure a global consensus on the use of geoengineering technologies.   That word "consensus" would obviously be anathema to a transactional government like Trump's, while there is no reason to believe that a post-Trump GOP would be more amenable to international agreements.  While the EU is not yet a key player in the geoengineering sector, it should step up.  Being caught on the wrong foot again would be suicidal.

But the first question we need to answer is whether geoengineering is "a nightmare fix for climate change," as claimed by Jeff Goodel, the prominent American environmental journalist, author, and climate expert, or whether geoengineering is the kind of change which makes sense if you "plunge into it, move with it, and join the dance," as the English philosopher Alan Watts suggests.