Climate change. It’s us. We’re sure. It’s bad. We’re building more wind turbines than ever, switching to electric cars and we all have a vegan cousin. But we're not making a dent. Some say we shouldn’t stand there and watch as the natural systems that sustain us start collapsing. They say we should engineer - or geoengineer - our way out of this mess. And they’ve figured out how to cool the planet back down. It’s so quick and cheap, we might just give it a go. What could possibly go wrong?

01. A clear and present danger.

A pristine forest covered most of this land, until we humans came in and set it on fire. We cleared parcels and grew crops. This worked for a few short years until we had exhausted the soil of its nutrients. Then we moved on to the next plot, leaving a desolate and sterile wake behind us. This was 5000 years ago, and it turned this place into what an 18th century observer described by a traveler as barren land dotted by “wretched hamlets” and farm animals of “very poor appearance”.

This place is under threat, again.

Our timing is perfect, of course. Before catching a local train back to Hamburg, we have time for "Kaffee und Kuchen", a warm drink served with a massive wedge of cream-filled cake - our substitute for sunshine over here in northern Germany. The place, an old barn restored to German comfort standards, marks the end of our hike. It sits on the edge of Germany’s first national park, the Lüneburger Heide. This afternoon I joined the local mountaineering club with a friend for a hike through Europe’s largest heathland. It’s a rough place. Not for the terrain - the summit stands at an impressively low 169 meters - but for the landscape. At the end of summer, the blooming heath turns a flashy pink. But not today. Today we absorb this desolate place in silence, white clouds carried by a fresh wind race across the awkward blue sky, alternating chilly shade and blazing sunshine every minute. Our eyes wander across the expanse of shrubby brownish-green heath, take anchor at each battered lone juniper tree and settle on the menacing pine forests on the horizon.

We’re fighting to preserve yesterday’s man-made environmental disaster.

This hot spot of romantic tourism is under threat. If it wasn’t for the devotion of the locals who graze their sheep here, for the volunteers who pull-out thousands of pine and birch tree saplings from the sandy soil each year or the controlled fires and land stripping of the park authority, the heath would be no more. An army of volunteers and millions of Euros is what it takes to protect this landscape from the besieging forests. We’re fighting to prevent trees from conquering this land. We’re fighting to preserve yesterday’s man-made environmental disaster.

This habit of ours.

We’ve been at it for a long time. But recently we’ve gotten even more skilled at wrecking our habitat and disrupting the extraordinarily complex and interconnected flows of minerals, microbes, plants and animals that sustain human life.

The list of assaults would read as a farce if it wasn’t revealing a tragedy. We’re driving species to extinction at rates hundreds or thousands of times higher than natural rates. We dump so much fertilizers on our fields that the runoffs kill oxygen breathing life - that’s algae, plankton, fish - in large patches of our oceans. There’s micro-plastic, air pollution, deforestation, defaced landscapes, mining sludge, nuclear waste, etcetera. Etcetera.

And then, there’s climate change.

A small part of the energy we receive from the sun - in the form of heat, visible and invisible light - gets trapped in our atmosphere. This works like a greenhouse and keeps the planet warm enough for life to flourish. The rest of the energy bounces off clouds, sea ice or continents, back into space where it doesn’t bother us anymore.

But, as you might have heard, we pump about fifty thousand million tons - that’s 5 kilograms, followed by 13 zeros - of greenhouse gases in the atmosphere each year. Each year, a little less of the energy that comes to us from the sun filters back out into space. That extra energy, because it heats our oceans and our atmosphere, is triggering instabilities in our climate system. Instabilities that we have never had to deal with since we became humans.

This year’s report by the Intergovernmental Panel on Climate Change - the IPCC is nothing less than the biggest peer reviewed scientific undertaking since the invention of science - is daunting to read and a breeze to summarize: climate change is real, we’re causing it and unless we change the way we do things by 2030, we might be in for bad surprises. If we continue on our current path, the global average surface temperature will very likely increase by 4.5°C by 2100. That's 4.5°C above what they where before the industrial revolution. My daughter will be 83 years old by then. Let’s not even look at the horror her children might face.

Show of hands: who’s optimistic?

And it sounds like the only solution we can find is the total annihilation of capitalism by mid-century. The overwhelming, uncontrolled, global, oil-fueled economic and social system on which 3.5 billion people still count on to improve their lives needs to be brought to its knees. Our emissions of greenhouse gases need to decline - tumble rather - even sooner, by 2030.

Sure, I’m never the optimistic one.

But that sounds ambitious.

They’re calling us “the last generation”, the one tasked with turning the ship around.

