Dusseldorf The earth heats up year by year. Last summer, record temperatures of over 42 degrees were measured not only in Germany. Half of Europe experienced one heat record after another in 2019 – consequences of climate change. The temperature on earth has risen on average by one degree Celsius in the past decades.
The proportion of CO2 in the atmosphere has more than doubled and natural disasters such as droughts, floods or severe storms are increasing every year. For more than 50 years, mankind has known about the dangers of progressive climate change. Little has happened since then.
Before the corona virus spread worldwide, however, global warming had finally reached the top of the agenda of heads of state and government. Corporations, governments and industries are stepping up their efforts, wanting to become climate neutral and increasingly relying on alternative energies such as wind, solar, biomass or green hydrogen instead of fossil fuels. Your goal: avoid as much CO2 as possible. But is that enough?
Experts from the IPCC put this into question. In their 2018 special report, the scientists made it clear that the 1.5-degree target of the Paris climate agreement could hardly be achieved with CO2 savings alone. This opens the field to a niche that was long excluded from the climate science and political mainstream: so-called geo-engineering.
The term describes the manipulation of the climate system using technology on a very large scale. The ideas range from mirrors in space that keep solar radiation away from the earth, an artificially created algal bloom that eats CO2, and manipulation of the weather, for example with the help of self-made clouds.
“In the past, it all came under the umbrella term of geo-engineering. Today, a distinction is made between the removal of CO2 from the atmosphere and solar radiation management, which is intended to reflect sunlight back into space so that the earth does not heat up further, ”explains climate scientist Sabine Fuss from the climate research institute Mercator (MCC). The technical terms are “CO2 Removal” (CO2 extraction) and solar radiation management. “By definition, the term geoengineering actually doesn’t exist anymore,” says Fuss.
The corresponding high-tech solutions for the climate, however, do. The start-up Climeworks from Switzerland, whose founders come from Germany, is currently particularly popular. The two engineers Jan Wurzbacher and Christoph Gebald invented a kind of vacuum cleaner that draws CO2 from the atmosphere.
Collectors filter the carbon dioxide from the environment and purify the air from the greenhouse gas. Gebald once said that the Apple of renewable energies should become climeworks. The two have already raised around 50 million euros from international donors, including Audi investing in the green start-up.
“Of course, trees and plants also draw CO2 from the atmosphere. But our technology requires around 400 times less space, ”Climeworks manager Christoph Beuttler explains the concept of the young company, which has only been commercial for two years. Climeworks was previously a research project at ETH Zurich.
The filtered carbon dioxide is sold, for example to Coca Cola or Hellenic, who use it to make beverages. The greenhouse gas is thus split off and processed, also called “carbon capture and usage”. Climeworks also plans to enter carbon storage and carbon capture and storage (CCS) soon.
“We are currently planning the construction of our largest plant to date, which produces negative emissions. The CO2 is drawn from the atmosphere, pumped into basalt rock a few hundred meters deep, with which it reacts and is mineralized, ”explains Beuttler. This way, the carbon dioxide is stored safely forever.
Climeworks does not see an alternative to an extensive reduction in CO2 emissions in its own technology. “Such an industry would have to grow around 60 percent a year and with it, of course, renewable energies to ensure a green energy supply. We cannot build a billion dollar industry overnight, ”warns the manager. Climeworks does not yet make any money with its technology.
But there is no longer any doubt that the once futuristic idea of CO2 elimination will become a billion dollar industry. Among others, the oil giant Chevron, the commodity group BHP Billiton and Microsoft founder Bill Gates have joined the competition from the USA. Investors who are not only concerned with a green conscience – they want returns. Tech start-ups all over the world are vying for the best method: Global Thermostat from the USA, Ineratec from Karlsruhe, Climeworks from Zurich and also Carbon Engineering from Canada are promising candidates.
Unlike its Swiss competition, Carbon Engineering uses a similar technology on a very large scale: The company’s first commercial plant is currently being built in the US state of Texas. Up to one million tons of CO2 are to be extracted from the air by 2023. “It is relatively cheap to switch from coal to renewables and it is relatively cheap to switch from internal combustion engines to electric cars. However, it is much more difficult to enable CO2-free flying. But we also have to get these emissions under control, ”CEO Steve Oldham is convinced.
At the moment, however, the use of CO2 capture still fails because of its economy – after all, it consumes a lot of energy. With the new plant in Texas, however, the cost of currently around $ 600 per tonne of CO2 extracted is expected to drop to $ 150 per tonne. “We need negative emissions on a large scale,” Oldham is convinced.
