We passed the 1.5C climate threshold. We must now explore extreme options

 

We passed the 1.5C climate threshold. We must now explore extreme options

David King

We do not have the luxury of rejecting solutions before we have thoroughly investigated their risks, trade-offs and feasibility

 

Mon 7 Apr 2025 10.00 BST

https://www.theguardian.com/commentisfree/2025/apr/07/climate-solutions-extreme-options

 

As a lifelong scientist, I have always believed that if something is possible, we can find a way to achieve it. And yet, one of the starkest realities we now face is that the world is failing to meet its climate goals. Last year marked a historic and deeply troubling threshold: for the first time, global temperatures exceeded 1.5C above pre-industrial levels. Without drastic and immediate climate action, this breach will not be temporary. The consequences – rising sea levels, extreme weather and devastating loss of biodiversity – are no longer projections for the distant future. They are happening now, affecting millions of lives, and likely to cause trillions in damages in decades to come.

 

But we must think beyond our immediate horizons. When I read The Iliad, I am reminded that it was written 2,800 years ago. I often wonder: in another 2,800 years, what will people – if humanity as we know it still exists – read about our time? Will they see us as the generation that failed to act or one that made the choices necessary to safeguard the planet for the future?

 

We must act with this longterm perspective in mind. Scientists agree we need to bring greenhouse gas levels down to below 350 parts per million by the end of this century to ensure a liveable planet for future generations. Achieving this will require a four-pronged approach: reduce, remove, repair and resilience.

 

Reduction – cutting emissions rapidly and deeply – of course remains a critical priority. But we must also pursue the removal of excess carbon, explore repair techniques to stabilise key ecosystems and build resilience against the escalating impacts we are already experiencing.

 

One of the greatest challenges of climate science today is that many of the necessary levers to regain control are uncomfortable, even controversial. Ideas such as thickening sea ice to prevent collapse or brightening marine clouds to reflect sunlight may once have seemed extreme. Yet, as we contend with an escalating crisis, we must at least explore these possibilities. We do not have the luxury of rejecting solutions outright before we have thoroughly investigated their risks, trade-offs and feasibility.

 

As scientists, we must never advocate for deploying unproven interventions. Any repair or removal techniques must undergo rigorous research and assessment before we evaluate full-scale suitability. However, we must also be clear: these investigations must happen with urgency. The longer we delay, the fewer options remain on the table and the more likely that deployment will happen without the proper due diligence at a point of desperation.

 

Privately, many scientists acknowledge the need to advance research into these solutions, but there is a widespread reluctance to say so publicly. I understand this trepidation – some fear backlash, while others worry about giving ammunition to those who would use climate repair as an excuse to delay emissions reductions. There are also many who object on ethical, political or environmental grounds, often for entirely understandable reasons. We must respect these concerns and ensure that any research is conducted transparently, with input from affected communities and with the free, prior and informed consent of Indigenous rights-holders.

 

Yet, my question remains: if not now, then when? The climate crisis is worsening before our eyes. We cannot afford to remain silent on the necessity of responsible research into nature-based climate repair. We must explore these approaches as part of a holistic climate response, not in place of deep emissions reductions, but as a complement to them.

 

I commend the advocacy groups, scientists and policy leaders who have already broken their silence. Groups such as Operaatio Arktis, Ocean Visions and the Alliance for Just Deliberation on Solar Geoengineering are fostering open and inclusive dialogue about what responsible research should look like. It is time for more of us to speak up.

 

Throughout history, scientific breakthroughs have changed the course of humanity when leaders and communities worked together to act on the evidence before them. The Montreal protocol successfully phased out CFCs after the discovery of the ozone hole. Decades of renewable energy research have made solar and wind the cheapest power sources globally. We have faced existential challenges before and found solutions – because people were willing to pursue bold, responsible action.

 

Today, we face an even greater challenge. We must advance research into climate repair urgently, transparently and with the utmost scientific and ethical rigour. To do so, we must use our voices, collectively and courageously, before the choices are no longer ours to make.

 

Professor Sir David King is the head of the Climate Crisis Advisory Group. For more than 60 years, he has been a scientist and vocal advocate for acting on climate change. He has served as the UK government’s chief scientific adviser, the foreign secretary’s special representative for climate change and the head of the University of Cambridge’s chemistry department.