Cloud brightening, cirrus cloud thinning, space-based techniques, and stratospheric aerosols – no, it is not science fiction.
People are concerned about climate change largely because of its impacts on people and ecosystems. Its impact on agriculture is of particular importance, as well as the changes in weather patterns – prolonged droughts, intense heat, and flooding from extreme rainfall.
Looking for ways to change the harmful effects of carbon dioxide emissions is not new. One of the earliest documented mentions of using sunlight to change the effects of climate change occurred in 1965.
In a report titled “Restoring the Quality of Our Environment,” scientists talked about “deliberately bringing about countervailing climatic changes,” including “raising the albedo, or reflectivity, of the Earth.”
Albedo is the fraction of light that a surface reflects. If it is all reflected, the albedo is equal to 1. If 30% is reflected, the albedo is 0.3. The albedo of Earth’s surface (atmosphere, ocean, land surfaces) determines how much incoming solar energy, or light, is immediately reflected back to space. This can have an impact on climate.
Today, as the world has taken a more hands-on approach in attempting to deal with the worsening impacts of climate change, solar geoengineering has become the supposed magic answer to mankind’s problem.
A growing number of scientists and policymakers are urging further study of solar geoengineering, recognizing that emissions cuts alone will not limit dangerous climate change and that additional innovations may be needed.
What is solar geoengineering?
Basically, solar geoengineering is a type of climate engineering in which sunlight (solar radiation) would be reflected back to outer space to limit human-caused climate change.
This is not a substitute for reducing greenhouse gases – but a temporary measure to limit warming while emissions of greenhouse gases are reduced and carbon dioxide is removed.
Climate models suggest that a moderate magnitude of solar geoengineering would bring important aspects of the climate – for example, average and extreme temperature, water availability, and cyclone intensity – closer to their preindustrial values at a subregional resolution.
However, the Intergovernmental Panel on Climate Change (IPCC) concluded in its Sixth Assessment Report that there are high risks associated with strategies such as solar radiation management (SRM), planting forests in unnatural locations; or “poorly implemented bioenergy, with or without carbon capture and storage.
The pros and cons of solar geoengineering
When used in moderation and combined with emissions cuts, solar geoengineering has the potential to reduce climate changes around the globe. For example, it could reduce climate impacts such as extreme temperatures, changes in water availability, and the intensity of tropical storms.
Research could reduce uncertainty about the technology’s potential benefits and risks, but, for decades, research in solar geoengineering has been limited. That said, many scientists believe that solar geoengineering could cool the planet within months after deployment, while we act to reduce climate risk while cutting emissions and scaling up carbon dioxide removal.
In 2015, a very interesting study on Climate Intervention was published. One of the two volumes in the report discusses albedo modification – changing the fraction of incoming solar radiation that reaches the surface.
This approach would deliberately modify the energy budget of Earth to produce a cooling designed to compensate for some of the effects of warming associated with greenhouse gas increases.
The prospect of large-scale albedo modification raises political and governance issues at national and global levels, as well as ethical concerns, the authors of the study write.
And while solar geoengineering holds promise for reducing global temperatures, absent any international agreements, it could also spark conflict, reports the Washington Post.
Interestingly, many countries are already viewing solar geoengineering as a threat to their own citizens and may be prepared with a military response.
Members of the U.S. intelligence community and other national security officials were concerned enough last year that they decided to plot how to avert a war triggered by this kind of climate engineering.
In a role-playing exercise, they practiced managing the tensions that would be unleashed, according to people familiar with the exercise, a sign that they see it as a credible threat in need of a strategy.
And if you are thinking that it would be silly to get all bent out of shape over a country using solar geoengineering, or even just running a few tests to see if it works – think again.
Two weather balloons lead to Mexico’s ban on solar geoengineering
Entrepreneur Luke Iseman, the founder of a U.S. startup called Make Sunsets released two weather balloons containing sulfur dioxide into the atmosphere over Mexico’s Baja California one day in April last year.
Sulfur dioxide (SO2) is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic activity and is produced as a by-product of copper extraction and the burning of sulfur-bearing fossil fuels.
Additionally, injecting sulfur dioxide into the atmosphere could damage the ozone layer, cause respiratory illness, and create acid rain.
Letting the balloons float toward the stratosphere, Iseman believed the sulfur dioxide in the balloons would deflect sunlight and cool the atmosphere, a controversial climate strategy known as solar geoengineering. Mexico said the launch violated its national sovereignty.
The unauthorized release, which became public in January, has already had an impact: setting off a series of responses that could set the rules for future study of geoengineering, especially by private companies, in Mexico and around the world., according to Reuters.
The Mexican government told Reuters it is now actively drafting “new regulations and standards” to prohibit solar geoengineering inside the country. Mexico also plans to rally other countries to ban the climate strategy, a senior government official told Reuters.
Climate policy experts said Mexico is in a position to help set the rules for future geoengineering research.
“A country like Mexico could start pulling together other countries and say: ‘Let’s work on this together and see how we can ban it together or make it happen properly together,’” said Janos Pasztor, executive director of the Carnegie Climate Governance Initiative (C2G), which advises on the governance of solar geoengineering and other climate-altering technologies.
