According to a researcher, climate engineering needs to have a comprehensive view

Of all the possible methods to combat anthropogenic climate change designed so far, climate engineering is one of the least studied.

A generic term for large-scale projects aimed at disrupting the Earth's carbon cycle or radiation budget, climate engineering has only recently been included in the debate on methods of mitigating emissions damage. of carbon.

Research on various climate engineering projects has progressed, but according to Nadine Mengis, a Horizon Postdoctoral Fellow at Concordia's Matthews Climate Lab until March 2019, too few studies to date have examined large-scale side effects of these projects. would have on the interconnected variables.

In a new article published in the journal Climate changeMengis examines the possible disruption of relations between many of what she calls "Earth system variables" – the aspects of the climate that are not the direct target of engineering projects will nevertheless be affected. – caused by three different techniques of climatic engineering methods.

The big three

Mengis, who changed his affiliation at Simon Fraser University this winter but has completed his research for this article at Concordia, examined three proposed climate engineering methods for his study. Here's how each works, in very general terms:

First, the management of solar radiation. This consists of adding aerosols into the stratosphere that would disperse incoming sunlight and block some of the energy that would otherwise enter the Earth's system. Think of it as if you were imitating the effects of a volcanic explosion.

"In an undisturbed or unmanaged climate, the temperature will increase because of the increase in CO2 concentrations," she says. "But if we manipulate the planet's radiation budget, temperatures would stabilize or fall, while CO2 levels would remain unchanged."

The second is the improvement of the alkalinity of the oceans. This involves grinding huge amounts of rocks and dumping them into the surface ocean, where they would absorb carbon dioxide by chemical reaction.

This would result in an increase in ocean alkalinity – the ability to neutralize acids – and eventually an increase in oceanic pH, indicating lower acid levels. However, to be effective, Mengis estimates that millions of tons of rocks should be crushed and dumped into the ocean. By today's standards, it's not just unachievable; immersion at sea is also illegal.

The third is large-scale afforestation. As its name suggests, it is the extreme opposite of deforestation – but does not stop at planting millions of trees.

Since trees only absorb large amounts of carbon during their growth, says Mengis, these trees should be planted, harvested and sequestered in the carbon they contain. The cycle should be repeated constantly to be effective and would require, according to some estimates, the reforestation of an area the size of Europe.

She is of course aware that none of these measures is possible to implement in the immediate future, but she notes that these estimates are based on current emission rates. If humans reduce their emissions dramatically, some of these measures could be implemented on a smaller scale.

The problems and solutions are global

Mengis points out that research on climate engineering methods remains far too narrow and is therefore of limited value for informed decisions to be made.

"I think we're skipping several steps," she says. "There are some issues that we need to look into before going into details such as how climate engineering can help crop yields."

She hopes that the scientific community will use her article as an orientation to study the side effects that these projects may have in a more holistic and holistic way. As for the audience, she hopes they will understand that the field is still relatively young.

"There are still a lot of unknown unknowns," she says. "Things we do not even know yet could be impacted, and I hope my paper sheds some light on that."