Cloudy with a chance of artificial rain

The shield of nature

Earth's climate depends on two main factors: the solar radiation it receives and the way it manages this received energy. 71% of this energy is absorbed and then released in the form of infrared radiation. The CO₂ in the atmosphere captures some of this radiation and prevents it from escaping, causing temperatures to rise. This is the dreaded greenhouse effect and the reason why climate change is such a growing concern. In the summer of 2021, temperatures soared, reaching almost 50°C in Canada. It is more urgent than ever to act, and researchers are already turning to a potential solution: geoengineering.

What if humanity could control the climate in 2051? Stopping the rise in temperature is a non-negotiable for the survival of mankind. Research into geoengineering will quickly become a global project, likely in response to a catastrophic event that will force governments to act decisively (much like during a pandemic).

Every year, for one week, air-raids will take off to distribute aerosols into the stratosphere. Their route will follow the equator, spreading aerosols freely around both hemispheres, and creating a light, protective cloud cover capable of reducing solar radiation by 1%. Temperatures on Earth will then be better controlled, and summer heat spikes will become increasingly rare.

The effectiveness of this initiative will encourage researchers to turn to maritime stratocumulus clouds. Lightening these thick clouds will make it possible to create a protective screen against solar radiation, thanks to its high reflection capacity. How can this be done? By injecting salt particles from sea water directly into these clouds. This initiative will be applied locally to lower temperatures and prevent coral reef bleaching.

Governments will encourage roof renovation for homes and other buildings with high albedo materials (the measure of reflectivity of a material). New buildings will come with these types of roofing as standard, which will reflect the sun's rays in a more optimal way. In summer, glaciers will be covered with large reflective tarpaulins to preserve them, while largely shielding most of the sun's rays.

In parallel, efforts to absorb CO₂ emissions – released as a result of industrial activity – will be hugely ramped up. The cultivation of phytoplankton will be commonplace, absorbing up to 50% of these emissions by transforming them into sediment. Reforestation projects will be widely supported, including in some desert areas.

A coalition of researchers and engineers will work tirelessly on a project of interstellar proportions. It will be a reflective orbital satellite that will act as a giant, travelling mirror. It will reflect the sun's rays before they even enter the Earth's atmosphere.

These initiatives will buy humanity time to find a way to further reduce their CO₂ emissions and adapt to future growth. This is not a quick fix or an excuse for inaction. To avoid a terminal shock phase, we need a complete rethink of how economies and societies function. A phase in which, if geoengineering initiatives were to end for whatever reason, the effects of climate disruption would be felt even more quickly and strongly than before, spelling the end of humanity.

Controlling Earth’s thermostat

Pure science fiction? Not entirely. Leading scientists are already looking into the subject and many research studies have been done. Dr Anthony Jones, a scientist working on the Earth's atmosphere at the University of Exeter, has highlighted the fact that injecting aerosols into the stratosphere could be particularly effective. He draws parallels with the 1991 eruption of Mount Pinatubo in the Philippines, which was so violent that millions of sulphur dioxide particles were suspended in the atmosphere, creating a protective veil that caused mean global temperatures to cool by 0.5°C for several years.

In the race to cool our burning planet, it seems the old adage might be true - every cloud has a silver lining. Researchers Douglas G. MacMartin, Katharine L. Ricke and David W. Keith have been working on the effects of injecting salt particles into marine stratocumulus clouds, which could help to cool local temperatures. In addition, studies by John Latham, Joan Kleypas, Rachel Hauser, Ben Parkes and Alan Gadian show that this initiative could have a positive effect on coral reef bleaching. The marine clouds would reflect sunlight more effectively and thus lower ocean surface temperatures. This would prevent coral death caused by rising temperatures.

Materials with a high albedo are already used to optimise the reflection of solar radiation. Swiss citizens have undertaken to cover nine of their glaciers, including the Rhone glacier, with large, white blankets to prevent them from melting. According to glaciologist David Volken, this could reduce melting by up to 70%. Research groups from the Heinrich Böll Foundation and the ETC Group support this initiative, opening new possibilities for the use of high-albedo materials, especially in construction.

Scientists at the Divecha Centre for Climate Change in India are seriously exploring the idea of launching an orbiting satellite that would reflect solar radiation. Even a 2% drop in solar radiation could make a big difference and considerably limit a rise in temperature. This project is therefore a great opportunity, but it requires the use of more advanced technologies than those we have today.

Absorbing CO₂ emissions through natural elements – such as phytoplankton or trees – has been well-trodden ground since the end of the 20th century. Just look at the buzz around reforestation projects in 2021. These include initiatives such as The Great Green Wall, which aims to create a climate barrier in the arid region of the African Sahel, thus halting the desertification process. The project should be completed by 2030 and may be a source of inspiration for similar initiatives in other parts of the world. The possibility of fertilising the oceans is also being explored as it could absorb between 30 and 50% of our CO₂ emissions.

What if there was a simple hack anyone could use to dabble with climate change? A whitepaper from Harvard Kennedy School’s Belfer Center posed an interesting scenario for geoengineering taken out of government’s hands. According to the piece, hobbyist kits for unmanned, high-altitude balloons can already be purchased for as little as $25. Imagine what would happen if someone launched a campaign via social media, calling on every citizen to launch high-altitude balloons into the sky. Each balloon would carry a small payload of particles that could reflect heat back into space – something that would be completely doable by mixing helium with sulphur dioxide.

Who knows, perhaps rogue acts like these – mild forms of green terrorism – will be exactly what our society needs to wake up and smell the coffee…brewed with a melted glacier? Think of it as democratising technology for the greater good.

Geoengineering encompasses a wide range of techniques to control the Earth's thermostat. Some, such as covering glaciers with large white blankets, are in use already and could easily be deployed on a global scale. Others are well under way but still require further research. Injecting aerosols into the stratosphere is theoretically possible with current technologies, but the right aerosol formula has yet to be found. The use of certain particles – such as sulphur dioxide – could actually be more devastating than beneficial.

Will we be using geoengineering by 2051 to try to counter the effects of climate change? Certainly. Getting a reflective satellite up and running may take some time and injecting aerosols into the stratosphere still need a few more years of research to come to life. These interventions also raise some interesting questions about who should be in control of how we tinker with the Earth’s climate. Some even speculate that we could be heading for climate wars.

Either way, these methods give hope to humanity. It’s comforting to know that there are ways to artificially halt the rise in temperatures while humans adapt to a new normal. It’s exciting to know that not only could we maintain the current status quo of our beautiful planet, but even turn back the clock.