Warning this article is for people who actually believe climate change is a thing. If you don’t believe in climate change you might find this disturbing. As you also should find climate change disturbing.

Climate engineering, also called geoengineering, means engineering technologies to influence the climate. Imagine yourself getting fever: you go to the doctor, he gives you medicine, you get better. The idea with climate engineering is similar. The climate is changing. We keep doing things that drive that change, so maybe we should develop some medicine to treat it. Pharmacy drugs need to be evaluated carefully for their side effects before market entry and even then, the consumer can still decide whether he wants to risk potential harm for healing. However, a medicine applied to the climate could harm 10⁶’s of innocent human beings.

In this article I want to summarize some key learnings about geoengineering technologies and their societal treatment from a discussion we had with two leading experts, Dr. Wil Burns (American University) and Dr. Jason Blackstock (University College London), on www.letsmakethefuture.com. You can listen to the full discussion here.

But why should I read this?

Today’s world has one major method for fighting a global increase in temperature: making it increase less. This gets media coverage. This gets climate agreements. We do try to limit major drivers of greenhouse gas emissions. The question that asks for geoengineering comes naturally: how can we actively tackle climate change?

Reading this will introduce you to

Common geoengineering techniques

Some of the risks of geoengineering

Some of the risks of ignoring geoengineering aka. Why you should care

Where the research stands

How politics could engage in that topic

Reasons for the lack of media and political traction of geoengineering

There are two major techniques that are currently discussed as medicine for climate change, aka. geoengineering: Carbon dioxide removal and solar radiation management. Both seem canonical and both come with significant risks.

Carbon dioxide removal aims to remove emitted CO2 from the atmosphere

The first one is carbon dioxide removal (CDR). There is scientific consensus that CO2 piling up in our atmosphere is a major driver for our earth’s temperature to climb up the scale. Instead of just mitigating by pumping less out, CDR is the geoengineer’s answer to this problem by just removing the culprit out of our atmosphere. This can be done using various methods. These include: bio-energy with carbon capture and storage (BECCS), biochar, ocean fertilization, enhanced weathering, and direct air capture when combined with storage. These techniques mostly have a focus on capturing carbon and transforming it into a more usable format, or just storing it. Combining some of these techniques basically gives you carbon-negative energy sources. Noticeably, some of these approaches seem rather natural, like fertilizing oceans or planting and burning plants for biomass, and hence, (at least in a small-scale picture) safer to use. We’ll get more into details later. Either way: CDR can only do so much. An important discussion to have is whether we first need to drastically reduce CO2 emissions in order for CDR to make sense. But we’ll also get more into that later.

Solar radiation management for limiting the solar energy being absorbed by the earth

Instead of removing the CO2 that contributes to temperature increases by capturing energy on the earth, one could actively try to reduce the energy that comes to the earth from the sun. This is referred to as solar radiation management (SRM) or solar engineering. It can achieved by reflecting solar radiation, e.g. by putting large mirrors in space as this was actually proposed in 2001 to the US government. One of the most efficient options to achieve this turns out to be injecting light-reflective sulfur aerosols into the stratosphere. We even have some experience of natural injections arising from volcano eruptions: In 1991 Mount Pinatubo injected about 15 million tons which resulted in a 0.6°C decrease of avg. global temperature. Another way to manage solar radiation is to make clouds more “shiny and bright” (translates to reflective) by treating them with saltwater spray which results in the conglomerating of little water droplets to larger droplets.

It is interesting to note that SRM techniques tend to be much cheaper than CDR ones. Particularly sulfur aerosol injections could be cost effectively achieved at around €1b a year — a globally significant investment, that could be afforded by various individuals. But this cost does not factor in risk. Neither does it factor in the incompleteness of SRM with regards to CO2 emissions.

Engineering experiments and new technologies, what could go wrong?