We’re told the survival of our species depends on the choices we make today. They’re calling us “the last generation”, the one tasked with turning the ship around. Very flattering, but I’ve never signed up for this. I don’t want life-or-death decision power on entire generations of human beings. Anyway, it's not compatible with me deciding that life’s purpose is to be enjoyed.

What now?

Some are working on geoengineering, a toolbox we could use to change our climate, deliberately this time. Geoengineering - sometimes called climate engineering - still sounds like Sci-Fi to me. Maybe because I haven’t been reading Sci-Fi. It could magically make our climate troubles go away. Not to mention, the guilt.

The contours of this toolbox are rough. But researchers and industries are testing geoengineering in the open already. They’re “seeding the ocean” off the coast of Chile, “spraying clouds” off eastern Australia or “injecting aerosols” in the stratosphere, 15 kilometers up above the heads of the Sami people.

Environmental NGOs aren’t convinced. They say the techno-fix doesn’t work, will make the whole mess even worse and will entrench global inequalities. They’re fine-tuning their petitions, mobilizing and calling for geoengineers to just keep their “hands off mother earth”.

Climate Engineering is described as “smart” and “essential”. Also, as “a clear and present danger.”

02. Today's Priority.

In 2015, after years of negotiations culminating in a week-long global summit sprint in Paris, world leaders took a leap of faith and demonstrated unprecedented political courage. They agreed to limit global warming to 2°C, on paper. The Paris Accord’s main achievement might have been to get climate activists and their detractors to agree on one point: the Paris Accord is just that, paper. No one backed up the good intentions with realistic plans or budgets. Our track record of coming together as a species to solve pressing global issues is not excellent. But we do have one.

Risk management.

Climate change is real. It’s man made. We’re sure. It’s bad. Going against the body of proof is self-delusional, manipulative, irrational or just plain stupid. For the past 33 years, the Intergovernmental Panel on Climate Change - the IPCC - has been compiling our collective scientific knowledge on the state of the climate. The latest report, published in the summer of 2021, condenses over 14000 independent scientific papers into a manageable format of a few thousand laconic pages. Hundreds of climatologists, meteorologists, oceanographers, ice formation or cloud specialists from 195 countries worked on the largest peer-reviewed scientific undertaking for 3 years. It doesn’t make for an entertaining read.

We need to cut our greenhouse gases emissions in two by 2050 and bring them to zero before 2075, if we want a reasonable chance of not warming our planet by more than 2°C.

The media water-cannon drenches us with news of floods, hurricanes and wildfires that are, apparently undoubtedly, marks of a warming planet. But the existential risk lay elsewhere. 2°C is not a safe limit. It’s the temperature increase above which scientists stop backing up their predictions. Their models do a good job at projecting what a warmer but predictable climate has in store for us, but they can’t predict freak events. We cannot rule out the rapid and complete dislocation of Arctic ice sheets or the sudden release of yet more warming gases from the Siberian tundra. These low likelihood, high-impact events would make us tip into a world we cannot start picturing.

The simple solution.

As far as problems of ungraspable magnitude go, Climate Change has a remarkably straightforward solution: emission reductions. We need to stop pumping more CO2 and other greenhouse gases into the atmosphere. In fact, we will bring our emissions of greenhouse gases to zero, or else. It is not a solution to unpredictable climate change; it is the solution.

As far as problems of ungraspable magnitude go, Climate Change has a remarkably straightforward solution: emission reductions.

Only one thing stands in our way. Capitalism. Over the past 200 years, extracting, transforming, transporting, selling and disposing natural resources has done us a lot of good, and harm. To bring our emissions to zero, we should stop that. Humans in the global north should realize money isn’t everything and find joy in lower living standards. Humans in the global south should recognize that the lifestyle globalization has been selling them for decades is a mirage. To make that work we would need a "re-engineering of human souls", to paraphrase Stalin.

Are we failing, or have we failed?

Recently, a team from University College London calculated how long the party could go on. They tallied our oil, coal and gas reserves and figured out how much we could still afford to pump and mine if we seriously tried to meet the Paris Accord target. 90% of our coal and 60% of our oil and gas reserves need to stay where they are today, underground. This sounds somewhat unlikely. Despite the sustainability speeches and the tear-jerking visions of a better tomorrow, no country has yet given up on exploiting their own natural resources for the good of humanity. Worse, they’re still investing, exploring and finding new reserves every day. They're not doing that to leave them where they found them.

Looking at our emissions gives us another hint. We want our greenhouse gas emissions to peak before the end of the decade, and tumble by at least 10% each year after that. They’re still growing year after year. 2020 gave us a sneak peek at what drastic emission reductions might feel like in real life, and at which social and human costs. COVID-19 lockdowns lead to an 8% emission reduction, for 3 months.

