Will we cloud the sun, eat synthetic meat or reintroduce the mammoth?

Climate Pioneers No 9

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Dear Climate Pioneers

Can and should we engineer climate to cool down the Earth? In this number we explore:

  • Solar geoengineering: Reflect sunlight to control the temperature

  • Knowledge snack: Albedo – the mirroring effect

  • How they do it: “Will we still need synthetic meat by then?” (Interview with Dörte Bachmann, Sustainability Manager of SV Group)

  • Best pick: A movie about bringing back the mammoth

  • Future fantasy: The Gashole

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Thank you!


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Solar geoengineering: Will we have to cloud the sun?

Every year we emit billions of tons of CO2 into the atmosphere. The results of this experiment are in: it gets warmer. The question is, can we reverse engineer global warming? A story about solar geoengineering. In bullet points:

  • Solar geoengineering is the possibility to reflect a small fraction of sunlight back into space to lower temperatures on Earth.

  • Scattering aerosols in the stratosphere seems to be the most promising method to reflect the radiation.

  • Volcano eruptions in the past have shown that large amounts of sulfur aerosols in the stratosphere have a cooling effect.

  • Solar geoengineering cannot replace existing climate action, simulations suggest that it won’t work if GHG emissions go up.

  • Opponents point out that solar geoengineering distracts from reducing GHG emissions and could make everything much worse.

  • Solar geoengineering not only needs more research, but also a broader public discussion. Preferably before it needs to be deployed.

Let’s dive in. The basic idea of solar geoengineering is to protect the earth from sunlight. The more sunlight enters a greenhouse, the warmer it will get inside. The solution? Filter the amount of sun hitting the earth. Before we get into the how, let's look at why this crazy idea could even be considered appropriate.

Cutting emissions is not going to cut it, we might also need to engineer the temperature

World leaders signed many climate agreements in the past decades, yet global annual carbon emissions continue to increase. It seems existing measures are simply not efficient. Therefore Joseph E. Aldy and Richard Zeckhauser propose a 3-prong approach (a prong is the pointy part of the fork): GHG Mitigation + Adaptation + Solar Geoengineering. The authors use politicians to illustrate the concept:

  • Trump was a 0-prong player: he did nothing but deny climate change.

  • Al Gore was a 1-prong player: he focused on GHG Mitigation (reducing emissions).

  • Obama was a 2-prong player: he wanted both, GHG Mitigation + Adaptation (reducing emissions and preparing for impacts).

  • Yang is a 3-prong player: he promotes GHG Mitigation + Adaptation + Solar Geoengineering (reducing emissions, preparing impacts and controlling temperature).

The 3-prong approach includes GHG Mitigation, Solar Radiation Management and Adaptation to counter emissions, control temperature and prepare for impacts (Figure: J. Aldy and R. Zeckhauser).

In this perspective, climate action is much like a swiss knife: Use the blade to cut emissions and other tools to adapt to the changing climate and control temperatures. Each of the three strategies help in the fight against climate change. In fact, simulations suggest solar geoengineering will not work if GHG emissions keep increasing. But, the tools can also compete with each other, just one reason why it is difficult to bring solar geoengineering to the table. More on the risks later.

Knowledge snack: The albedo effect

The albedo measures the reflectivity of surfaces. Bright surfaces have a high albedo and dark surfaces have a low albedo. Snow reflects sunlight better than dense forest. Light surfaces have a cooling effect, dark surfaces absorb heat.

Now, let's get into solar geoengineering, often also referred to as solar radiation management or modification (SRM). How exactly would it work?

Scattering reflective aerosols is the most promising method to reflect a small amount of radiation back into space

Scientist propose four solar geoengineering methods in total:

  1. Cirrus cloud thinning: thinning or removing cirrus clouds to reduce their heat trapping capacity.

  2. Marine cloud brightening: evaporating spray of sea water microdroplets from ships traversing the ocean.

  3. Space-based techniques: positioning sun shields in space.

  4. Stratospheric aerosol scattering: introducing tiny reflective particles into the stratosphere.

According to professor David Keith the last one, scattering sulfate aerosols, is the most feasible and promising method. Why? Because it already happened.

In 1991 the eruption of Mt. Pinatubo in the Philippines injected vast quantities of sulfate aerosol particles into the stratosphere and reduced Earth's average global temperature by about 0.5 degrees Celsius (Image: Dave Harlow, USGS).

Solar geoengineering could be done with a modified fleet of aircraft and a few billion dollars

Another advantage is the technical feasibility. All you need is a fleet of modified aircraft and 2 million tons of sulfur. Plus, it's also relatively cheap to spray the aerosols into the stratosphere. People have estimated a few billion dollars for the aircraft fleet and the material. It can be redone every one or two years for the cost of ~1 billion dollar.

”We could, with solar geoengineering, keep temperatures under 1.5°C with confidence and we could prevent the loss of the major ice sheets and keep the Arctic more the way it is. I think that is pretty high-value thing!" David Keith

Moral hazard and termination shocks: Will solar geoengineering make everything worse?

On the other side, there are multiple known risks. The low barriers could pose a moral hazard, meaning if we know solar geoengineering works and can be done cheaply it could reduce incentives to cut GHG emissions and distract us from “real” solutions.

Another concern is that we will be depending on solar geoengineering for a long time or else risk a termination shock: if SRM stopped suddenly it could cause a sharp temperature increase and have reverse and more damaging effects than what would have occurred without it.

Major doubts belong to the weather effects: Will solar geoengineering create new winners and losers? Who will control the temperature switch? This and many more questions need to be discussed and researched.

Solar geoengineering needs more research and involvement, easier said than done

Earlier this month a balloon test flight was cancelled due to pressure from locals and opponents. The public in general is skeptical of geoengineering. So perhaps most importantly solar geoengineering must continue to build understanding of its risks and opportunities.

