The cost saved by the carbon kept in the permafrost alone would easily cover the cost of doing geoengineering by stratospheric aerosol injection, shows new research from Finnish and Chinese researchers, published in Nature Communications.

The research is led by professor John Moore of Arctic
Centre, University of Lapland. In the study the group considered the change in
Arctic permafrost over the next 50 years using a specific permafrost carbon model
called “PInc-PanTher”.

In particular the researchers looked at a
scenario that is similar to the agreements reached on emissions at Paris (RCP4.5),
and a geoengineering scenario called G4 which specifies injection of sulphate
aerosol into the stratosphere equivalent to one quarter of that from the 1991 Mt.
Pinatibo volcano, for 50 years beginning in 2020.

The aerosol
reduces the solar radiation warming the surface partially balancing increases in
greenhouse gasses, keeping the surface cooler. The temperatures and the permafrost
carbon model predict losses of carbon at both CO2 and methane from much of the
Arctic permafrost over the next 50 years. The amount of greenhouse gases are
released are roughly halved with geoengineering. “Of course the released carbon
increases the greenhouse warming further accelerating permafrost melting”, says
Professor Moore.

“We used an economic model to assess what the
difference in costs from the carbon released from the permafrost would be for the
global economy”, he says. The economic benefits by avoided keeping the carbon in the
permafrost by the year 2069 would be about US$ 0.6 trillion per year, which even
though enormous amounts to only about 1/20 to 1/25 of the total damage from
warming.

The implementation costs of the doing this kind of
geoengineering range from about US$0.05 trillion to US$0.4 trillion. “In other
words, it might well cost less than the savings due only to permafrost carbon
feedback”, says Moore.

“No one is advocating doing geoengineering
on these results alone. They do though illustrate the kinds of impacts warming will
have on different parts of the earth system. There may be some terrible consequences
of doing geoengineering that we just don’t know about yet, but the consequences of
even the mitigation efforts agreed at Paris will be bad enough to make Covid19 seem
like a hiccup”, Moore comments.

The article “Mitigation of Arctic
permafrost carbon loss through stratospheric aerosol
geoengineering” is published in the Nature
Communications on the 15^th May
2020.

Additional information:

Professor John Moore, Arctic Centre, University of Lapland

john.moore.bnu@gmail.com

tel. +358 400 194 850

The
cooling effect of geoengineering and projected soil carbon loss. Ensemble mean
spatial distributions of (a) permafrost soil temperature change in the upper 3 m of
soils between 2020 and 2069 under the emission scenario RCP4.5 and the
geoengineering experiment G4, as well as the difference (G4 – RCP4.5), derived from
the soil surface temperature outputs of 7 climate models after bias-correction and
(b) permafrost soil C loss from PInc-PanTher between 2020 and 2069, integrated from
surface to 3 m depth. By combining the compiled soil carbon maps with laboratory
incubation syntheses, PInc-PanTher provides data-constrained estimates on the
permafrost C response to imposed climatic warming