Launching a (large-scale) technology often yields unforeseen effects. Usually these effects flow back into the technology and make it a better technology. Cars. Airplanes. Internet. AI. I guess you could call these effects and feedback loops a regular aftertaste of progress. For a technology with large-scale applications it is impossible to be thoroughly explored until the last detail, ever. Eventually the technology enters the market or not. Different countries handle this differently. For instance Germany, as a rather risk averse and change-resistant country, requires much more up-front qualifications that need to be proven before a new technology can be introduced (particularly in the GMO or pharma industry). This is good for reducing risks. But launching new technologies and taking risks is also necessary for progress. One of the more present discussions relates to the experimentation with autonomous driving on public roads. The value of risk seems high. But how high is the risk? Let’s take that question to geoengineering.

What are the risks? What is the worst-case scenario of a geoengineered world?

When talking about risk, we always talk about potential outcomes and their probability to occur. We know, that the probability of unforeseen significant side-effects happening in case of starting geoengineering attempts is very high. This is mostly due to the fact that we understand global climate very little. There is an enormous variety of factors all over and around the world contributing to the weather you see when you look out the window right now. This is also why weather prediction is never 100% accurate. But we see improvements of forecast qualities with progress in computational power, which is leveraged by intelligently including more factors into prediction calculations. Now consider a human technology with the potential to impact the climate in a significant way in less than a century. This would be an incredibly drastic and sudden change in our earth’s history, that for sure would have a long lasting hardly reversible impact (as we are already experiencing it). Basically this is to say, that there is a consensus among scientists, that it would be stupid to start applying large scale geoengineering right now.

Talking about the risks we need to say that we have very little practical experience — most of the research is based on lab experiments and relating it to real world implications is really hard. Here’s some risks that we think we know:

With SRM, to achieve pre-industrial temperature levels, we may need to inject ~1–15 teragrams of sulfur annually into the stratosphere. This amounts to more than the yearly water intake of the earth’s population. There is research indicating that injections at this large-scale will cause substantial increases in evaporation and decrease in precipitation (e.g. rainfall), particularly in South Asia or tropical Amazonian areas. In particular some areas that are highly dependent on the monsoon systems (affecting around 1b people), e.g. for food production, might be drastically impacted by losing existential resources and might experience natural catastrophes. We could also experience stratospheric ozone changes, potentially resulting in more cases of skin cancer or other diseases. But again, the story is more complicated: another side-effect of sulfur might be offsetting the impact, by diffusing some of the dangerous UV.

On CDR side, looking at Bio Energy and Capture Sequestration (BECCS), one would need to burn resources such as forests or dedicated crops at scale to produce bioenergy (and afterwards store it). To presumably have the necessary positive effect on the climate, we would need lands that amount for 7–25% of the net primary productivity of the world. These huge amounts might yield economic implications, such as increase of food prices, which in turn would worsen food supply for vulnerable people. On the other hand, using huge amounts of forest lands could also have drastic ecosystem implications as biodiversity would suffer. Furthermore, BECCS techniques also need large amounts of water resources. In fact, it might be as high as the current global irrigation need. However with more research, one could reduce risks and also increase practicability significantly (e.g. using less land). “There is research from UC Berkeley indicating a high practicability in leveraging algaes or direct air capture which implements filter systems within ambient air [basically artificial trees] and use carbon hydroxide to filter out carbon dioxide and store it permanently”, explains Burns and continues: “Both approaches could be applied using very little land and might have only a small footprint regarding water usage or biodiversity.”

SRM and the Umbrella Effect

In the big picture one noticeable scenario would be the following: what if we start doing SRM, a non-cause-focused GE technique, and start realizing that we get too dependent on it, but cannot sustain it? If, for only treating the symptoms, for technical or for political reasons, we did not manage actively reducing and stopping CO2 emissions, we could experience the so-called umbrella effect. This refers to a bulk CO2 being trapped in the atmosphere. The trapped CO2 could yield a dramatic temperature increase of 5–6° in just one or two decades, if SRM efforts were to be decreased — too much in too little time for our eco-system to adapt without catastrophic implications for humanity.

