Frequently Asked Questions: Marine Cloud Brightening (MCB)
1. Could Marine Cloud Brightening (MCB) cause unintended climate consequences?
Marine Cloud Brightening (MCB), like any intervention, must be weighed against the escalating costs and human consequences of climate inaction. Currently, doing nothing is leading to millions of premature deaths each year—over 8 million from air pollution, 500,000 from extreme heat, and 65,000 from extreme weather events. The devastation from worsening hurricanes and extreme conditions will only grow, threatening lives, ecosystems, and economies.
The greatest risk is continuing on the current path, where unchecked climate change drives more destructive storms and weather, leading to even higher casualties and loss. MCB is designed to cool specific ocean regions by increasing cloud reflectivity, which in turn can help dampen hurricane intensity and save lives. If unintended consequences occur, the process is rapidly reversible—MCB operations can be paused or stopped within hours if models spot any problem. This flexibility makes MCB much less risky than allowing today’s disasters to worsen unchecked.
MCB works by enhancing processes already present in nature, specifically increasing cloud condensation nuclei with sea salt spray, which nature does via ocean waves and wind. MCB mimics natural marine cloud formation, simply giving the climate system a small, targeted tweak by producing smaller sea salt particles that brighten the clouds to increase the level of reflection. rather than introducing any fundamentally new mechanisms.
If monitoring or models detect unexpected effects, the deployment of MCB can be stopped quickly, restoring previous conditions. MCB’s cooling effect also slows ocean evaporation—the main energy source for hurricanes—offering protection for vulnerable coastal regions. Cooling the ocean and reducing evaporation is extremely unlikely to cause any negative consequences.This adaptability provides a hopeful and proactive approach, balancing the unlikely risks of marine cloud brightening against the very real, ongoing disasters of climate inaction.
In short, doing nothing comes at a catastrophic cost, while MCB offers a responsible, targeted, and reversible way to mitigate some of the worst impacts of climate change.
2. How certain is the science behind MCB?
We will monitor everything from space as soon as we start. To make sure the way we understand the science is correct. If it’s not working as intended, we can call it off straight away.
Unlike other interventions, MCB’s effects are visible in days, not years. If there’s a problem, we can stop and nature resets in less than two days. Any salt particles created will be washed out of the clouds very quickly.
3. Does geo-engineering present a moral hazard?
The moral hazard is doing nothing to reduce the impact of the climate crisis. We argue that emission reduction and carbon capture must happen at the same time. Cooling the planet buys us time, not a free pass.
4. What is “termination shock” and how does it relate to MCB?
Termination shock occurs if MCB deployment suddenly stops, which could lead to rapid increases in global temperature.
The way to avoid termination shock is to make sure the emission reduction and carbon capture from the air are implemented. We are committed to that mission as well.
We want to end MCB as soon as emissions drop and carbon is removed.
5. Are MCB operations vulnerable to disruption?
MCB spray vessels operating on open oceans could be exposed to physical disruption but hundreds of vessels will be required and it is unlikely that they would all experience a physical disruption at the same time.
MCB does not have a single point of failure. Its not just one ship. Its hundreds of ships, each doing local cooling, which means one incident won’t halt the mission.
6. How is MCB governed internationally?
Right now, it’s up to individual countries to act in their own waters. We welcome international oversight, but we can’t wait for perfect global agreement while individual countries need help and people suffer.
7. What are the ethical and social justice concerns of MCB?
Our goal is to protect lives, not put anyone at risk. Countries in Asia and Africa need help the most to overcome the damage caused by rich countries emissions.
8. How does public perception affect MCB?
We’re starting with local cooling, not a global experiments. We’ll earn public trust by proving safety and effectiveness step by step.
9. Is MCB economically viable?
MCB costs are tiny compared to the $200 billion lost to extreme weather each year. It’s a bargain for the protection it offers.
10. Will MCB require increasing intensity over time?
We’ll only scale up with public approval and proof of safety. No one’s locked in-unlike the climate crisis, which is already here.
11. Does MCB distract from real climate solutions?
MCB isn’t a distraction-it’s a stopgap. In fact our existence should direct focus to slash emissions and pull carbon from the air. All three are essential.
12. Are MCB risks unpredictable and irreversible?
Our approach is local and reversible. If there’s a problem, we stop, and the effect is gone in under two days.
13. Does MCB require deployment on an unmanageable scale?
Only a small increase in cloud brightness is needed. MCB is a bridge to a future where emissions are cut and carbon is removed. We don’t want to be a longterm venture
14. Could MCB threaten human rights or environmental justice?
Every time temperature rises by just another 0.1˚C, the environment is no longer conducive to human flouring for another 100,000 million people. By now more than 350,000 million people have been deprived of their rights and we would like to help reverse this.
Every tenth of a degree we cool saves millions from un-livable heat. We’ll halt immediately if there’s any sign of harm.
15. Is MCB consistent with international law?
Local cooling isn’t geo-engineering in the traditional sense. We work with nations, not over them.
16. Does MCB legitimise fossil fuel interests?
MCB is a temporary shield, not a license for polluters. The real solution is shutting down fossil fuels and removing carbon.
17. Is there sufficient democratic oversight or global consent for MCB?
We’re not experimenting on the world – we’re offering local solutions, with consent, to restore rights lost to climate change.
18. Could MCB cause geopolitical tensions?
No unilateral action – only local initiatives, and only with consensus. We want cooperation, not conflict.
19. Is there a slippery slope from research to deployment?
Small-scale doesn’t mean inevitable expansion. Every step depends on public support and proven safety.
20. Is the process transparent and accountable?
Our process is open and transparent. We invite scrutiny – something we wish all climate actors would embrace honesty. Where is the transparency of fossil fuel companies and other polluters?
21. Are broader scientific and social perspectives included?
We welcome input from all fields – science, law, ethics, and communities. This is a global challenge, and we need everyone at the table.
22. Could MCB be considered ecocide?
Our aim is to prevent environmental catastrophe, not cause it. If you want to talk about crimes, look at those who let the crisis spiral. Who licensed the fossil fuel companies to exploit oil, when they knew back in the 1970s the damage they would do. Were we consulted before cars were allow on the road to spew out CO2?