What happens if a country unilaterally decides to implement a large-scale experiment to cool a part of the planet? And what if this potentially generates unintended consequences beyond its borders?
Sir David King, 86, is an eminent British chemist and climate expert. And the South African-born scientist isn’t so concerned about researching the extreme measures that, he believes, could be the solutions to global warming. Rather, he’s worried about their implementation before countries agree on how they should be used.
Ten years ago, as the UK’s climate negotiator, King was one of the driving forces behind the inclusion of the 1.5-degree Celsius target in the Paris Agreement… a safety limit that’s now beginning to be exceeded. He’s currently president of the Climate Crisis Advisory Group. A few days ago, he participated in a conference on climate change in Madrid, organized by the University of Vigo and Comillas Pontifical University, in conjunction with the Spanish National Research Council (CSIC).
Question. Why do you argue that we need a new approach to combating global warming?
Answer. There are many reasons, but I’ll give you three. Firstly, in the last 10 years, Greenland has been losing 30 million tons of ice every hour. If all of Greenland melts, sea levels will be [24 feet] higher across the planet, [because] there’s a lot of ice there. Now, is this irreversible? Maybe yes, maybe no. It’s not clear to us why it would stop melting. In any case, the future of humanity doesn’t look very good if sea levels rise by [24 feet]… and this is just [because of the situation in] Greenland. If we look at the West Antarctic Ice Sheet, that alone could contribute another [20-foot] sea level rise. If you add all of this up, [the rising oceans] will change the map of the world.
The second factor is that temperatures have already risen well above 1.5 degrees Celsius. In January of this year, the global temperature was 1.75 degrees above pre-industrial levels. It may decrease, so we can’t focus on a single figure… but the 1.5-degree target is already being exceeded.
Thirdly, I only have to mention [the 2025 European and Mediterranean wildfires] for you to see the enormous risk that we’re already facing.
Q. What needs to be done to rebalance the planet’s climate?
A. Let’s suppose we could achieve net-zero emissions tomorrow. Of course, that’s impossible… but if we could, would the ice stop melting in Greenland? No. Greenland is already melting irreversibly.
We need more action now. And there are four essential Rs for the future of humanity: reduce, remove, repair and resilience.
The first thing we must do — and let me stress this — is reduce emissions, quickly and decisively. Today, we’re emitting more than 40 billion tons of CO₂ into the atmosphere every year. And [this amount] keeps increasing. If we don’t reduce emissions, frankly, we’re cooked. But we also need to remove greenhouse gases that are already in the atmosphere; we must devise new ways to capture and remove gases like CO₂ and methane.
The third R is “repair.” Can we stop the ice from melting, [the ice that’s] formed over the Arctic Sea in the winter? There are several research groups around the world studying this. And the fourth R is for “resilience.” Every city in the world needs to develop resilience. Every region of the world needs to adapt to what’s going to happen. Every mayor should be concerned about this.
Q. Why would it be beneficial to prevent the ice on the Arctic Ocean from melting in summer?
A. In the winter, ice forms over the Arctic Ocean, but in the summer, within three days, that thin layer of ice is gone; the blue sea soaks up the sun.
Q. But some of these actions intended to “fix” the planet’s climate are extreme measures that have never been tried before…
A. The word “extreme” already carries a negative connotation. But yes, to stop climate change, we need extreme measures. It’s true that they haven’t been tried — and this also worries me — but we need a governance framework to manage all of these technologies.
Take India, for example: hundreds of thousands of Indians can die in a single summer from heat stress. The current number is already high, but [official] figures aren’t published. Deaths could exceed one million [per year] due to the [heatwave]. Is the Indian government going to prevent its scientists from trying to solve this problem?
What worries me is that a country or a private company might do it alone. There are scientists studying how to cool the planet; no one should stop these experiments. But this research shouldn’t be put into action until we have adequate global governance procedures.
Q. What do these techniques to cool the planet look like?
A. The technique I’m most familiar with is marine cloud brightening. A dark cloud — like those that bring rain or snow — absorbs the sun’s heat. However, a white cloud reflects sunlight back into space. The idea is to cover the Arctic Circle region with white clouds for three months of the year, using seawater. Tiny droplets of seawater can be created, which then rise with the heat and lose their water, leaving salt crystals suspended at about [6,500] feet, thus turning the clouds white. This is what we’re trying to do.
If something goes wrong and the clouds drift to places where people don’t want them, we can stop producing them. But the idea isn’t cheap. It would require 2,000 ships across the entire North Pole region… and this would cost many billions of dollars.
Q. Don’t you think it’s dangerous to apply climate engineering without knowing all its effects?
A. What’s happening now is very dangerous. Look at Hurricane Melissa: when it hit Jamaica, it was traveling at [120 miles] per hour. Where did we ever see such a fierce hurricane?
Q. And these extreme measures — whose effectiveness is also uncertain — aren’t they a distraction from reducing fossil fuel consumption?
A. The priority must be to stop using fossil fuels. Today, investment in renewable energy systems worldwide is in the order of hundreds of billions of dollars. The money I’m talking about [when it comes to these mitigating techniques] is in the hundreds of millions… a small price to pay to create a potentially manageable future for humanity. And I say “potentially” because you’re right, we don’t know if it will work. But we’re trying.
Q. Do you really think it’s possible for countries to reach an agreement regarding how to manage techniques that artificially alter the climate?
A. It’s very important that they do. But at this point in time, we can’t expect every country in the world to agree. I would say the same about all climate action. Neither Russia nor the United States is going to take serious action on climate change, but the rest of the world has to act on the four Rs. If we manage to reach an agreement between China, India, Brazil (which is hosting the COP30), the European Union and the United Kingdom, then we can hope that the U.S. and Russia will join later.
I refuse to believe that the U.S. and Russia’s refusal is the end of the game; it can’t be. I have young grandchildren. And the priority must be to stop using fossil fuels. Otherwise, we’re finished.
Q. Bill Gates has said that climate change isn’t going to wipe out humanity. He has called for a different approach that doesn’t focus so much on reducing emissions. What do you think?
A. You’re quoting someone who isn’t a scientist. I’m a scientist.
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