I følge ny forskning vil det å fryse polene på nytt ved å redusere innkommende sollys både mulig og bemerkelsesverdig billig.
Jordens poler varmes opp flere ganger raskere enn det globale gjennomsnittet. Faktisk ble det rapportert om rekordstor hetebølger tidligere i år både i Arktis og Antarktis. Smelting av is og kollapsende isbreer på høye breddegrader vil akselerere havnivåstigningen rundt planeten. Heldigvis ville det være både gjennomførbart og bemerkelsesverdig billig å fryse polene på nytt ved å redusere innkommende sollys. Dette er ifølge ny forskning publisert 15. september 2022 i IOP Publishing’s Miljøforskningskommunikasjon.
Forskere la ut et mulig fremtidig geoingeniørprogram der høytflygende jetfly ville sprøyte mikroskopiske aerosolpartikler inn i atmosfæren på breddegrader 60 grader nord og sør – omtrent Anchorage og sørspissen av Patagonia. Hvis de ble injisert i en høyde på 43 000 fot / 13 000 meter (over passasjehøyder), ville disse aerosolene sakte drive mot polen og skygge overflaten litt under.
“Det er utbredt og fornuftig frykt for å utplassere aerosoler for å kjøle ned planeten,” bemerker hovedforfatter Wake Smith, “men hvis risiko/nytte-ligningen skulle lønne seg hvor som helst, ville det vært ved polene.” Smith er foreleser ved[{” 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