A fight against time
In order to keep global warming below two degrees, according to climate researchers, human beings are only allowed to emit 700 billion tons of greenhouse gases by 2100. Even with rapidly declining emissions, this limit would have been reached in the 1930s. After that, not a gram of greenhouse gas should be released. Since this is completely unrealistic, the IPCC has long assumed that humanity must intervene.
More and more scientists believe that the possible turning point in the fight against climate change has already been passed and therefore see saving and reducing CO2 consumption in technical innovations as the last resort.
Others, like the US environmental organization CIEL, fear that geoengineering will be used as an excuse to continue as before. In a joint study with the Heinrich Böll Foundation, she warns that technologies such as the separation and storage of CO2 make people believe that more and more coal, oil and gas can be produced, and the world is still below 1.5 -Grad brand remains.
Oil companies such as Chevron, BHP and Occidental are also investing large amounts of millions in the Canadian start-up Carbon Engineering. CEO Oldham does not see a conflict in this, however. “We can draw CO2 from the atmosphere, but we can neither store it nor process it into fuel. And this is where the oil companies offer us enormous expertise, ”he says. Interest in so-called direct air capture technologies (DAC) is also increasing among other companies.
“We know exactly how it works, what impact it has, and how big it is,” says Oldham. That is why he would not assign DAC to the generic term geo-engineering. “You can stop drawing CO2 from the atmosphere at any time. It’s different with many geoengineering ideas, ”says the Canadian. And that’s exactly what makes them so dangerous.
Ulrike Niemeier also warns that some inventions should rather only be regarded as an absolute emergency solution and best kept under lock and key with regard to their own work. At the Max Planck Institute for Meteorology, she conducts research on the consequences of using sulfur particles to cool the temperature on Earth. An idea that falls under the term “Solar Radiation Management” (SRM).
So-called solar radiation management is viewed much more critically than the absorption of CO2 from the atmosphere. From artificial clouds to mirrors in space or sulfur particles in the stratosphere, there are many approaches to lower the temperature on Earth. “The idea behind this is to bring sulfur particles, so-called aerosols, into the stratosphere, where they would act like a kind of parasol for the earth and thus cool the climate,” explains the scientist.
A risky technology
The idea is not new. The model is a very old, natural process: When volcanoes erupt, they throw tiny particles with sulfur compounds into the stratosphere. The large amounts of dust, ash and sulfur compounds shield part of the sun’s rays and thus verifiably lower the temperature on earth.
Exactly this effect could also be created artificially. “We are researching this technology because we want to know exactly how it works and what effects it would have,” says Niemeier. “So far, however, there have been almost exclusively theoretical studies on this topic. We are still at the very beginning. ”
Several research groups in the USA now want to test this theoretical possibility in a small experiment called Scopex. But there are many controversies for many reasons. Such an intervention in the climate system would have hardly foreseeable risks on a large scale. It could affect the water cycle, change precipitation patterns and slow down the formation of the ozone layer. Nevertheless, there are many supporters of the “blackout theory”. Among others, Microsoft founder Bill Gates. The multi-billionaire financed the Scopex experiment.
Behind it is probably the best known advocate of solar radiation, David Keith. The Harvard researcher has been researching the possibility of cooling the earth using technology for years and is a co-founder of the DAC start-up Carbon Engineering. “In the best case, it saves mankind from climate change, in the worst case, it can wipe out life on earth,” Keith once described the use of particles in the stratosphere in the fight against global warming.
The advantage of the volcano method: it would work quickly and would be relatively cheap. Experts estimate the cost to be a few billion dollars a year. “It is a technology that I hope will never be used,” says Niemeier of her own research. The risks to the environment and politics are too high.
Because once you start with solar radiation management, you can’t stop it so easily. Otherwise there would be a sudden, catastrophic warming of the earth. The particles in the atmosphere are short-lived, the effect would fizzle out quickly. Not to mention the political dangers.
The screen would look strong in the tropics, for example, but not at all on the polar night. This would change evaporation patterns and temperature gradients. For many, such unpredictable climatic side effects are what make the approach so dangerous.
“The uncertainties regarding the use of sulfur particles are still relatively large. In addition, we only use it to combat the symptom, not the cause, ”says Fuss. The same applies to artificial clouds or other ideas. Instead of relying on immature technologies to save the global climate, people have no choice but to emit less CO2.
More: A cooling screen for the earth would cost two billion euros