Climate change unfolds on scales that are hard to grasp. Models predict that by 2300 sea levels will rise anywhere from half a meter - which seems manageable - to more than 15m - which does not seem manageable. That’s a lot of long-term uncertainty for a human brain to handle. And climate change doesn’t give direct feedback, the type of feedback we’re good at processing. Sell your car, cancel that flight to go see your in-laws, go vegan and invest in solar panels and no one will notice. From our perspective, nothing you and I can do has any tangible impact on climate change. If the 7.5 billion of us magically stopped everything today, it would take at least 20 years for thermometers to register a dent in the temperature curves. Today, for most humans, climate change is a non-event.

Yesterday’s priority.

Sun screen gets in your eyes, inevitably. And when it does, it stings. Yet, I still use sunscreen. I know the sun’s rays are dangerous, because of the Ultra-Violets. When they penetrate living tissue - your skin - UV-Bs damage the molecular machines that keep your DNA in working order, leading to cancer. Most of these damaging rays never make it to earth's surface, where we spend most of our lives. They ricochet right back into space after hitting gas molecules made up of three oxygen atoms that act as tiny mirrors in the upper reaches of our atmosphere. That’s what we call the ozone layer.

In 1974, scientists in California and in the UK uncovered a chemical chain reaction that, over several years, ultimately destroys these ozone molecules. The chain reaction starts when humans release CFC gases into the air, which we used in our fridges or hair spray cans, when hair spray was still a thing. That discovery was awful news for CFC manufacturers and terrible news for humans who wanted to live a cancer-free life.

“perhaps the single most successful international agreement”

The industry was quick to react. It set up the usual public relations decoys, dismissing the findings as “a load of rubbish”. But, when 10 years later NASA’s brand new SAGE satellite and the British Antarctic Survey started measuring unusually low concentrations of ozone above the south pole, the world realized it had a hole in its ozone layer. Alarm bells were rung. Awareness was raised. Experts were summoned. Phone calls were placed and faxes were sent. Part of the science was still blurry. Still, after 18 short months of negotiations, the members of the United Nations agreed to phase out and ban ozone-depleting substances. Kofi Annan, the former UN Secretary General, described the Montreal Protocol as “perhaps the single most successful international agreement”. Since then, ozone levels have stabilized and everyone is still onboard.

This is outlandish. We humans faced an impeding ecological disaster, we cared enough to come together on a global scale - during the cold war - and agreed on a painful solution to a complex, long-term problem. We engineered our way out of an existential threat.

That was 1985. The urgency was the ozone layer.

Today the urgency is Greenland. Our failure to seriously tackle climate change has left us wondering if spraying sea water in the air from dingy boats might help against the melting of a kilometer-thick ice sheet that could raise sea levels by 7m.

03. Are we supposed to stay there and watch?

On July 28th 2021, a weather station near Ittoqqortoormiit recorded a temperature of 23.2°C. Warm enough to take the sandals out for a spin, not hot enough that I will break into a sweat just standing there. But the locals in Ittoqqortoormiit will tell you 23,2°C is too hot. Much too hot. They live a short 2000 kilometers from the North Pole, on Greenland’s east coast. Some climatologists think it’s time to unpack the last-resort ideas. The alarm bells we’ve been waiting for are ringing.

That’s not a weird, solitary fluke on the temperature curve. The artic region is warming even faster than what pessimistic climate models where telling us just a few years back. Average temperatures are more than 2°C higher than what they were before pre-industrial times. At the end of summer, artic ice covers only about a quarter of what it covered in the 1970s.

Always read the fine print.

Sea levels will continue to rise, that’s certain. We aren’t sure how much. In its 6th report, the Intergovernmental Panel on Climate Change gives sea level rise projections spanning between 50 cm and 1 m for 2100. Greenland’s melting ice sheets account for 10 cm of that. A study estimate that 630 million people - mostly in Southeast Asia - will see their livelihoods disappear by the end of the century because of rising ocean levels. Still, Greenland's slow disappearance will not unleash a rapid global catastrophe. Until you look at the details.

Gigatons of water are just part of the problem. The boundary between cold air from the artic and warmer air at lower latitudes is growing unstable. This leads to more frequent dangerous heat waves on the Pacific coast of North America, or torrential rains in Europe. Summer 2021 was just a preview.

The boundary between cold air from the artic and warmer air at lower latitudes is growing unstable.