“It’s not: Party like it’s 1999 in terms of greenhouse gas emissions, or turn to GE. I think there’s a third way, to substantially increase efforts to decarbonize world’s economy.” — Wil Burns

CDR and the Paris Climate Agreement

Similarly, we could become world-champions in CDR and develop an emission-intensive culture, for being able to reduce CO2 anyway. A dependence of CDR would drive the intensity of its application, potentially to an unstable condition. This is why by many, this is seen as a long-term technology, in a post-emission-aware economy.

How does it compare to the worst-case scenario of business-as-usual?

We know different current and future scenarios that we attribute to climate change. We see them in the news every day. They do not look nice, but they might not even be the worst. Rising ocean levels yield threats on coast regions which requires adaptation. Tornadoes and earthquakes have shown destructive impact on central and north American regions. This year alone we have seen ten hurricanes with huge impact — over 60% more than in a typical year. Whole islands have been destroyed. Since wealthier nations might be responsible for climate change to a larger amount, it should be also their responsibility to support suffering nations. But unfortunately due to a lack of support, destruction and helplessness prevail in regions right now.

This illustrates that the comparability of scenarios is hard, or rather impossible: potential negative impacts from geoengineering efforts versus greenhouse gas emission efforts seem to have different impact areas. But we do know that the latter has sure implications. Large-scale and harmful implications. So in my opinion, this is enough reason to continue talking about GE.

Evidently, different segmentations of losers and winners will be created in each future. That’s why we need to talk about the morals and politics of geoengineering and how to move it forward to a winning scenario. But first let’s talk about the current research situation and about how to reduce risks for geoengineering applications that could have upsides to our future climate situation.

Reducing risks to (potentially) make the world a better place

Let’s start with the more “natural” bio energy approaches in CDR, that could have less risks. Remember the promising practicability of the algae or the air direct air capture approaches? What if I told you that there are currently almost no investments being made in that field of research (according to Burns). This needs to be changed if we want to survive the climate trends.

“If in 20–30y it will become clear that we can’t mitigate enough, and we get close to a critical threshold, we don’t want to be in the situation where we need to panic and try out a technique that has not been thoroughly assessed.” — Wil Burns

So, this exactly is the crux. Reducing risks can only work by heavily investing in research, first in lab experiments and eventually in small-scale environments. This is necessary due to our lack of climate understanding:

The sheer complexity of the nature of the climate is not only a red flag for starting to apply geoengineering technologies, but also a red flag for potential climate change scenarios, that we might also not understand far enough to be appropriately serious about it. I know that I repeat myself.

The current status of climate models

There are several climate models, all of them require high resources of computational power, as they all involve a lot of different interdependent variables. We discussed earlier how ridiculously complex the climate is (cf. butterfly effect) and it comes with no surprise, that current models just cover a small portion. In fact, they do not only cover a small portion, but also contradict each other quite quickly. To be pragmatic (or rather hacky) today, one can use the state-of-the-art models, by averaging them out or validating them against historic events.

This guy did not understand current climate models well enough.

An example illustrating current accuracies of our climate models: none of them captured the high pace of the disappearing of the arctic sea ice. “The behavior dynamics of melting ice sheets plus interaction with the ocean and the sun could take hundreds of researchers dozens of years, just to find that out”, Blackstock claimed in our discussion and argued: “We have the computational power, but cannot cover the complexity in all effects and feedback loops, such as melting ice having the effect that less solar energy gets reflected and hence absorbed by the earth.”

Can AI and strong computational power drive progress in geoengineering?

