[국제]Solar geoengineering, Pandora’s box or global warming savior?

CNN reported on the 12th that there is a fierce controversy over spraying sulfur dioxide (SO2) into the stratosphere as a solution to stop global warming.

Last year, American startup Make Sunsets launched two balloons filled with sulfur dioxide into the air in Baja California, northwest Mexico.

The plan is to fly balloons filled with helium and small amounts of sulfur dioxide high into the stratosphere and spray them to reflect sunlight to study how the Earth cools.

Scientists who support this method of ‘Solar Geoengineering’ believe it is a solution that cannot be ignored in the face of climate catastrophe.

On the other hand, critics point out that the method is too risky and should not even be studied.

‘Solar geoengineering’ is an attempt to cool the planet Earth by reflecting sunlight or allowing more heat to escape into space.

So far, three main methods have been discussed for this engineering.

One is to sprinkle salt on clouds that float low over the sea to make them brighter and increase light reflection.

The second idea is to spray aerosol particles into the upper Cirrus Clouds to thin the clouds and release more Earth’s heat to the outside.

However, the most studied method is the method of spraying materials into the stratosphere, which was introduced earlier.

This involves spraying, for example, sulfur dioxide particles into the stratosphere 20 km above the ground to reflect sunlight back into space.

Balloons or special airplanes that can fly at high altitudes are used to spray the material.

The material ejection concept was obtained from a volcanic eruption.

When Mount Pinatubo in the Philippines erupted in 1991, sulfur dioxide spewed into the atmosphere had the effect of cooling the earth’s temperature by 0.5 degrees Celsius at one time.

Although this idea of ​​solar geoengineering has been proposed since the 1960s, it has recently attracted attention as the sense of crisis over global warming has increased.

Scientists are even coming up with plans to create sunshades by scattering dust from the moon’s surface to reduce the sun’s light reaching Earth.

Makesunset co-founder Luke Iseman argues, “It would be better without geoengineering, but there are no other realistic alternatives to keeping global temperatures below 2 degrees Celsius.”

While solar geoengineering cannot solve the problem of global warming, proponents argue that it can provide greater cooling at a relatively low cost.

A 2018 Harvard University study estimated this would cost about $2.25 billion annually over 15 years.

David Keith, Professor of Applied Physics at Harvard University, emphasizes that “the world must reduce carbon emissions,” but “other climate change solutions must not be ignored.”

Chris Field, director of the Woods Environmental Institute at Stanford University, says there are ample reasons to be skeptical of solar geoengineering.

However, if geoengineering can provide a solution to reduce the impact of climate change, we have an obligation to try both the risk and the opportunity.

A 2019 survey of more than 700 climate experts found that those who project severe climate damage in their country are more in favor of solar geoengineering.

But opponents of ‘solar geoengineering’ worry that this technology could open a huge ‘Pandora’s box’.

There are concerns that tampering with Earth’s thermostats could change rainfall patterns and shift monsoons, with potentially devastating consequences for crops.

It also increases the potential for conflicts of interest, where the impacts of climate change vary from region to region, with some regions benefiting while others suffer.

“When things go wrong, people in poor countries suffer the most,” said Professor Choukumerize Okereke, a prominent Nigerian climate expert.

He stressed that African countries are already being used as proving grounds for technology.

It is also emphasized that solar geoengineering can damage the ozone layer that protects the earth from harmful ultraviolet rays.

It has recently been observed that the current ozone layer is gradually recovering from damage as the use of Freon gas has been banned since the 1980s and alternative materials have been introduced.

There is also an analysis that geoengineering has technical difficulties.

Aerosol particles tend not to remain in the atmosphere for more than about a year, so continuous dissemination is a challenge.

Professor Raymond Pierrehumbert of the Department of Physics at the University of Oxford, UK, said geoengineering “risks an ‘apocalypse shock’ if interrupted, causing all the pent-up warming that is poised to hit the planet.”

One of the biggest criticisms of ‘solar geoengineering’ is that it can signal to ‘polluters’ that they can continue to emit pollutants, while distracting governments from policies about pollution that cause global warming. no see.

So in 2021, 400 scientists called for an “international ban” to limit the development of solar geoengineering “before it’s too late.”

The argument is that solar geoengineering should be banned in the same way as chemical and biological weapons, nuclear testing, and northern lights mining.

However, interest in geoengineering technology is growing rapidly, especially in the United States.

In 2019, Congress allocated $4 million to the National Oceanic and Atmospheric Administration for stratospheric research.

And last year, the Biden administration announced a five-year research plan to explore this concept.

In a 2021 report, the National Academy of Sciences called for the United States to allocate up to $200 million to research programs aimed at better understanding the feasibility of solar geoengineering, its impact on society and the environment, and public perception.

However, geoengineering experiments so far have faced several challenges.

An attempt by Harvard University researchers to test a high-altitude balloon in Arctic Sweden in 2021 was canceled due to protests from local natives.

Indigenous people feared that solar geoengineering “posed catastrophic risks.”

In January, the Mexican government said it would “ban experiments using solar geoengineering” after Makesunset launched a balloon last year.

YTN Lim Soo-geun (sglim@ytn.co.kr)

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