The heat is on. Average temperature increases don’t tell the whole story and while global average temperature increases now exceed 1.1°C, in the Arctic it exceeds 5.5°C.

Beyond a certain tipping point, global warming will become an ever-accelerating, irreversible reaction.

MCB is a form of mild cloud management, the elegance of this is that it mimics sea spray to brighten the appropriate clouds, thus increasing the reflectivity. They can mirror more sunlight back into space, allowing the areas underneath these clouds to become cool enough to refreeze the Arctic.

It’s all about reflectivity; the albedo.
Powerful positive feedback loops explain the dramatic temperature rise in the Arctic. As the bright, white Arctic ice cap - with a high albedo of about 1.0 - melts as a result of global warming, it exposes the dark water on which it floats. This dark water has a low albedo of about 0.1, absorbing more heat from the sun. This leads to a warmer sea, causing ice caps to melt and more exposure to dark water. Furthermore, and as an additional result of global warming, the currents flowing to the Arctic have also become warmer.

The Arctic ice cap has entered into a ‘spiral of death’.

Does it matter?

The Arctic ice cap acts as a refrigerator for the planet. The loss of this refrigerator will accelerate global warming.

The Arctic ice cap acts as a mirror, reflecting the sunlight. The loss of this mirror will accelerate global warming.

Contrary to popular belief, the loss of the Arctic ice cap won’t contribute significantly to sea-level rise. The expansion of oceans, however, due to warmer sea, most certainly will.

Letting the ice cap disappear will have further dramatic consequences:

  1. The loss of the Greenland ice cap; if the whole of the Greenland ice cap melts, sea levels will rise by about 7m. Even a partial melt of this ice cap will threaten all coastal regions.
  2. The release of methane, a very potent greenhouse gas, into the atmosphere was, until now, safely locked away in the permafrost.
  3. The collapse of ocean currents as we know them.

On top of substantially accelerating global warming, the loss of the Arctic ice cap will have another 3 major consequences for the planet, which constitute existential threats:

  1. The Greenland ice cap is melting at an alarming pace. In 2021, for the very first time, instead of snowing, rain fell at Greenland’s summit as a result of warmer-than-usual summer temperatures. If the ice cap over Greenland melts, sea-water levels worldwide will rise by 7m. The speed at which the Greenland ice cap melts is constantly accelerating as a result of the Arctic positive feedback loops. To make matters worse, the Greenland ice cap’s albedo is diminishing due to soot deposits and algae growth. The soot deposits originate from the exhausts of engines and smokestacks of factories burning fossil fuels. The algae growth is triggered by global warming. Both effects markedly reduce the Greenland ice cap’s reflective power, allowing for further melting.
  2. Due to the rapid and dramatic warming of the Arctic region, the Siberian permafrost is melting, with the danger that it will release massive amounts of underground methane into the atmosphere. Methane is about 40 times more powerful than carbon dioxide. Until now, this methane has been safely locked away.
  3. As the seas around the Arctic warm up, the difference in temperature between the cold Arctic seawater and the warmer Atlantic seawater flowing into the region diminishes. It is this temperature difference which drives the existing pattern of ocean currents, with the most important being the Atlantic Meridional Overturning Circulation (AMOC). If the AMOC collapses because this temperature difference diminishes, the consequences will be dramatic.

Contrary to many other techniques grouped under the umbrella of ‘solar radiation management’, MCB has no apparent disadvantages: it can be applied locally, it does not use ‘foreign agents’, it does not seem to cause collateral damage, it can be switched on or off almost instantly, it can be deployed at scale at relatively low-cost, it promises enough cooling to temporarily halt the loss of the Arctic ice cap, and it could be available within a short timeframe.

Counter-intuitively, MCB might be most effective:

  1. In regions where low-lying cumulus nimbus aggregate (e.g. off the coast of Namibia).
  2. Above the Atlantic currents carrying warm sea water to the Arctic.

MCB might even be applied at smaller scale in situations needing local cooling (e.g. The Great Barrier Reef).