Worse, a warming North Pole might trigger hidden tipping points by creating what scientists call positive feedback loops. We call them vicious - or virtuous - circles. Sea-ice is bright white. Like a mirror would, it reflects a lot of incoming sun light and heat back into space. But when sea-ice melts, it reveals dark - beautiful - waters which reflect a lot less light and absorb more heat. This melts more ice. Repeat the cycle a few times and you find yourself with an ice-free polar region by 2075. A warmer artic might also prime a feedback loop that could release vast quantities of carbon from Siberia’s permafrost. That frozen layer of rich soil holds twice as much carbon as the atmosphere does. A warmer arctic thaws permafrost, which releases greenhouse gases, which warms the arctic, which thaws more permafrost. A vicious circle.

These scenarios are unlikely. How unlikely? We don’t know yet. Because scientists don’t fully understand how ice sheets disintegrate, they can’t say if we’re pushing the climate system past a tipping point that would speed up everything. They cannot rule out that what we’re seeing today is the start of a rapid dislocation of our ice sheets, or not. But if we cross the tipping point, we might see levels rise by 1,5 m at the end of the century and 15 m within 200 years, changing the face of our planet within a few generations.

Let’s spray together.

Sir David King, a former Chief Scientific Advisor for the British government, thinks we don’t have the luxury of waiting for the likelihood and risks to be assessed accurately. That might take decades. What we already know is that a world with a colder arctic is a more stable world. So we should look at all options to keep our ice caps ice cold.

That’s what his teams at the Center for Climate Repair at Cambridge in the UK are doing. Marine Cloud Brightening - a.k.a. MCB - is just one idea they are toying with.

MCB, like other Solar Radiation Management methods, tries to raise the planet’s albedo. Albedo describes how earth - and other objects adrift in space - reflects light and energy back into space. A higher albedo means more energy is reflected out, exactly what we need right now. Picture a Metalhead on the brink of hyperthermia. As he takes off his black t-shirt and presents his milky white - sunscreen-protected - skin to the sun, he increases his own personal albedo. The planetary equivalent of that move would be to brighten and whiten the clouds above the arctic, cooling down the region and preserving the ice sheets.

MCB is ambitious and realistic. A fleet of autonomous solar and wind powered giant catamarans would roam the polar region, continuously spraying sea water in the air. Just as our Metalhead is not likely to die of heat exhaustion in the foggy highlands of Scotland, the water droplets would create a shading veil over the dark waters, reflecting more light and heat into space. This is new technology, but spraying water seems within reach of our civilizations. The major engineering hurdle is to make the droplets small enough for the artificial cloud to stay white, and not turn a menacing gray, in which case it would start absorbing more heat again. Surely we’ll find engineers to make the drops just as they should be if saving the artic and preventing runaway climate change is at stake.

“A slippery slope down the abyss.”

Real-world, out-in-the-open, trials of the method have started. Not off the coast of Greenland, but off the east coast of Australia. There, the Reef and Restauration and Adaptation Program is testing a pallet of last-ditch efforts to help the great barrier reef survive the next decade.

These open air tests are setting a precedent. A dangerous one. Many environmental protection organizations, such as ETC, the Climate justice Alliance or the Heinrich Böll Foundation, are saying these tests are illegal and need to be nipped in the bud. Great barrier reef or not, they warn that “dimming the sun through solar geoengineering poses extreme risks”.

Simply studying and talking about these geoengineering programs could create a fatal diversion.

Even Harvard’s Solar Geoengineering Research Program, which leads the way in Solar Radiation Management research, admits it. Simply studying and talking about these geoengineering programs could create a fatal diversion.

Humans act in mysterious ways. What will happen to the noble intentions? Who is going to continue reducing emissions if we catch just a hint of impression that, maybe, a conceivable technical fix to climate change exists? It doesn’t take much to imagine the worst polluting countries, companies and individuals hype the mere idea of geoengineering to throw away the sustainability PR slides and cement their interests. They’ve started already.

Recent research also shows that sustained solar geoengineering, even focused on a small region, will change how our environment works on a global scale. Climate models show that cooling down the US mid-west with a similar method as MCB, for example, will trigger a chain reaction leading to long-term warming of the artic - oh the irony - and changes in rain patterns across Asia.

Fundamentally, spraying water in the air from dingy boats to cool down a kilometer thick sheet of ice does nothing against the root of our climate problems. It works like opioid pain killers, making the pain go away, not the disease.

If we’ve pumped too much of these greenhouse gases into the atmosphere and oceans, can we not suck them out again? That sounds like a cure.