To sum up: solar geoengineering is the possibility to reflect a small fraction of sunlight back into space and lower temperatures. Solar geoengineering does not replace reducing emissions (mitigation) and preparing for impacts (adaptation), but it might be a potential supplement.

Everyone wants a blue sky, but in the case we don’t have the choice to deploy solar geoengineering, it would be great if we sorted all the necessary questions beforehand.

How do you feel about it?


The “How they do it” section explores how businesses are tackling climate change

How they do it: “I am wondering if we still need synthetic meat by then”

SV Group is a swiss-based hospitality management group with over 7000 employees. Their Sustainability Manager Dörte Bachmann shares how the group is taking climate action and is reducing their carbon footprint.

Do you think we will all soon be eating synthetic meat as Bill Gates is suggesting in his new book?
Dörte Bachmann: As Bill Gates writes in his book, synthetic meat (i.e. cell-based meat) is still very expensive and we won't find it on our shelves until the mid-2020s. However, I already perceive an increasing awareness of the impact of food on climate change. People care about the origin of the food they eat and more and more people want to change their diet by eating less meat. Plant-based meat is an already available and promising alternative to meat from animals. The quality and diversity of the products is continuously improving and demand for plant-based meat is increasing. I'd rather think that we will soon eat plant-based meat more regularly than cell-based meat. Plant-based meat is kind of a vehicle for the transition from a meat-heavy to a plant-rich diet. It helps to eat more plant-based without much changing your behavior. Once people are used to eating less meat, they will also try out new recipes without meat-alternatives but with a variety of vegetables, pulses and crops. I am wondering if we still need synthetic meat by then. Nevertheless, if the production of synthetic meat is more efficient later on, why shouldn't we include a small share of synthetic meat into our diet?! The recommendations from the EAT-Lancet commission summarize very well how a so called planetary health diet could look like. All food products, including meat, are allowed, but only in an amount that is healthy for the planet and us.

Organizations talk about aligning economic and environmental targets, have you found the secret and what is it for your company?
Dörte Bachmann: Together with our partner WWF Switzerland, we have set ambitious targets to reduce our Scope 3 CO2eq emissions. As we all need to eat and we don't have to relinquish a delicious meal, eating more plant-based dishes would have the highest impact to reach both our economic and environmental targets.

What are the main uncertainties related to the sustainability goals?
Dörte Bachmann: Though the awareness of the impact of food on climate change is growing, many of our guests still choose dishes with meat. However, to make the plant-based choice the easy choice, we train our staff to improve their vegetarian cooking skills and we continuously increase the share of vegetarian and vegan meals offered. We have also implemented many other measures in our operations such as reducing food waste to a minimum. Furthermore, we have established very efficient supply chain management and we purchase seasonal food. We measure our CO2eq emissions on an annual basis, but I would love to provide more transparency of the carbon footprint of each menu for our guests. Unfortunately, due to Corona that project has to wait a little longer.

Anything else you would like to share?
Dörte Bachmann: Well, I often notice that people are overwhelmed by all the global issues we are facing and the things we could do better. In regard to a sustainable diet, I think we can already do a lot if we focus on two main actions: eating less animal proteins and reducing food waste. Instead of worrying too much, we could start with these two easy, but impactful actions.


Would you like to feature the efforts of your organisation? Please answer four questions.

The “Best pick” section present a selected article, podcast, video or other resources

Best pick: Father and son make Siberia ready for mammoths

There is more coverage of Sergei and Nikita Zimov on Youtube. Hat tip to Eli Dourado for this finding.

Take the quiz

The “Future fantasy” section provides a fictional short story from the future

Future fantasy: The Gashole

30.04.2102 – Much of the 21st century was dedicated to reducing and removing emissions. Only with limited success.

The carbon sequestration and storage solutions were just not efficient enough to perform the required removals in time. Climate technology didn’t scale as expected. Many large-scale carbon capture operations rolled out and were running for decades without meaningful results.

It seemed all possibilities had been exhausted. That was the moment to turn everything upside down. “What if instead of drawing down greenhouse gasses from the atmosphere back to earth, they were released into space?”

The question almost seemed too stupid. Pretty soon researchers acknowledged it should work in theory. The Chinese space army was the first to shoot chemical rockets to the skies to pin a hole into the layers of the atmosphere. The final breakthrough of the air tunnel followed today.

The ‘Gashole’ is leading greenhouse gasses from the troposphere, stratosphere, mesosphere and thermosphere to the exosphere and solar winds. The valve works. And a kind of space zipper for regulation is also put into place. But the development brings the climate change conversation to a new level.

Interplanetary panels are discussing the impact on each other's systems and the exchange of resources. And the public debate has already been on fire for several months. One idea is to create dedicated roles for each of the planets: a planet for food production, a planet for mining, a planet for living. And so on. The planning approaches are countered by the argument that interplanetary systems would “work best when governments would leave them alone”.

The Gashole seems to solve one problem, but create new ones.


In the next issue

A main story, a Knowledge snack, How they do it, a Best pick and another Future fantasy will wait for you. Subscribe now, if you want to receive the next issue, access the entire archive and draft notes. Together we can help reverse climate change.

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About Climate Pioneers

Climate Pioneers is a monthly magazine. Readers receive findings at the intersection of business, science and sustainability. By the way, the footprint of this publication is removed via soil carbon certificate.

My name is Sam. As a teenager I really wanted to get away from the farm I grew up on. So I worked, studied and travelled in over forty countries. Only to come back and run a startup for meat from organic family farms. In 2019 I started Project Oasis with the idea to promote land restoration and carbon removal. The research and insights from talking to farmers and sustainability professionals emerged into this online magazine about climate solutions.