Climate change is here. Is it time to play God with our planet?
Let me be upfront with you: I don’t have a clean answer to that question. Neither does science. And
anyone who tells you they do – on either side – is either oversimplifying or hasn’t looked closely enough.
What I can do is walk you through what’s actually on the table, what the numbers look like, and why this
might be the most consequential scientific and ethical debate of our lifetimes.
Buckle up.
The problem is worse than you think
Here’s a number that should make you put down your coffee: we are currently on track for roughly
2.5–3°C of warming above pre-industrial levels by 2100, even with all current national commitments
honored. The Paris Agreement target of 1.5°C? We will almost certainly blow past it within a decade. The
carbon removal pledges made at COP28? They require technologies that don’t yet exist at scale. Global
emissions, after a brief Covid dip, hit a record high in 2023
‘m not saying this to be dramatic. I’m saying it because the context matters enormously for understanding why serious scientists – people who have spent careers studying these systems, who understand better than anyone how badly things could go wrong – are now cautiously, nervously, reluctantly discussing whether we need to start engineering the planet’s climate directly.
Desperate times. Desperately complex measures.
Option 1: Block the sun
The more radical-sounding proposal is called Solar Radiation Management, or SRM. The most discussed
variant involves injecting sulfur dioxide aerosols into the stratosphere – essentially mimicking what
happens after a large volcanic eruption.
When Mount Pinatubo erupted in 1991, it blasted roughly 20 million tonnes of SO₂ into the stratosphere. Global average temperatures dropped by about 0.5°C for roughly two years. SRM would replicate this effect deliberately and continuously, using high-altitude aircraft to maintain a reflective aerosol layer that bounces a small percentage of incoming sunlight back into space.
The physics are genuinely elegant. Reflect just 1–2% of incoming solar radiation and you offset several
degrees of CO₂-driven warming. The cost estimates, while uncertain, are surprisingly low compared to
almost any other climate intervention – somewhere in the range of $2–8 billion per year to deploy at
meaningful scale. That’s cheaper than a mid-sized infrastructure project. It could, in principle, be
deployed within years, not decades.
So why isn’t everyone celebrating? Because the downsides are terrifying in their complexity
The planet’s atmosphere is not a uniform system. Aerosols injected over the tropics don’t stay there. They spread globally – but they spread unevenly, and the effects on precipitation patterns, on monsoon cycles, on the jet stream, are enormously difficult to predict. Climate models suggest that aggressive SRM could reduce rainfall across the Sahel and parts of South and Southeast Asia – regions that are already desperately water-stressed and that had nothing to do with creating the carbon problem in the first place.
There’s also a phenomenon researchers call “termination shock.” Once you start SRM, you cannot stop
without warning. The CO₂ that caused the underlying warming is still there, in the atmosphere,
accumulating. The aerosols just mask it. If the program were halted suddenly, due to political collapse,
funding failure, conflict, anything, temperatures would rebound violently within years, far faster than
ecosystems or human societies could adapt to. You would have traded a slow crisis for a fast one.
And perhaps most troubling of all: who decides? Who decides how much cooling? Who decides where
the aerosols go? What happens when Country A’s SRM program shifts monsoon patterns and devastates
Country B’s harvest? There is no international framework for this. There is no court, no treaty, no agreed
principle. We would be entering completely ungoverned territory, wielding planetary-scale power with the governance apparatus of the 19th century.
Option 2: Pull CO₂ out of the sky
The other major category is Carbon Dioxide Removal, or CDR, and this is where the engineering gets
simultaneously more virtuous and more humbling.
Direct Air Capture (DAC) facilities use chemical reactions to literally grab CO₂ molecules out of ambient
air and compress them for permanent underground storage. The logic is impeccable: you’re removing the thing that’s causing warming, not just masking it. Unlike SRM, you’re treating the disease, not the symptoms.
The problem is cost and scale that borders on the staggering. Current DAC facilities capture CO₂ at
somewhere between $300 and $1,000 per tonne. We need to remove billions of tonnes per year to make a meaningful dent. At even $300/tonne, removing just one billion tonnes annually would cost $300 billion, every year, indefinitely. The entire US federal budget for scientific research is around $70 billion. The gap between current capacity (a few hundred thousand tonnes per year globally) and what’s needed (gigatonnes) is several orders of magnitude.