04. Pulling carbon out of thin air.

The problem is that we’re pumping too much greenhouse gases, like CO2 - carbon dioxide -, into the atmosphere. Surely someone has thought about how we could capture it from the air, store it in a safe place, and forget about it. That’s not impossible. Imagine you’ve just made laundry for 125 people. Picture their socks in a pile and then multiply that by 1000. Now imagine you’re looking for that one missing spotty sock your three year old absolutely insists on wearing today. Capturing CO2 out of thin air is like that. It requires sieving through a lot of air, because only one out of 2500 molecules in our atmosphere is CO2. Some people - whose morale has obviously never been dampened by sorting piles of socks - have been thinking about ways to do that.

Using cogs and wheels.

Climeworks, a startup based in Switzerland, opened the first industrial scale Direct-Air-Capture facility for Carbon Dioxide Reduction - CDR - at the end of Summer 2021. Their Icelandic plant, a.k.a. Orca, is powered by carbon-free geothermal energy. It sucks in - a lot of - air through four banks of industrial scale ventilators, sieves out part of the CO2 and injects it underground. There the CO2 reacts with minerals and solidifies as Calcium Carbonates. Once in solid form, the carbon is sequestered for ever. Excellent. The whole setup could sequester 4000 tons of CO2 every year. That comes down to taking 1000 cars off the road, with an optimistic tally. All we need now is capital, suitable storage rock formations and carbon-neutral power plants to build 15 million other Orcas - give or take - to absorb the CO2 we’re adding to the atmosphere.

The whole setup could sequester 4000 tons of CO2 every year. That comes down to taking 1000 cars off the road.

The most tricky part is the storage. We want the gases to stay put below ground, and this asks for the right rock formations. Luckily, big oil is on the case and helping to develop CCS - Carbon Capture and Storage -. They’ve been greenwashing their way to corporate heaven by developing these storage technologies, injecting CO2 down old oil and gas wells. Not for karma, but for Enhanced Oil Recovery. The business plan is easy: pump oil, ship it to consumers who burn it, absorb part of the resulting CO2, inject it below ground to pump out yet more oil. Make profit at every step of the process and issue tear jerking PR statements on your unprecedented efforts to save humanity. Environmentalists have looked into it. They have doubts.

Using trees.

A healthy patch of forest, 2 kilometers a side, captures as much carbon as Climework’s Orca plant. After all, trees are mostly made of carbon sucked out from the air through photosynthesis, and life rich soils are effective carbon sinks. Researchers from The Nature Conservancy, a global environmental organization, estimate that at least a third of the emission reductions we need to materialize before 2030 could come from preserving and restoring natural environments, especially forest and peat land.

That only helps if the carbon has no chance to escape for a few thousand years. Chopping down the carefully maintained forest or drying up the peat land, send the entire carbon store up in the atmosphere again. The IPCC - the International Panel on Climate Change - is highly confident humans cannot be trusted to preserve forests for a few dozens years, let alone for millennia. Taking care of our forests makes a difference, but only a small one.

... would using both work?

The next acronym on the list of CDR methods is pronounced “beeks” and written BECCS. It stands for Bio Energy with Carbon Capture and Storage, and combines the best of both approaches: capturing CO2 with natural processes, storing it with smart engineering. If we grow trees on an industrial scale, chop them down, burn them to produce electricity, capture the CO2 before it leaks out into the atmosphere, and bury it deep below our feet in stable storage, we produce electricity and sequester greenhouse gases. A win-win deal if I ever saw one.

Of course, BECCS forests look nothing like lush forests. Rather, it’s a tree-after-tree, lined-up-as-far-as-you-can-see type of forest. And our track record at managing industrial plantations is not great. They run on ultra cheap labor, displace small scale subsistence farmers, replace wilder forests and compete with cropland, all for the benefit of a few landowners. A landscape or business no one wants in their own backyard. Anyhow, plantations are not good at capturing carbon in the first place, they absorb a fraction of the greenhouse gases compared to the natural ecosystems they replace.

We’ll use rocks, then.

Smarter people haven’t been waiting for me to write these lines to spot the dead end. A dozen more creative ideas are looking to strike a good enough compromise between social justice, environmental impact, cost effectiveness, long-term climate effectiveness and the laws of physics.

Ocean Fertilization was our champion. It’s a human attempt at mimicking how winds pick up sand from the Sahara and disperse it over the Atlantic ocean. This fertilizes the ecosystems at the ocean’s surface and boosts plankton growth. When the micro-organisms, or the fish that eat them, die, they slowly trickle to the bottom of the ocean, taking the carbon that make up their cells with them. We’ve dumped iron powder off the coast of Chile hoping to replicate the system, with a devastating impact on local environments.

Ocean Fertilization is a human attempt at mimicking how winds pick up sand from the Sahara and disperse it over the Atlantic ocean.

