Geo-engineering and the Environment

Monday 23rd June 2025 Westminster Hall

14:50

[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.”

16:41

[Pippa Heylings (South Cambridgeshire) (LD)]

It is a pleasure to serve under your chairship, Ms Furniss.

It is important to set the debate and the e-petition in the context of the last couple of weeks. Last weekend saw another hottest day of the year on record, triggering an official heatwave and accompanied by an amber heat health warning, which means that because of high temperatures significant impacts are likely across health and social care services, including a rise in deaths, particularly among those aged 65 and over and people with health conditions. The Met Office puts the chance of us seeing another 40° weather event at 50:50, with a 45° day on the cards in the current climate. That is like an average summer day in Death Valley. I cannot imagine how the people and the natural environment in my constituency or the rest of the UK could cope with that.

As well as record-breaking temperatures, the weekend brought an increase in the threat of greater destabilisation in the middle east, with escalating conflict between Israel and the US and Iran. Unsurprisingly, on Sunday night oil prices soared to their highest since President Trump’s return to office, as the energy markets digested the news of the attacks on nuclear facilities in Iran. We do not yet know whether the situation in the middle east will lead to an oil supply shock. The Iranian Parliament has threatened to close the strait of Hormuz, which would choke the flow of oil from the region. Ordinary people will once again face volatile prices, hitting their pockets, as energy becomes more expensive and the cost of living is exacerbated.

Over just one weekend, we have seen our vulnerability to extreme weather conditions as a result of our failure to tackle climate change, and our vulnerability as a result of our dependence on global fossil fuels supply and prices. That underlines, once again, our need to strengthen our home-grown energy security and reduce our polluting emissions by accelerating investment in renewables and clean, green energy. Our emissions are not falling fast enough, and we are not on track to meet our legally binding climate targets. The world is set to surpass 1.5° of warming in the next decade. That is the context in which the petition was brought forward.

We need to address the root causes of climate breakdown, as my hon. Friend the Member for South Cotswolds (Dr Savage) said. The Climate Change Committee was clear last year that only a third of the emissions reductions required to achieve the country’s climate targets are currently covered by credible plans. Although it is true that our emissions are now less than half the levels they were in 1990, largely due to the phase-out of coal and the ramping up of renewables, we will now need ambitious action not just in the energy sector but across transport, buildings, industry and agriculture. The plans left by the previous Government did not deliver enough action, so we must do more. Nevertheless, even with aggressive investment in renewables and actions to decarbonise key sectors, we will still have to deal with residual emissions from heavy industries, particularly aviation, shipping and steel.

The balanced pathway, developed in the Climate Change Committee’s seventh carbon budget, tries to reduce emissions across all sectors of the economy as far as credibly possible, in line with cost effectiveness and feasibility constraints, minimising the use of engineered removals. However, even the committee recognises that we need to go beyond cutting emissions and to start work on the engineered removal of greenhouse gases from the atmosphere. That is why removals are part of the Government’s net zero strategy.

As we have heard, geo-engineering refers to deliberate, large-scale projects to reduce carbon and cool the Earth’s climate system to address climate change. In greenhouse gas removal terms, that also includes direct air carbon capture and storage and bioenergy with carbon capture and storage, some of which we are already using. We have seen sizeable investments from the Government into carbon capture storage. That could accommodate large-scale BECCS and DACCS, which clearly will be dependent on carbon capture and storage, but that is a measure of last resort for those hard-to-decarbonise sectors.

Living in South Cambridgeshire, I am close to the border with Cambridge. Since 2019, under climate expert Professor Sir David King, the University of Cambridge has been undertaking some important research into greenhouse gases at the Centre for Climate Repair. Among other things, it has been looking at something that brings climate and nature approaches together into balance again, such as marine biomass regeneration, which aims to restore whale populations, and ocean biomass to boost nutrient recycling and phytoplankton growth, because healthier oceans can naturally absorb more carbon dioxide and support global climate goals.

The centre has also been looking at the role of giant kelp, which grows rapidly and captures large amounts of carbon dioxide. When it sinks to the ocean floor, it stores carbon for the long term, offering a powerful, nature-based carbon removal method. Those are just two of the types of approaches that are being investigated. Quite rightly, the Government funded an independent review of greenhouse gas removal approaches, led by former MP Dr Alan Whitehead, covering nature-based solutions and engineered removals, such as direct air capture.