There’s also the energy problem. DAC is extraordinarily energy-intensive. If you power it with fossil
fuels, you partially defeat the purpose. If you power it with renewables, you’re competing with the rest of the energy transition for clean electricity. The math doesn’t become comfortable until you assume both massive cost reductions and a largely decarbonized grid, which is a lot of assumptions to stack before you claim victory.
Other CDR approaches – enhanced weathering (spreading silicate rock dust on agricultural land to
accelerate natural CO₂ absorption), ocean iron fertilization, bioenergy with carbon capture – each have
their own complex risk profiles, uncertain efficacy at scale, and potential for unintended ecological
consequences.
CDR is less scary than SRM. It doesn’t carry the same catastrophic termination shock risk. It doesn’t
geopolitically weaponize rainfall. But it’s slower, more expensive, and more energy-hungry, and we
simply don’t have the luxury of time that “slower” implies when we’re talking about crossing tipping
points in the cryosphere and deep ocean systems.
The debate nobody wants to have
Here’s where it gets genuinely philosophical, and where I think the most interesting STEM-adjacent
questions live.
There’s a serious argument, made by serious people, that researching and developing geoengineering
technologies is a moral obligation. The logic runs like this: the people who will suffer most from
unmitigated climate change are not the people who caused it. They are people in Bangladesh, in
sub-Saharan Africa, in small island nations. If we have tools that could reduce their suffering, even
imperfect and risky tools, declining to develop them on principle is a form of privilege – a choice that the
wealthy and the comfortable make on behalf of the vulnerable.
There’s an equally serious counter-argument. It runs: geoengineering is a moral hazard. If political leaders and fossil fuel interests believe that there’s a technological backstop – that someone will just fix the atmosphere when things get bad enough – the political will to make the actual painful emissions cuts
evaporates. Research on geoengineering signals that we don’t have to change our behavior, and that
signal, in a world where political will is the binding constraint on climate action, could cost us far more
than the technology could ever save.
Both of these arguments are compelling. Both are made in good faith. And they are almost impossible to resolve empirically, because the counterfactual – what happens to political will in a world with vs. without geoengineering research – is not something we can run a controlled experiment on.
What I know is this: the governance frameworks don’t exist. The international agreements don’t exist. The ethical principles for equitable deployment don’t exist. And the technologies, for now, are nowhere near the scale needed. We are having the deployment debate before we’ve done the foundational work.
What the science actually says
The IPCC’s Sixth Assessment Report – the most comprehensive synthesis of climate science ever
compiled – includes geoengineering in its mitigation pathways, but with severe caveats. The report is clear that SRM “would not address ocean acidification and that many uncertainties and risks exist.” It treats CDR as necessary in virtually all scenarios that limit warming to 1.5°C, but notes that at the required scale it “faces governance, economic, technological and social barriers.”
Translation: we probably need CDR. We might need some form of SRM. Neither is anywhere close to
ready, and our governance systems are nowhere close to equipped.
The honest scientific consensus is something like: these tools exist on a spectrum from “probably
necessary and manageable” (afforestation, soil carbon, enhanced weathering at modest scales) to “possibly necessary and deeply uncertain” (large-scale DAC) to “potentially necessary and genuinely
frightening” (stratospheric aerosol injection). And we should be researching all of them – carefully,
transparently, internationally – not because we want to use them, but because we need to know what we’re choosing between.
My take (and why you should form your own)
I believe we should fund robust, internationally coordinated geoengineering research. Not deployment – research. Controlled outdoor experiments with full transparency. The people who are most opposed to this research are, I think, underestimating how bad the baseline scenario is. The people most enthusiastic about it are, I think, underestimating how badly unilateral or premature deployment could go.
The framework I find most useful is this: geoengineering research is like studying the properties of a fire
extinguisher while your house is slowly filling with smoke. You’re not endorsing arson. You’re not giving
up on ventilation. You’re just trying to understand what tools exist, under what conditions they work, and what happens if you use them wrong – because the day you actually need them is the worst possible time to find out.
The climate crisis is real. The urgency is real. And the questions about how far we’re willing to go to
address it – what risks we’ll accept, whose risks, decided by whom, for whose benefit – are not just
scientific questions. They’re the most consequential political and ethical questions of this generation.
We don’t get to sit this one out.
Written by Fida Wafiq