On land, researchers in the UK, Canada or Australia are fitting crop fields with hygrometers and other sensors to understand how Enhanced Weathering could boost the soil’s capacity to absorb CO2, and improve yields. Crushed volcanic rocks, when spread on the crop fields, would react with water and carbon in the soil to form bicarbonates. Rain washes away the minerals which should end up on the ocean floor as well. This method could offset half of agriculture’s annual emissions, if we used it on every square meter of cropland on the planet. Research is ongoing to understand if the trick will work year in year out, what the impact of mining all these minerals is and if we have enough of the stuff to make this a realistic option.

We'll use everything we can.

Direct-Air-Capture seems like a stretch, afforestation won’t save us, BECCS is worse, CCS and Enhanced Weathering are still experimental.

At the same time, when climatologists run their models, they cannot plot a course between today and a world that suffers less than 1,5°C warming in 2100 without CDR. Most realistic scenarios plotting the course towards a 2°C warmer world also count on us developing functioning CDR technologies. As an example, the UK’s emissions reduction plan asks for the country to deploy an as of yet unknown technology to pull millions of tons of CO2 from the atmosphere in the next decades.

The question is not “should we suck CO2 out of thin air?”; the question is “how fast can we get any of these options to work?”. Because we will need all of them, even the ones big oil is working on.

And while we won’t be able to trap all the gases we emit today with CDR, these geoengineering methods might help us on the last stretch. They could help compensate for the left-over 10% of emission that are too expensive or impractical to cut at the source.

Fortunately, we might not need to bother with CDR. We’ve found a way to cool the planet back down within 5 years, for cheap.

05. We can cool the planet in 5 years.

On April 10th 1815, mount Tambora blew up. The largest volcanic eruption on record obliterated the 4300 meter high volcano on Sumbawa island, one of Indonesia’s 13000 or so islands. It sent 150 cubic kilometers - the volume of 30 billion average elephants - of exploded rock and ash in a column, 43 kilometer high, that reached the upper reaches of the stratosphere. Ash fell 1300km from the volcano. On Sumatra, 2600 kilometers away, observers noticed the sounds of distant explosions. Over 10 thousand people died instantly.

Using the latest generation of climate models - software simulations of our climate, running on supercomputers - scientists confirmed what they had suspected. The eruption triggered a planetary cooling event, with global average temperatures dropping by 0,5°C the following year. The dust and sulfur particles propelled high in the stratosphere created a veil, reflecting a little more sunlight back into space than usual, and cooling the planet.

If a volcano can cool the earth, we humans can do it too. The logic is foolproof.

Mimicking a volcano.

According to the IPCC - the scientific panel that compiles our knowledge on climate change - we could, with an “aggressive Stratospheric Aerosol Injection campaign”, build a volcano-like veil and bring average temperatures back to what they were in 1900 within 5 years. We’ve been testing this idea, by accident. Cargo ships run on the cheapest fuel possible. As they make their way across the globe, they spew sulfur and other polluting particles in the air, creating a shading veil that keeps our planet about 0,25°C cooler than it would normally be. How ironic.

Stratospheric Aerosol Injection - SAI - would be an attempt at mimicking mount Tambora and tweaking our climate, purposely this time. Long-winged airplanes, similar to the high-flying U2 spy planes of the cold war, or atmospheric balloons would climb to the stratosphere, a relatively stable layer of our atmosphere that starts 11 kilometers above our heads. Up there, where the curvature of earth becomes visible and the blackness of space starts taking over, they would spray sulfuric gases - or other particles that are less damaging to the ozone layer. Tiny diamonds, for example. - by the ton. Resembling the ashes of mount Tambora, the particles would reflect more incoming light from the sun back into space, before it could reach - and warm - the lower atmosphere.

Stratospheric Aerosol Injection would be an attempt at mimicking mount Tambora and tweaking our climate, purposely this time.

Stratospheric Aerosol Injection could herald a new world order. A window of opportunity is opening for the global north, who has been the virtual sole contributor to climate change until today. It could be time for a noble endeavor, to cool the planet just in time to spare the countries which have not contributed to climate change - and have little means to adapt to it - the worst consequences of runaway climate change. Just as well, SAI could turn into an instrument of domination, where rich economies would inject more and more sulfur to balance out whatever they are doing today to stay on top, reinforcing global inequalities.

He who controls the means of spraying.