We saw in the Government’s response to the e-petition that they are currently working with the British Standards Institution to develop greenhouse gas removal methodologies, some of which may use sustainable biomass and require coming up with biomass sustainability criteria. There are some ways in which we could see greenhouse gas removal as a kind of guardrail for helping to decarbonise the atmosphere.

The e-petition also makes reference to solar radiation modification, which is an area that causes more concern. The Government have announced that they are not in favour of using SRM and have no plans for its full deployment. That position was made clear by the Minister in January, who said that the ongoing SRM research is for modelling only. The Government’s views on SRM are in accordance with those of the Liberal Democrats; we think it should not go to full deployment. We also think that the money invested in SRM research could have been better allocated to other measures for dealing with nature-based removal. I agree with Professor Mike Hulme that the cost of the research is an extraordinary amount of taxpayer money to invest in speculative technology. He is right to say, as I have already said, that the money could be better spent on reducing our dependence on fossil fuels or removing carbon dioxide from the atmosphere.

Geo-engineering is not a silver bullet. It must never be used as an excuse to delay decarbonisation through embracing and investing in renewables. We must remember that the first stop in our fight against climate change and securing energy security is investment in the transition to renewable and clean energy. Any amount of greenhouse gas removal will ultimately compromise the fight against climate change. As Dr Vaughan from the Tyndall Centre for Climate Change said:

“SRM methods do not address the causes of climate change”.

However, a blanket ban on geo-engineering, as the motion proposes, would be short-sighted and self-defeating as we explore the other methods that I have discussed. Let us therefore champion governance built on transparency for any kind of research and standards in geo-engineering and climate action, which is ambitious and grounded in our transition to home-grown clean, green energy.

16:50

[Nick Timothy (West Suffolk) (Con)]

I am pleased to respond to this brief debate on geo-engineering and the environment, Ms Furniss. I congratulate the hon. Member for South Cotswolds (Dr Savage) on starting the debate. I agree that solar radiation management would be a reckless experiment that risks all our futures.

The hon. Member for South Cambridgeshire (Pippa Heylings) used the opportunity to speak about climate change. Although she and I probably disagree profoundly about the wisdom of the net zero target and the plan to decarbonise the whole grid by 2030, I am sure she opposes, as I do, the giant solar and battery farms that the Government want to impose on both our constituencies and most of the east of England.

My party’s position on SRM is clear. We oppose any attempts to seed the sky, and every effort must be made to be respectful of nature and our planet. Chasing such hare-brained scientific schemes to interfere with the climate and the atmosphere will not give us answers to any live public policy dilemmas. The Met Office has confirmed that we do not have enough evidence to understand how effective geo-engineering like SRM might be, and we do not know what unintended consequences might occur for human and environmental health.

Ministers have said there are no plans to fund experimentation with solar radiation modification, but public concern was prompted by the Advanced Research and Innovation Agency offering £56.8 million of public money to examine climate cooling theory. It is important to say that the research does not, as far as I am aware, include any practical attempts to manipulate the climate, but was a study in relation to the theory of these methods.

Having been very clear about the Conservative position, I invite the Minister to provide a clear statement that the Government will not support SRM. Given the concern expressed by the public through the petition and the members of the public attending today, I am sure she will want to give everybody an unambiguous reassurance that that is indeed the case and that the Government will not come forward with such methods.

16:53

[The Parliamentary Under-Secretary of State for Energy Security and Net Zero (Kerry McCarthy)]

It is a pleasure, as always, to see you in the Chair, Ms Furniss. I congratulate the hon. Member for South Cotswolds (Dr Savage) on leading the debate and on showing respect for the notion behind the petition, because that is not always the case when people come and present views. I hope the petitioners feel that she has done justice to their stance.

I will set out what we are doing to tackle the issues highlighted in the petition. A lot of the concerns that have been raised today and over the last few weeks have been driven by recent research proposals to explore climate cooling technologies, as well as the media coverage that that has caused, and I will come on to those concerns in a moment.

