Can managing solar radiation shape the future of combating climate change?

Can managing solar radiationshapethe future of combating climate change?

Solar Radiation Management (abbreviatedSRM) is perhaps the most controversial of all proposed strategies for preventing climate change. However, as the latest report from the Intergovernmental Panel on Climate Change (IPCC) discusses, its impacts Global warming continues to become more radical than ever; Therefore, our efforts must also become diverse and innovative in dealing with them.

At the current rate of increase of global warming, it is becoming clear that emissions reduction strategies alone will not be sufficient to prevent the severe impacts of climate change that we now face; Therefore, the scientific community is turning to researching and developing solar radiation management engineering techniques, as a potential complementary way to reduce global warming.

Solar engineering – or solar radiation management (SRM) – is a type of climate engineering. The idea behind this technology is to reflect sunlight (solar radiation) back into outer space. This is to limit human-caused climate change.

Solar radiation management concept

Every day, a continuous stream of short-wave ultraviolet rays enters the Earth’s atmosphere, and clouds and atmospheric particles reflect a small percentage of these rays back into space, and then the rest penetrates the Earth’s surface, where it is absorbed. It is then re-radiated as long-wave radiation (infrared).

The large variation in wavelength – combined with the high density of Greenhouse Gases (GHGs) in the lower atmosphere, which absorb these waves and then re-emit them randomly in all directions – explains the large temperature increases found by the Intergovernmental Panel on Climate Change.

The working theory of solar radiation management is very simple: it reflects the ultraviolet rays in sunlight back into space before they are transformed into absorbable long-wave radiation, by increasing the reflective properties of various surfaces. Examples include: genetic engineering of crops to produce brighter leaves, or the use of white paint on surfaces due to its ability to reflect light.

Marine cloud bleaching

As we mentioned, managing solar radiation is a technology that is still under development and research. However, the two most discussed strategies are: “marine cloud bleaching” and “stratospheric aerosol injection,” which operate in the atmosphere as a means of increasing the Earth’s ability to reflect light (albedo). Albedo differs from reflectivity in that it is the ability of objects to reflect all the electromagnetic rays incident on them, regardless of their wavelengths. It also represents the ratio between the total rays falling on a surface and the rays reflected from it.

The first strategy – which is “marine cloud brightening” – works to make the clouds above the oceans and seas lighter; Thus increasing its ability to reflect sunlight back into space. This is done by installing powerful spray systems on top of ships, or above floating stations, to push salty ocean and sea water towards clouds and clouds.

Clouds themselves are a good reflector of sunlight, because of the small droplets of water they contain, and the smaller these droplets that make up the clouds are, the greater their ability to reflect light. Likewise, the greater the number of these small droplets, the greater the ability of the clouds to reflect rays also increases. But in order for more water droplets to form, they need what are known as “condensation nuclei” or “cloud seeds,” which are very small particles that allow the water droplets to By forming above it.

The idea is that when aerosols are added to the atmosphere where clouds form, the tiny atoms suspended in the aerosol act as “condensation nuclei” that allow more small water droplets to form. Thus increasing the brightness of clouds and overcasts.

This method is related to seas and oceans, due to the decrease – or absence – of dust and air pollutants above them; Hence, there is a decrease in the number of particles that act as “condensation nuclei”, but when salt water is sprayed forcefully, the salt grains also act as “condensation nuclei”.

Stratospheric aerosol injection

stratospheric aerosol injection is a proposed method for solar engineering (solar radiation management); To reduce global warming. This strategy works by introducing aerosols into the stratosphere to increase “global dimming”, and in turn the luminosity of the planet, as occurs naturally in massive clouds produced by volcanic eruptions.

Stratospheric aerosol injection (SAI) works by injecting reflective particles directly into the upper atmosphere, which mimics the same natural processes. For example, the eruption of Mount Pinatubo in the Philippines in 1991 led to a powerful release of 20 million tons of solar-reflecting sulfur dioxide; This led to a decrease in the average global temperature by 0.5°C over the next eighteen months.

But to do this in a humane manner, a fleet of high-altitude aircraft would likely be used to inject reflective particles into the upper layers of the atmosphere, such as sodium carbonate or nanoparticles as potential substitutes for sulfur dioxide.

Obstacles to actual implementation

Although it is a promising fast and cost-effective technology to reduce global warming, there is great controversy surrounding it; Because it represents deliberate manipulation of the Earth’s climate, which may lead to disruption of the already fragile climate balance, as many regions around the world suffer from changing rain patterns and even drought, not to mention ozone depletion, in addition to blocking sunlight from large sectors of the oceans that may threaten life below them.

It must be recognized that managing solar radiation does not address the increasing problem of greenhouse gas emissions as the root cause of global warming, but instead compensates for its effects exactly as an analgesic drug does, preventing pain immediately and quickly, but does not address the root of the problem.

The other problem is that managing solar radiation may represent the ideal disguise for interests associated with continued reliance on fossil fuels, but in the end this technology remains one of the promising solutions that can be integrated in light of strict policies towards reducing emissions, but certainly relying on it as a main option is something that cannot be proposed in the first place.