Geo-engineering and the Environment

Roz Savage Excerpts

Monday 23rd June 2025 Westminster Hall

[Dr Roz Savage (South Cotswolds) (LD)]

I beg to move,

That this House has considered e-petition 701963 relating to geo-engineering and the environment.

The petition was started by Antoinette Taylor and opened on 23 December 2024. As of 12 June 2025, it had gathered more than 159,000 signatures. Just two of those signatures were from my South Cotswolds constituency, so I clearly did not step up to lead this debate in an effort to win votes. I am here because I believe this issue matters deeply for our future and for the future of the planet on which we rely for life.

Geo-engineering is a broad term used to describe a range of large-scale interventions in Earth’s climate system, so I will start by clarifying a couple of definitions. Geo-engineering falls into two main categories: carbon dioxide removal and solar radiation management. The petition calls for a pre-emptive ban on both. CDR is about drawing carbon out of the atmosphere and can involve technology such as carbon capture, or nature-based solutions such as restoring forests, peatlands and grasslands. I have absolutely no problem with the latter. Trees do not need subsidies, peatlands do not break, and healthy soils not only store carbon but improve water quality, mitigate flooding and support biodiversity. They are our natural allies in the fight against climate change.

SRM is a different matter. It aims to reflect sunlight back into space by various means, such as using aerosols sprayed into the stratosphere, whitening clouds or even placing mirrors in orbit. SRM does not remove carbon. It does not stop ocean acidification. It does not reduce fossil fuel use. It masks the symptoms while the root cause, our fossil fuel carbon emissions, goes unchecked. Whatever options we consider as we confront the climate crisis, we must not be distracted from our overriding mission to tackle the key cause of climate change: our reliance on fossil fuels.

Let us talk about the risks of SRM. First, there is the issue of unintended consequences. Humanity does not have a good track record on this. Our weather systems are immensely complex, interconnected and not well understood. Altering sunlight could potentially disrupt monsoons or shift jet streams, or trigger droughts in some regions while causing floods in others. According to a report by the House of Commons Science and Technology Committee, SRM could delay ozone recovery by decades. It could disrupt rainfall patterns, and would do nothing to stop our oceans absorbing carbon dioxide and forming the carbonic acid that is affecting the viability of phytoplankton, which are essential for life on Earth, generating half the oxygen we breathe.

There is also the problem of scientific control. We cannot conduct a controlled experiment with SRM. We do not have two planets, one on which we conduct SRM and one on which we do not. There is no planet B to test it on. Once SRM is deployed, we are in effect launching a planetary experiment, with no ability to reverse it if things go wrong. As the petitioners have highlighted, even if SRM “works” in the short term, there is a risk that our climate will become dependent on continual injections. If the injections stopped for any reason, which in our turbulent geopolitical world is entirely possible, we would risk a phenomenon known as termination shock: a sudden extreme spike in global temperatures, which would be potentially catastrophic for life on Earth.

As for the chemicals used in SRM, the aerosols under consideration include sulphates and even aluminium. The matter is still being researched, and there is no definitive link between aluminium and conditions such as Alzheimer’s, but many scientists remain cautious about prolonged exposure. Sulphates are precisely the chemicals that we worked so hard to eliminate under the Montreal protocol, because of their role in depleting the ozone layer. We should consider carefully the possibility that deploying SRM could put us in direct violation of the protocol, which is one of the most successful international environmental agreements ever forged.

We must consider the human cost of climate change and any measures that we might take to mitigate it. Who decides the thermostat setting? Who gets more rain, and who goes without? Can we even control these things? The risks of failing to invest in technology to tackle the root causes of climate change threaten serious regional disruption. As always, it will almost certainly be the poorest and least responsible for the crisis who bear the brunt of the fallout.

Some will argue that we are still doing too little, too late to mitigate climate change, and I agree with them, but that does not mean that SRM is the right answer. SRM could take us out of the frying pan and into the fire. Instead of reaching for techno fixes, we need to do what we already know works: cut fossil fuel use, restore nature and—gosh—maybe even look at changing our behaviour, because at some point, sooner or later, behaviour change must be part of the picture. If we are honest, none of the technologies yet available to us—not even the most advanced forms of carbon removal—can keep pace with our current levels of consumption.

