Can geo-engineering help save the planet? – BBC News

Conspiracy theories talk about geo-engineering, but can it help save the planet?

If we can’t control global warming by drastically reducing carbon, could something called geo-engineering be a way to cool the world?

In what has become a £103bn ($135bn) industry, scientists around the world, including the UK, are researching geo-engineering – ways to control the climate to deal with global warming the world.

Some experts worry that there are too many risks associated with it, fearing that it could damage the world’s climate or heat up other areas, not heal them.

As the industry grows, so do conspiracy theories. BBC Weather has seen a huge increase in social media comments about geo-engineering since January, accusing us of hiding secret agendas and wrongly blaming geo-engineering for cooler weather and the moisture we just had. Globally, there are twice as many mentions of geoengineering this year on X, formerly known as Twitter, than in the previous six months of 2023.

Other geoengineering ideas include beaming sunlight back into space to cool the Earth. The most advanced area of ​​geo-engineering is direct atmospheric carbon capture with small-scale installations operating across Europe, the US and Canada. These currently remove around 10,000 tonnes of carbon dioxide a year (a third of London’s annual emissions), meaning they would need to increase significantly to make any difference to the millions of tonnes 35 thousand that we take out all over the world.

Professor Liz Bentley, chief executive of the Royal Meteorological Society, says: “We need to start thinking about what we can do to limit any warming. “That’s where geo-engineering starts to become an interesting conversation.”

In addition to the fear of exacerbating the effects of climate change, some experts worry that the lure of geo-engineering as a quick fix could also hinder efforts to reduce carbon emissions.

It’s not as surprising as it seems

It sounds like the stuff of science fiction, but the concept of solar radiation, the technical term for sunlight, isn’t as crazy as it sounds and sometimes happens in the natural world. During a volcanic eruption, large amounts of ash and aerosols – tiny particles – can be transported to high altitudes that can reflect sunlight back into space.

Image source, Getty Images

Image description, When Mount Pinatubo erupted in 1991 it cooled the world’s temperature

The 1991 eruption of Mount Pinatubo in the Philippines led to a 0.5C cooling of global temperatures over the next few years.

So, can we really simulate a volcano to cool our planet?

Professor Jim Haywood, an atmospheric scientist at the University of Exeter, urges caution. “I really want to know about the harmful effects of climate change, but also about the possible side effects and harmful effects of any solar radiation system,” he said.

Researchers are studying two types of solar radiation control: sea cloud brightening and stratospheric aerosol injection.

Cloud lighting involves spraying very fine salt water from a ship onto the low clouds above the ocean to enhance their brightness and sparkle.

Modeling has shown that if you sprinkled a large area – about 4% of the ocean – near the equator with light clouds, the combination of more clouds and as a result lower sea temperatures under it you can have influence all over the world.

Our atmosphere is complex, infinite and behaves like a fluid. You may have come across the ‘butterfly effect’ where if a butterfly flapped its wings in Mexico, it would bring rain to the UK. While that’s actually a big jump, it highlights how the weather is interconnected around the world.

“Lightning a cloud on the coast of Namibia can cause drought in South America, especially in Brazil. What is there in Brazil? Well, rainforests,” said Professor Haywood.

This time, due to the complex atmosphere-ocean circulation, increasing cloudiness would cool the sea surface in the eastern part of the south Atlantic, meaning that the precipitation pattern would be negatively affected across the Atlantic. south of South America. Drought in the Amazon rainforest – often called the ‘lungs of the planet’ as it absorbs carbon dioxide – could cause significant damage.

While the focus has been on using ocean light to reduce global warming, others see the potential for using it on a much smaller scale.

Following a major coral bleaching event in 2016 on the Great Barrier Reef, scientists at Southern Cross University in Australia are experimenting with cloud brightening to protect and cool coral-rich reef areas. to prevent bleaching during sea heat.

Image source, Southern Cross University

Image description, Clouds have been trained to try to protect the Great Barrier Reef

“While we are in the process of understanding how the luminescence of ocean clouds can be used over the Great Barrier Reef, we have made great scientific progress.