With the recent progress in computational power we can say that we might have enough to stem the computations for the climate models that we have. While this is true, Blackstock warns us, that what we not have is probably a combination of enough data and enough scientific understanding to reliably leverage the power. We would wish for a better understanding about climate models and much more data before we start applying AI for research. While governments start passing policies regarding potentially impactful AI technologies by using AI-generated proof points, the situation here, as Blackstock likes to emphasize: “comes with the major difference that we only have one earth.”

“The technology comes with the major difference that we only have one earth” — Jason J Blackstock

Eventually with more data, AI will become helpful in balancing the trend, that spending more on research typically drives technological progress faster, than the understanding of climate. But in any way, we will need to decide at some point how much understanding is enough to start applying climate engineering.

Political unfolding scenarios for a geoengineered future

Politically speaking, a country’s climate agenda, in particular its GE strategy, is of global relevance.

The usual procedure when tackling emerging international issues is that a number of countries, representing a large part of population (or rather GDP, think G20), starts investing in technology in an agreed upon way and consequently claims the decision authority regarding this issue. Typically this will be distorted towards their interest. Blackstock is confident that it will play out along these lines and that we can expect this board of 10–20 countries with the main purpose being, in addition to the Paris Climate Agreement, active climate engineering.

Solidarity needs to come first

We probably agree in saying that neither economical nor military dominance should be an enabler for a country to start large-scale experimentations. Globally, there need to be norms and some kind of shared ownership over the control, to make sure geoengineering efforts always align within a collective agenda. For this alignment, a canonical method would be setting up a no-fault insurance, as Blackstock suggested: collective payments into a fund, that will compensate for damages induced by geoengineering, without any discussion about who caused it.

As covered above, negative climate change effects would probably target other regions than negative geoengineering effects, whereas financial flows might again come from a disjoint region. Philosophically speaking, the measurability and therefore comparability of qualitatively different events (e.g. floods, illness, death, loss of ecosystem) targeting different quantities of different people is impossible. Shifting such events through GE or financially quantifying them, is something you don’t want to be deciding on. But it is an actual ethical dilemma, that we will need to face, similarly to how autonomous driving is forcing us to decide how a given fatal scenario should unfold eventually. Adding to that, financially weaker countries will always face inferiority in future scenarios: imagine a drought starting in South Africa — how will the impacted region be able to afford proving, that geoengineering applications (initiated by wealthier countries with powerful lawyers) caused this?

Political interpretation is set today

For a county, geoengineering competence and advance is a lever. The question becomes, if it will become understood as a tool of power along the likes of military or economic force. While one could argue, that military force also brings peace (at least in pre-Trump times), it remains individual power and we probably want geoengineering to become a more collective tool that works toward making the world a better place. Forming the rails to arrive at such goal would need to start today.

Lack of traction

If you read this far, I hope that you strongly wonder why geoengineering has not gotten more discussion and media coverage so far. My reason for hoping so is that I believe that the topic requires more traction in form of a mature discourse. So why has GE not gotten more traction?

Regarding media, it might be the fact that GE does neither indicate technological, social, nor political quick progress or urgency, relative to other emerging more graspable and self-manifesting technologies or media topics (think AI, IoT, etc.). Also for climate change getting into the public eye took a long time.

On the the politics side, it’s probably aversion of positioning towards large-scale engineering interventions with potential negative implications. This is even though lack of action comes with potential negative implications itself — just without the intentional decision. If media were to get more traction, this might urge politics to tag along. Also defining a clear ownership for climate engineering within a government would help to push it on the agenda.

To sum it up

In the language of the opening words of this article: if you know that there is a medicine with terrible side effects, but that might save your life along the way, you would want to increase the efforts in studying this medicine to de-risk its usage.

If you take something away from this article, please let it be the following: no geoengineering proponent would intend to apply large-scale GE as of today. We currently and in the foreseeable future know way too little about the climate. We wouldn’t know short-term effects, let alone long-term effects of GE. Exactly for this reason, there is a crucial need to open up the discussion and support research for climate engineering.