War Chests & Green Bets
Prashant, Hetti and Adam in conversation on stage at Octopus
June 2025
Featuring: Adam Bell and Hetti Barkworth-Nanton; moderated by Prashant Rao.
On 3rd June, Earth Set hosted one of its most provocative and clear-eyed discussions to date — a deep dive into the uneasy, increasingly urgent relationship between rising defence spending and climate ambition.
By sheer serendipity (or sharp timing masquerading as luck), the panel took place just one day after the UK government published its Strategic Defence Review — a document that confirmed what many already sensed: defence is once again a top-tier political priority. With expanded budgets, escalating threats and the language of "resilience" and "strategic autonomy" now embedded across government and investment discourse, we asked: what does this mean for net zero?
Can climate and defence goals align? Are dual-use technologies real opportunities or convenient narratives? And where will capital — and attention — flow next?
Decarbonisation as Defence
From the outset, the panel made it clear: we can’t disentangle climate from national security. A warming, unstable planet fuels conflict. A fossil-dependent economy is vulnerable to energy shocks and geopolitical pressure. Decarbonisation isn’t just an environmental necessity — it’s a defence imperative.
As Adam Bell put it: "Preparing for war means preparing to decarbonise. A resilient energy system — one that isn’t hostage to global fossil markets — is a safer system."
The panel noted that the Strategic Defence Review hinted at this logic, but lacked meaningful integration of climate foresight into core defence planning. If energy security, critical minerals, and global climate volatility aren't treated as structural threats, the UK's long-term resilience will remain underpowered.
Dual-use innovation: promise and problems
Hetti laid out where defence and climate tech are already converging: battery systems, hydrogen, micro-energy generation, distributed infrastructure. These are natural crossover points where military needs and net zero imperatives align.
But she also issued a reality check: “We’re still flying chinooks built 50 years ago.” Despite the talk of innovation, defence procurement tends to favour the known and tested — which makes genuine breakthroughs difficult to fund or scale.
This is why she argues for a change in how defence problems are framed. Rather than rigid specifications, the armed forces should increasingly articulate the problem to be solved, and leave space for innovators to respond. “Tell us what you need the outcome to be — not how to do it,” was her underlying message.
The procurement paradox
One of the evening’s most pointed insights was about much of the UK investment ecosystem, including VCs sees defence as bureaucratically inaccessible and financially unworkable. Despite hype around “defence tech” and NATO-aligned funds, Hetti was blunt: “The UK defence market is too small, international markets are hard to break into, and procurement is still a nightmare.”
However, dual-use businesses — those with commercial applications first, and defence potential later — may finally break the deadlock, but unless procurement radically improves, that bridge remains conceptual.
Infrastructure, vulnerability and battlefield learning
From distributed energy systems to armoured cables, the future of defence is local and resilient. The UK’s reliance on fossil fuels makes it strategically exposed; moving toward distributed renewables doesn’t just cut emissions — it makes sabotage and cyberattack harder.
Prashant raised Ukraine as a "crisis simulator": a place where decentralised energy, solar panels, and entrepreneurial battlefield innovation are not policy experiments but survival tactics. There was a clear message: waiting for war to innovate is not a strategy.
The Machinery of Government
The panel didn’t hold back in critiquing the UK’s institutional setup. Adam, reflecting on his time in BEIS, spoke of the civil service’s dual personality: surprisingly agile in moments of national emergency (like Covid), but structurally siloed and cautious the rest of the time.
Interdepartmental strategy — especially between MoD, DESNZ and HMT — remains weak. Climate and defence policy continue to operate on parallel tracks, despite clearly overlapping interests.
There was consensus that unless coordination improves, the UK will continue to miss industrial and investment opportunities that are staring it in the face.
Tone and Takeaways
What stood out — beyond the policy insight — was the tone. Earth Set evenings are often optimistic: forward-looking, ambitious, even gently utopian. This wasn’t.
This was a hard listen. The discussion wasn’t defeatist, but it was sobering. The trade-offs are real, the risks are here, yet neither the defence establishment nor the climate movement it appears, is fully prepared for the complexity of what’s coming.
Closing Provocations
Each panellist was asked what one structural change would unlock progress:
Adam Bell: Integrate energy foresight and climate vulnerability directly into UK defence strategy and planning.
Hetti Barkworth-Nanton: Build shared investment vehicles that bring defence and sustainability capital together — and design procurement processes that don’t kill ambition.
Prashant Rao: Use defence spending to shape markets, not just deliver capability — and measure its success in long-term resilience as well as readiness.
Thank you to Hetti, Adam, and Prashant for bringing rigour, experience and uncommon candour — and to all who joined us for this essential discussion.