Chester Dewey, professor of Mathematics and Natural Philosophy in Massachusetts, noted “severe frost” in his weather log on August 29th. It had snowed on June 6th and frozen on June 8th, 10th, July 8th and August 22nd. He notes “very little Indian corn became ripe in the region”, with more than a quarter of the harvest lost. The spring and summer of 1816 had been unusually wet and cold. Further up north, in Quebec, people ran out of bread and milk. In Europe, the price of grain doubled between 1815 and 1817, leading to the last western European famine. Wheat, oat, and potato harvests failed in Ireland as waves of hunger riots, looting and migration swept the continent. In Asia, the monsoons season was disrupted, leading to floods in China and cholera outbreaks in India.

The Tambora eruption, rapidly cooling our climate by a mere 0,5°C, set out a chain reaction that sent devastating ripples across the northern hemisphere. What ripples would a man-made veil, trying to make up for a 2°C warming world, send around the globe? What world would a veil to compensate for 4°C create? We don’t know exactly. We’ve never tested. The consequences would not be imperceptible.

And while Stratospheric Aerosol Injection is not a weapon - it’s not precise enough to be one -, he or she who controls the means of spraying will certainly gain an unprecedented level of power to advance his or her strategic interests.

A very different planet.

Any how, Solar Radiation Management - SRM, a set of veiling methods which includes SAI or Marine Cloud Brightening - cannot “solve climate change”.

It works by cloaking the greenhouse gases we’ve released into the atmosphere, not by disposing of them. SRM is not a reset button. It would create a new version of our climate, not bring us back to the way it was. For the same reason, SRM has no positive effect on ocean acidification - one of the major symptoms of our changing climate system - and how it impacts biodiversity.

A geo-engineered planet will be cooler. It will be a planet with different rain and wind patterns, and a very different biosphere. Also, it will come with extra responsibilities.

Termination shock.

The stratosphere is stable compared to other layers of our atmosphere. But the reflective particles used in SAI will only stay there in suspension for a few months before trickling back down to the ground. To make up for lost particles and adjust the cooling effect, we will have to renew and sustain the veil continuously, century after century. Like opioids, Stratospheric Aerosol Injection would make the debilitating pain go away. Like opioids, it could get us addicted to the point of self destruction.

Termination shock is a problem. A big problem. A colossal problem.

Once we veil our planet, if we continue accumulating greenhouse gases in the air, we’ll need to build a stronger and stronger veil to compensate for the ever increasing warming effects. If we stop spraying more particles - Absent-mindedness? War? Extinction? Short-sighted leaders? - the cooling effect dies out in a matter of months. Losing their cloaks, the excess greenhouse gases start expressing their full warming effect, triggering global warming so rapidly it would make our current problems look manageable. Proponents of solar geoengineering call this the termination problem. Others, wanting to stick closer to reality, call it the termination shock. Realistically, life would not survive. Once we start with SAI, we’re committed to it until we can pump out enough CO2 from the atmosphere. That might take centuries.

Termination shock is a problem. A big problem. A colossal problem. For most anti-geoengineering activists it justifies shelving the plans altogether, today, because ignorance is bliss.

Can it not happen?

New technologies and research areas are powerful memes, especially when they hold immense potential to cement - or threaten - the interests of the powerful. They will be researched, tested, and deployed. Geoengineering has been grabbing attentions at both extremes of the activist scale: mother-earth-loving-hippies see the dangers in deploying it, they see the injustices, the never ending problems of history repeating itself. The military see the same. Even if geoengineering cannot be weaponized, it has the potential to unleash global change and human suffering. The US and China are running research programs on Solar Radiation Management, because ignorance is not bliss. They won’t keep their hands off these shiny new toys.

And as far as global climate-altering operations go, Stratospheric Aerosol Injection comes in cheap. Ridiculously so. Estimates put the costs of cooling down our entire planet at a few billions of dollars each year. A tenth of what we spend on pet food. That’s cheap enough for a small state, frustrated with global negotiations, to go rogue with its own fleet of sulfur spraying airplanes. Cheap enough for a visionary billionaire eyeing a spot in the history books, once the thrill of riding his metallic phallus to the edge of space has faded.

06. This isn't fun.

Were our ancestors right? Was is OK for them to burn down the lush forests that once covered the Lünerburger Heide plot after plot, to feed themselves? There are many answers to that question. They were Humans looking for solutions to their human problems - hunger - with the human solutions they had. Clearing the forest must have felt appropriate. Today, we choose to preserve that environmental disaster, protecting it from invading forests. The next generations live with the consequences and grudgingly look for solutions to their own problems.

I had no opinion on geoengineering before this essay. Or rather, I had several opinions. The degrowth hippie inside me was searching for another opportunity to denounce our folly. My techno-optimist side was looking for a fix that would make climate change go away.

No one is happily looking forward to a geoengineered mess of a planet.