Globally, we are still emitting about 40 billion tonnes of carbon dioxide every year. If we continue on our current path—as an environmental campaigner for more than two decades, I very much hope we do not—we are headed for about 2.7° of warming by the end of the century. We know that the consequences of that level of warming include rising seas, more intense storms, loss of crop yields, the mass displacement of humans, accelerating biodiversity loss and heatwaves that will put many, many lives at risk.

Although carbon capture is often talked about as a solution, the reality is sobering. It is, for sure, less perilous than SRM, but the vast majority of carbon capture projects are still very small in scale, and many use almost as much energy to capture carbon dioxide as was emitted in the first place. To scale carbon capture up to a level at which we could even begin to think about continuing business as usual would require enormous amounts of infrastructure, energy and funding.

Meanwhile, it is increasingly clear that we have to transition away from fossil fuels. I am talking not ideologically but economically. The energy return on fossil fuels is falling. In the early days of oil, when we could just stick a nodding donkey in the ground anywhere in Texas and hit oil, we got about 100 barrels out for every barrel-worth of energy invested; today, the figure is down to close to 20 and still falling. At some point, the economics will simply stop making sense. Fossil fuels are finite, and the cost of extraction is rising, so given that we know we will have to make the transition at some point, sooner or later, why not do it sooner? The question is not whether we will move on, but whether we will do it on our own terms or wait until crisis forces our hand.

Some argue that we live on a planet on which the climate has always changed, but historically it has changed slowly, giving species time to adapt. The most dramatic climatic shifts took place before humans came on the scene. Our western civilisation has evolved during an unusually stable climatic period—the Holocene. Our infrastructure, food systems and settlements were all built around that stability. Shake the foundations and the whole structure becomes precarious. The rate of change we are now seeing is unprecedented in human history. Ironically, that puts us, in many ways the most adaptable of species, among the most vulnerable species on the planet.

I want to end on a positive note. This is not a story of despair. Yes, the situation is urgent, but it is not hopeless. If we act boldly and act now, we can still turn it around. Let us redirect investment away from planetary-scale experiments of dubious feasibility. I am not saying we are currently investing in such work; I am saying we should shift our focus away from technologies that may or may not deliver benefits and may or may not deliver catastrophic side effects. Let us instead focus on realistic, viable solutions that we already know work. Let us prioritise emissions cuts, the restoration of nature and behavioural shifts. Let us resist the easy temptation of silver bullets and choose instead the hard but honest work of transition. What is at stake is not just the climate, but our shared future. It is about not just statistics but the stories of people, places and ecosystems that deserve to survive and thrive.

I will finish by quoting the American farmer, poet and activist Wendell Berry, who said that the

“care of the earth is our most ancient and most worthy and, after all, our most pleasing responsibility. To cherish what remains of it, and to foster its renewal, is our only legitimate hope.”

--- Later in debate ---

[Dr Savage]

I thank hon. Members for their contributions to the debate. I also thank my hon. Friend the Member for South Cambridgeshire (Pippa Heylings) for highlighting possible solutions, particularly the ocean-based solutions that are very dear to my heart.

This debate seems to be one of those rare occasions where we find multi-party consensus. I am tremendously reassured to hear that the Government have no plans to deploy SRM in this country. It was interesting to hear a bit more about the work of ARIA, and I trust that its work will not open a door. Humanity has form, and once we know that something is possible, we are not always very good at holding ourselves back from deploying it. I trust that there will always be the utmost transparency, and I am very reassured to hear about the Government’s work with the British Standards Institution to ensure full transparency and accountability in the work done in that domain.

I will wrap up with a personal reflection. During my years of rowing solo across oceans to raise awareness of our climate and nature issues, I learned the hard way that we cannot fight mother nature. We cannot flout her laws and expect to win. Ultimately, she always has the final word, and the wiser path is to work with her. I hope that we will continue to emphasise nature-based solutions, as we can never go wrong with those. I fully appreciate that this is a climate emergency and that urgent action is needed, but let us not forget that mother nature can also be our greatest ally. We urgently need to act, not with hubris, but with humility, courage and care for the wellbeing of future generations.

Question put and agreed to.

Resolved,

That this House has considered e-petition 701963 relating to geo-engineering and the environment.