A bolt from the blue. Or maybe we should say: heat waves from modified clouds. What seemed like an ingenious trick to cool the US West could turn into a climate nightmare for Europe. Cloud geoengineering, the latest 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 “clearing of marine clouds.” 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 reflected, the less heat absorbed by the Earth. 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, San Diego, he simulated the large-scale application of MCB in the North Pacific. The results? A mix of good and bad news, with the emphasis decidedly on the “bad”. Initially, the MCB seems to be working. The simulations show a reduction 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: drastic reductions in precipitation, not only in the US, but also in remote regions such as the African Sahel. And this is only the beginning.
Our results provide an interesting case study that illustrates the unexpected complexities in the climate system that can be uncovered through regional geoengineering
Jessica Wan, research team member.
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 marred by El Nino. Here, the MCB not only loses its effectiveness in the USA, but unleashes a real thermal inferno in Europe.
The warming we derive from mathematical models is particularly high in Scandinavia, Central and Eastern Europe
Katharine Ricke, University of California, San Diego
How can a change in clouds in the Pacific cause heat waves in Europe? The answer lies in large-scale atmospheric currents. The MCB, by altering these global flows, creates a chain reaction that ripples across the planet. It's the butterfly effect taken to the extreme: a flap of wings in the Pacific triggers a thermal hurricane in Europe. But there's 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, it could discourage action to reduce carbon emissions, producing even more risks for when, after a “brilliant” start, there is an abrupt return to reality.
Geoengineering and heat waves, heated debate
Not everyone agrees with the study's conclusions. daniel harrison from Southern Cross University in Australia, which is studying the use of MCB to mitigate heat waves 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.
Proceed as soon as possible: heat waves are a growing threat. And the history of the MCB teaches us once again that quick solutions based on geoengineering climate change can have unforeseen and potentially catastrophic consequences. In the Earth's complex climate system there are no shortcuts. The real solution to heat waves and climate change requires an approach that respects the delicate balance of our planet. Next time you hear about a silver bullet, remember: In the climate game, trickery can be worse than deception. And heat waves? They may just be the beginning of a much bigger and more dangerous game we are playing with our future.
Notes for you: Small-scale MCB experiments have already been conducted in Australia on the Great Barrier Reef and in San Francisco Bay, California .