What I’ve found is that trumpeting geoengineering as a solution to climate change takes a decent level of self-delusion. At best, it could ease the pain. Refusing the mere idea of discussing geoengineering doesn’t make much more sense. Either climate change is the biggest threat humanity has ever faced, and in that case we need to look at every option, or it’s not.

I’ve also found that no one is happily looking forward to a geoengineered mess of a planet. There’s no fun in it. Those researching the field are trying to repeat what has worked for us in the past 300,000 years, reluctantly solving man-made problems - this time it’s about preserving dignity, for as many of our descendants as possible - with the man-made solutions. What else can we do?

We need nuance.

I haven’t found a simple solution. Instead I found a tremendous, magnificent, man-made mess. As I looked down into the abyss of a geoengineered planet, I started seeing the finer details, the competing angles, the more nuanced opinions, the lost causes and the absurd promises. Geoengineering is no monolith. There are methods to suck out greenhouse gases from the air, plans to cool down entire regions and ideas to reflect sunlight back into space. Some ideas seem wacky to me - I haven’t mentioned the idea of farming asteroids around the first Lagrange point - and others seem plain obvious - plant trees! -.

I’ve found that we need to look closer still. A recent study shows how geoengineering a colder US mid-west disrupts rain patterns in Asia and even warms the arctic. That study also shows that cooling down the same region punctually, only to ease the pain of intense summer heat waves, would have little or no negative impacts. Other studies show that large scale Stratospheric Aerosol Injection to compensate for a 2°C warming world will lead to some sort of climate mayhem. But a less ruthless objective, one that would aim to cloak only half of our emissions, might not have serious effects. If we look closer, we still won’t find a simple solution, but we might find something less risky, more consensual and useful. Something that might help us make it through the next decades.

I’ve also found that everyone, however they might feel about repairing our climate, agrees about reducing greenhouse gas emissions. Geoengineering or not, all the sane minds know we will only avoid the worst impacts of climate change by bringing our emissions to zero in the second half of the century.

This is not comfortable.

How do sulfur particles behave in the stratosphere? Will spraying water in the air cool Greenland’s ice sheets? Does Enhanced Soil Weathering have side effects? We don’t have precise answers to those questions, and many others.

We don’t get to choose between the planet as it was 200 years ago and a geoengineered nightmare; we get to choose between a planet with climate change and a geoengineered planet with climate change. Which one holds a better future for most Humans? The answer depends on how much trust you put in our collective intelligence, and on how much time we give researchers to collect more facts.

They’re not moving fast, because research projects run by the Center for Climate Repair at Cambridge, Harvard’s Solar Geoengineering Research Program or the GeoMIP project - to name a few - capture less than 0,3% of our energy related research and development budgets. And we still haven’t agreed on how to frame, control and allow - or outright ban - geoengineering research, development and deployment. We can’t even agree on which global forum is appropriate to discuss this.

We don’t get to choose between the planet as it was 200 years ago and a geoengineered nightmare; we get to choose between a planet with climate change and a geoengineered planet with climate change.

And so today, we’re smoothly heading towards the catastrophic scenario. One where someone, somewhere, because social pressure is mounting, decides, unilaterally, to have a go at geoengineering before the research is in. This is the risk of geoengineering, today.

We can make it work.

We still have time to assemble a more solid web of scientific evidence. We know what research needs to be done. We can still decide to build an inclusive and transparent structure to decide if and how we want to use climate repair. There are proposals on how to make that happen.

What we need is political courage, good science and open discussions.

The Keutsch group at Harvard is at the forefront of Stratospheric Aerosol Injection research. They want to understand what happens when we spray particles in the stratosphere, not in their lab. Their SCoPEx experiment - Stratospheric Controlled Perturbation Experiment - sees a high-altitude balloon release up to 2kg of dust 20km up above northern Sweden. By analyzing the kilometer long dust plume, the scientists want to understand how the particles reflect incoming sunlight, how they spread out and interact with the other molecules in the atmosphere. Knowledge we need. Activists at the Hands Off Mother Earth campaign say this small experiment is enough to take the focus away from emission reductions. They suspiciously point at one supporter of SCoPEx, who happens to sit on the board of a company which counts oil companies as investors. They also see proof that geoengineering’s purpose is to cement established interests in the research team’s violation of local Sami rights to know and decide the fate of their indigenous land, water and air.

The experiment was called off in March 2021.

No data collected. No knowledge amassed.

No sign of political courage, good science and open discussions yet.

If you've made it this far, you rock. Thank you for dedicating some of your brain power on this complex topic. I've written this piece sitting in Hamburg in October 2021. See all my sources and reach out to me or see if I've written anything else that you might find interesting. Let me know what you want to read next.

/ Xavier

©️ Xavier Auclert