Los científicos dicen que volver a congelar los polos de la Tierra es posible y muy barato

Los polos de la Tierra se están calentando varias veces más rápido que el promedio global. De hecho, a principios de este año se reportaron olas de calor sin precedentes tanto en el Ártico como en la Antártida. El derretimiento del hielo y el colapso de los glaciares en latitudes altas aceleraría el aumento del nivel del mar en todo el planeta. Afortunadamente, sería notablemente factible y económico volver a congelar los polos reduciendo la luz solar entrante. Eso es según una nueva investigación publicada el 15 de septiembre de 2022 en IOP Publishing’s Comunicaciones de investigación ambiental.

Los científicos han ideado un posible programa futuro de geoingeniería en el que los chorros a gran altura rocían partículas de aerosol microscópicas en la atmósfera en las latitudes 60 grados norte y sur, aproximadamente Anchorage y el extremo sur de la Patagonia. Si se inyecta a 43 000 pies/13 000 metros (por encima de las altitudes de navegación de la aeronave), estos aerosoles se desplazarán lentamente hacia el polo, sombreando ligeramente la superficie debajo.

El autor principal, Wake Smith, señala: “Existen preocupaciones generalizadas y razonables sobre los despliegues de aerosoles para enfriar el planeta, pero si la ecuación riesgo/beneficio va a dar sus frutos en algún lugar, es en los polos”. profesor Smith en[{” attribute=””>Yale University and a Senior Fellow at the Mossavar-Rahmani Center for Business and Government at Harvard Kennedy School.

Particle injections would be performed seasonally in the long days of the local spring and early summer. Both hemispheres could be serviced by the same fleet of jets, ferrying to the opposite pole with the change of seasons.

A tabular iceberg floating within Paradise Harbour, Antarctica. Credit: IOP Publishing

Pre-existing military air-to-air refueling tankers such as the aged KC-135 and the A330 MMRT don’t have enough payload at the required altitudes. However, newly designed high-altitude tankers would prove much more efficient. A fleet of roughly 125 such tankers could loft a payload sufficient to cool the regions poleward of 60°N/S by 2°C per year. This would be enough to return them close to their pre-industrial average temperatures. Annual costs are estimated at $11 billion. This is less than one-third the cost of cooling the entire planet by the same 2°C magnitude and just a tiny fraction of the cost of reaching net zero emissions.

“Game-changing though this could be in a rapidly warming world, stratospheric aerosol injections merely treat a symptom of climate change but not the underlying disease. It’s aspirin, not penicillin. It’s not a substitute for decarbonization,” says Smith.

Cooling at the poles would provide direct protection for only a small portion of the planet. However, the mid-latitudes should also experience some temperature reduction. Since less than 1% of the global human population lives in the target deployment zones, a polar deployment would entail much less direct risk to most of humanity than a global program.

“Nonetheless, any intentional turning of the global thermostat would be of common interest to all of humanity and not merely the province of Arctic and Patagonian nations,” adds Smith.

In summary, the current study is just a small and preliminary step towards understanding the costs, benefits, and risks of undertaking climate intervention at high latitudes. It provides further reason to believe that such tools could prove useful both in preserving the cryosphere near the poles and slowing global sea level rise.

Reference: “A subpolar-focused stratospheric aerosol injection deployment scenario” by Wake Smith, Umang Bhattarai, Douglas G MacMartin, Walker Raymond Lee, Daniele Visioni, Ben Kravitz and Christian V Rice, 15 September 2022, Environmental Research Communications.
DOI: 10.1088/2515-7620/ac8cd3