A bolt from the blue. Or maybe we should say: heat waves from modified clouds. What seemed like an ingenious trick to cool the American West could turn into a climate nightmare for Europe. Cloud geoengineering, the last frontier in the fight against global warming, hides a dark side that we are only now beginning to understand. The technique in question is called Marine Cloud Brightening (MCB), or “sea cloud stripping”. I told you about it some time ago in this article. The idea is simple: inject sea salt particles into the atmosphere to make clouds brighter and more reflective. The more light is reflected, the less heat the Earth absorbs. What could go wrong? A recent study has highlighted potential side effects that would make even the most optimistic geoengineers pale.
When the patch is worse than the hole
The team led by Katharine Ricke from the University of California at San Diego, he simulated large-scale application of MCB in the North Pacific. The results? A mixture of good and bad news, with a decidedly emphasis on the “bad”. At first, the MCB seems to work. The simulations show a discount of up to 55% of the risk of heat waves in parts of the western United States. Victory? Not exactly. The price of this localized cooling is high: a drastic reduction in precipitation, not only in the United States, but also in remote regions like the African Sahel. And that’s just the beginning.
Our results provide an interesting case study that illustrates the unexpected complexities of the climate system that can be uncovered through regional geoengineering.
Jessica Wan, member of the research team.
2050: Europe becomes a sauna
The real bombshell comes when the researchers project their model into 2050, in a scenario of global warming of 2°C spoiled by El Nino. Here, the MCB not only loses its effectiveness in the United States, but triggers a real thermal hell in Europe.
The warming we infer from mathematical models is particularly high in Scandinavia, central and eastern Europe.
Katharine RickeUniversity of California, San Diego
How can a change in clouds in the Pacific cause heat waves in Europe? The answer lies in large-scale air currents. The MCB, by modifying these global flows, creates a chain reaction that reverberates throughout the planet. This is the butterfly effect taken to the extreme: a flap of wings in the Pacific triggers a thermal hurricane in Europe. But there is more. Ricke raises another concern: that of the so-called “lock-in.” If countries begin to rely on these techniques while they are still effective, this could discourage measures to reduce carbon emissions, leading to even more risks when, after a “brilliant” start, there would have a brutal return to reality.
Geoengineering and heatwave, heated debate
Not everyone agrees with the study’s findings. Daniel Harrisson from Southern Cross University in Australia, who is studying the use of MCB to mitigate heatwaves in the Great Barrier Reef, calls the modeled scenarios “completely unrealistic and extreme.” John Moore from the University of Lapland in Finland highlights the urgent need for further research into solar geoengineering. Impacts on low-income countries and indigenous peoples in the Arctic are just some of the issues that require in-depth analysis.
Act as soon as possible: heat waves pose a growing threat. And the story of the MCB teaches us once again that quick fixes based on geoengineering climate change can have unintended and potentially catastrophic consequences. In Earth’s complex climate system, there are no shortcuts. The real solution to heatwaves and climate change requires an approach that respects the delicate balance of our planet. The next time you hear about a silver bullet, remember: in the climate game, trickery can be worse than deception. What about heat waves? They may be just the beginning of a much larger and more dangerous game we are playing with our futures.