Geo-engineering is a term commonly used to refer to two groups of technologies, as has been mentioned: greenhouse gas removals and solar radiation modification. Those are two very separate, very different approaches to addressing climate change, and the UK has two very separate, very different positions on their use. Greenhouse gas removals actively remove greenhouse gases—predominantly carbon dioxide—from the atmosphere for highly durable storage, resulting in negative emissions. They are vital to achieving net zero, and we support their deployment. Solar radiation modification, on the other hand, describes a set of interventions that aim to cool the earth, largely by reflecting some of the sun’s energy back into space.

[Douglas McAllister (West Dunbartonshire) (Lab)]

I receive regular communication from constituents asking me for my opinion on the UK’s involvement in chemtrails and geo-engineering. Will the Minister reassure us that chemtrails are actually condensation trails and nothing to do with solar radiation management, and that the UK Government have not deployed SRM techniques and have no plans to do so?

[Kerry McCarthy]

I can certainly reassure my hon. Friend. I have received quite a lot of correspondence on that, which MPs have passed on from their constituents. I have answered written questions—which are in the public domain—and replied to queries on both those points. I will try to express as clearly and vehemently as I can that we have no plans for SRM.

On the supposed chemtrails issue, that is a term used by some people who claim that the white trails seen behind high-altitude aircraft on clear days contain undisclosed chemical agents intended for a covert atmospheric spraying programme. They are, in fact, as my hon. Friend said, contrails, which form when warm, moist aircraft exhaust fumes mix with cold air at altitude. Under certain atmospheric conditions, contrails can persist and spread out to form cirrus-like clouds before disappearing. There is no deliberate spraying of chemicals in the skies over the UK for climate modification. We are not in favour of SRM and have no plans to change that position; I will say more on that in a moment, but first I want to add a little more on greenhouse gas removals.

Making Britain a clean energy superpower is one of the five missions of this Government, delivering clean power by 2030 and accelerating progress towards net zero across the economy by 2050. I note the comments from the hon. Member for South Cambridgeshire (Pippa Heylings) about the UK being off track to do that. We will be publishing our carbon budget delivery plan by October; as she said, the previous Government were taken to court for failing to produce adequate policies to match the ambition. Obviously, there is no point in setting targets unless they can be delivered. We will set out our plan in due course, and then talk about the seventh carbon budget and meeting our nationally determined contributions.

We must do everything we can to reduce greenhouse gas emissions—that is our starting point. We need that effort to be shared across all Government Departments, and we need everyone to play a role.

[Mr Angus MacDonald (Inverness, Skye and West Ross-shire) (LD)]

I hope this is not too much of a diversion, but the Minister will know that mains gas is 6p per kWh, largely imported and certainly a carbon fuel, while renewable energy is selling at 24p per kWh. We cannot get the public behind us as long as the environmental tariffs are on the renewable energy and not on the carbon fuel. May I have her opinion on that?

[Kerry McCarthy]

I will not be tempted too far down that path, other than to say that it is very much on our radar. We know that renewables are the cheaper option, but that needs to be reflected in the prices that people are charged. Today, we announced measures in our industrial strategy to bring down energy prices for industry as part of industrial decarbonisation, but on the consumer side it is a work in progress, and the hon. Gentleman can expect to hear more soon.

The starting point is reducing emissions. We know that emissions are hard to abate in some sectors, and that we will not be able to do it fully. Greenhouse gas removal technologies will therefore be important to balance those residual emissions. That is recognised internationally by the Intergovernmental Panel on Climate Change and by our independent Climate Change Committee, whose latest advice to Government for setting the seventh carbon budget modelled around 36 megatonnes a year of engineered removals by 2050 to help us reach net zero.

Greenhouse gas removal approaches fall broadly into two categories: nature-based approaches, such as afforestation; and engineering-based approaches, such as direct air carbon capture and storage, bioenergy with carbon capture and storage, biochar, and enhanced rock weathering.

I know that both the hon. Members for South Cotswolds and for South Cambridgeshire are passionate about nature-based approaches, which can play an important role in removing and storing carbon dioxide at scale, while delivering a range of additional environmental improvements, such as improvements in biodiversity, air quality and soil health. Those co-benefits are important, too.