“We have greatly increased our confidence that the clouds above the rocks can be bright,” said Professor Daniel Harrison, project leader at Southern Cross University.

Stratospheric technology development

The technology to create small-scale cloudbursts with fans and sprayers already exists, but another method of solar radiation management – stratospheric aerosol injection – will require development. first large to have the desired effect.

This geo-engineering method involves artificially injecting aerosols such as sulphate into the stratosphere, which ranges from 6-12 miles (10-20km) to 31 miles (50km) above the Earth. These aerosols would reflect the sun’s rays, reducing the amount reaching our planet’s surface and thought to cause global cooling.

Image source, Getty Images

Image description, The Great Barrier Reef has a problem with over-darkening

Whether sufficient aerosols can be injected into the stratosphere is not known, but aircraft capable of flying at an altitude of 11 miles (18km) – about 1.5 times that of a commercial airliner – is a proposal. one.

Millions of tons of sulfur dioxide would need to be injected to have any impact. For example, during the eruption of Mount Pinatubo, half of the world’s cooling rate was due to the release of 15 million tons of sulfur dioxide into the stratosphere.

Because sulphate aerosols last only a few years in the atmosphere compared to the decades that carbon dioxide lasts, stratospheric aerosol injection is only seen as a temporary process.

This has not stopped one US company from starting to sell ‘cool loans’. For payment they will send a balloon filled with sulfur dioxide into the stratosphere, where it will explode and release the gas.

They suggest that one of their cooling bills – two grams of sulfur dioxide – will “reduce one ton of carbon dioxide emissions for the year”. That’s the equivalent of a single-passenger return flight between Paris and New York, meaning a lot of balloons would be needed for this to have any kind of cooling effect.

As with marine cloud cover, there are also risks of stratospheric aerosol injection. In a study earlier this year, a computer model found that stratospheric aerosol injection could cause intense heat 15km above the tropics that could alter large-scale weather patterns, warming the polar regions and changing climate patterns. rain on the land.

“The environmental effects are largely unknown,” said Professor Bentley. “We can reduce the average global temperature [rise]but in fact we may be making things worse in certain parts of the world”.

Risk warnings

This brings us to the fundamental questions about trust and the risks involved in mediation. In 2022, hundreds of scientists signed an open letter calling for a global agreement that does not regulate solar radiation.

They said the increasing development calls give “cause for concern” about the risks involved which are “poorly understood” and a potential disincentive for governments, businesses and communities from decarbonising.

The team is worried that even doing theoretical research will lead to real-world experiments without fully knowing the problems. But some scientists think that the risk of researching solar radiation control is less than the risk of relying solely on decarbonisation.

In addition, some say that misinformation and conspirators are preventing them from doing research.

Dr Ramit Debnath, an assistant professor at Cambridge University, says “many funders are very skeptical about funding research” because they fear being attacked by conspirators. He analyzed nearly 2 million tweets with the hashtag #GeoEngineering and found that more than 70% of people expressed negative views about solar radiation management and many of them were conspiracy theories.

Image source, Getty Images

Image description, Contrails are known as ‘chemtrails’ by some conspiracy theorists

One of these is related to ‘chemtrails’, a widely publicized conspiracy theory about a secret plan to spray people with dangerous chemicals, suggesting that white streams of the sky from the back of the plane is proof of this. These are actually the trails of water vapor – known as contrails – from the jet engines.

Contrails at this height actually absorb the sun’s rays and heat the planet, so they are not relevant to the geo-engineering techniques currently being explored.

Dr Debnath said that when he spoke about the solar system on social media, he was accused of “trying to kill people and control people’s lives”.

The solar system is being treated with caution – the UK government has not used these methods and “has no plans to do so”. However, they invest.

The Environmental Research Council has invited applications for the £10.5m fund and to “provide ‘risk assessment'” to assess whether the negative effects of the practice outweigh the potential damage caused by the change. the weather.

“It is not a silver bullet that will solve everything,” said Professor Bentley. But it may be part of a series of solutions.

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