The North Pole and the South Pole can be placed in an artificial deep freeze by spraying sulfur compounds by tanker aircraft miles into the air each spring. It’s technically possible and the cost isn’t too bad, according to new research. This does not change the fact that there are also many disadvantages to the plan. And an important advantage.
The melting of permafrost, ice caps and sea ice can be completely stopped with solar-reflecting sulfur compounds, a group of American researchers writes in a journal Environmental Research Communication.
This would require a fleet of newly designed tanker aircraft capable of reaching an altitude of 20 kilometers. These planes would circle the Arctic Circles at the beginning of the summer to disperse the cooling sulphur. Estimated cost: 11 billion euros per year.
To be clear, this polar rescue plan is not underway, and it won’t be for a while. “We are only investigating whether it would be possible to cool the Earth’s polar regions again,” lead author Wake Smith of Yale and Harvard University told NU.nl.
Climate change is getting worse
The underlying reason is the seriousness of the climate problem. Heat waves and droughts are increasing and the ice caps are melting. The North Sea can also rise many meters in the long term. There are also tipping points: climate change may become (partially) irreversible or accelerate itself.
To be on the safe side, the heating should stay below 1.5 degrees. This means that global greenhouse gas emissions must be halved in eight years and be net zero twenty years later.
Artworks to offset emissions and warming
There are also alternative ideas to stop global warming, often referred to as ‘geoengineering’. The aim is not to reduce emissions, but to compensate for the emissions or the resulting warming. For example, with techniques to remove CO2 from the air.
Or by compensating for the heating itself, by ‘creating cooling’. This can be done by making the earth’s surface lighter in color so that more sunlight is reflected back into space and the temperature drops. You can feel the difference if you park a white car and a black car next to each other in the sun. The black car gets boiling hot, the white one stays cool.
Cooling the earth by mimicking volcanoes
But how do you make the earth as a whole (a little) lighter? A long-held idea is to try this not on the surface of the earth, but at more than 10 kilometers high in the stratosphere.
This is a calm layer of air, higher than most clouds and therefore also above the precipitation. This means that small dust particles do not fall straight back down, but can float around for months to several years. If these particles are bright, they reflect sunlight and cool the earth.
This was not invented by clever inventors, but copied from volcanic eruptions. They can bring a lot of sulfur dioxide into the stratosphere. This then forms bright ice crystals. And the liquid white crystals can cool Earth’s climate for a year or two after a major volcanic eruption.
As soon as you stop cooling, the temperature skyrockets
If one permanently mimics such a volcanic eruption, by bringing sulfur dioxide into the stratosphere by tanker aircraft, the warming of greenhouse gases can be reversed. So temporarily. Because as soon as you stopped taking it for any reason, the temperature would skyrocket again in no time. (And such rapid temperature swings are potentially extra harmful.)
In any case, the climate problem cannot be solved completely with this. If CO2 emissions are not also reduced, for example the acidification of the oceans (by dissolving CO2 in the oceans) will become increasingly serious.
Additional sulfur dioxide can also damage the ozone layer. And the closer the solar filter becomes, the more strongly life on the Earth’s surface is affected. For example, a decrease in solar radiation can have consequences for plants and animals. And the sky will no longer be clear blue. Finally, all kinds of water bed effects that are not known in advance can occur, such as disruption of rainfall patterns.
Reflection of sunlight on the poles is only possible in summer, in winter it is permanent night.
Local application at poles is more manageable
So lots of downsides and uncertainties. But what if you only did it locally, the researchers wondered, specifically at the poles? They warm up the most, which in turn has dramatic consequences for the rest of the globe.
In addition, the air flow in the stratosphere moves towards the poles. Locally dispersed sulfur compounds would therefore largely remain in the Arctic. “You might be able to try it for a summer season and stop pretty easily if you experience any adverse effects,” says Smith.
He also expects that the cooling of the poles will also extract heat from other areas of the Earth, and that the cooling effect will therefore be partly global.
The ozone layer is most vulnerable over the poles in early spring. According to Smith, ozone damage can therefore be prevented by first spreading sulfur dioxide later in the spring, or choosing calcium carbonate, which does not lead to ozone depletion.
What damage is the least acceptable?
But then we haven’t discussed one final downside of geoengineering: that it could give a false sense of security that climate change can shortcut could be solved without stopping the use of fossil fuels. This idea could potentially undermine support for existing climate policy through emissions reductions. It makes even writing about this research a moral dilemma.
But what if we continue with climate policy, but it doesn’t go fast enough because of wars, conflicting interests and a continued dependence on coal, oil and gas?
Even if there is peace in the world and there is cooperation for a sustainable global economy, large parts of Greenland’s and Antarctica’s ice sheets may still begin to melt, which may last for thousands of years and can no longer be stopped with emission reductions. In such a case, you might want a planetary plan B.
“Idyllic and sensible scenarios exist for the future of our planet,” Smith concludes. “But the Paris Agreement could also be a success that comes too late, so that global warming becomes unacceptable.” And then the damage from intervention may be less than the damage from many meters of sea level rise and all the other consequences of a warming of more than 2 degrees.