We are acting on nature-based approaches. In March, we announced the creation of the Western forest, the first new national forest in over 30 years. It will see 20 million trees planted across the west of England in the coming years, which I very much welcome as a Bristol MP. We also plan to expand nature-rich habitats, such as wetlands and peat bogs, including restoring hundreds of thousands of hectares of peatland—we also seek to promote such work internationally.

We are in the middle of London Climate Action Week, and many visitors from Brazil are talking about what they seek to do for their tropical forests’ “forever facility” at COP30. I was excited to hear what the hon. Member for South Cambridgeshire said about whales and giant kelp, as I have been talking to my officials about the role they play—it is good to have scientific back-up for my views. During London Climate Action Week, we are focusing on the important role of the voluntary carbon and nature markets in securing investment for blue carbon and our forests.

However, we know that nature-based approaches need to be complemented by engineered solutions to remove carbon dioxide at the speed and scale necessary for us to meet our targets. Many countries agree with us on the important role that GGRs will play, and large-scale removal projects are currently operating or being planned around the world. We are also committed to supporting the deployment of engineered GGRs.

Access to carbon capture, usage and storage infrastructure is vital for many GGR technologies, and the Government are supporting the development of the CCUS network by allocating £9.4 billion in capital budgets over the spending review period. The network needs regulation, and we have an established environmental regulatory regime, with several regulators evaluating the environmental impact of GGR and CCUS projects.

Any GGR project deployed in the UK must comply with the relevant regulations and planning processes to ensure it is managed responsibly and that any environmental impacts are addressed, including impacts on biodiversity, pollution and local communities. We will continue to work with the necessary Departments, regulators and other public bodies to ensure that the UK’s regulatory environment is well placed to support the deployment of GGRs without causing environmental harm.

We take the integrity of removals very seriously. A robust GGR standard, including monitoring, reporting and verification, will be crucial in instilling public and investor confidence that removals through engineered GGR projects are genuine and verifiable. In other words, when someone says they have removed 1 tonne of CO₂, at least 1 net tonne of CO₂ must have been removed from the atmosphere once emissions relating to the entire process are taken into account, and we have commissioned the British Standards Institution to develop those assessment methodologies.

Although the petition refers to geo-engineering in a broader sense, solar radiation modification is possibly why it has attracted so many signatures. As I have said, SRM is a set of technologies that could cool the Earth, largely by reflecting some of the sun’s energy back into space. However, the consequences of SRM are currently poorly understood, with significant uncertainty about the possible risks and impacts of deployment.

I make it clear for the record that the Government are not deploying solar radiation modification and have no plans to do so. There will be no spraying of chemicals in the skies over the UK for SRM, geo-engineering or climate remediation. Our priority is to reduce greenhouse gas emissions from human activities and to adapt to the unavoidable impacts of climate change.

However, we do need to understand the potential risks and impacts of SRM. We have a very clear commitment not to deploy it, but we need to understand what would happen if other people chose to. That includes engaging with the Met Office Hadley Centre climate programme, the Natural Environment Research Council and the Advanced Research and Invention Agency, the coverage of whose climate cooling research programme has triggered some of the concerns we are talking about today.

ARIA is an independent research body that was set up by the Department for Science, Innovation and Technology. Although it is sponsored by that Government Department, it has complete autonomy on its project choices, which goes to the point about whether that is the best use of public money, as ARIA is responsible for its own choices. It is conducting cautious, controlled research aimed at improving the understanding of SRM risks and impacts, but it is not deploying SRM technologies. I say again that its research will not release any toxic materials, nor will it alleviate the urgent need for increased decarbonisation efforts. There is no substitute for decarbonisation, which is why we are pressing on with our missions for clean power and net zero.

The science is clear that, without rapid action, we risk irreversible damage to the planet’s biosphere. To halt global warming, the world needs to reach net zero greenhouse gas emissions, which includes the UK’s emissions. I hope I have reassured the hon. Members present, and the constituents they represent, that the Government are not deploying SRM technologies and have no plans to do so, and that the environmental impacts of greenhouse gas removal technologies—the other wing of geo-engineering—will continue to be monitored as those technologies scale up in the UK.

17:06

[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.

17:09

Sitting adjourned.