Climate mitigation strategies

(MAINSgs3:Conservation, environmental pollution and degradation, environmental impact assessment.)

Context:

In a controversy late last year, a private venture called Make Sunsets released tiny amounts of sulphur dioxide into the stratosphere using balloons in an effort to sell ‘solar-dimming’ as a way to offset carbon emissions.
To many researchers the event was a major red flag signalling the colonisation of common goods like the atmosphere by private players.

Cooling the air:

A sufficiently powerful volcanic eruption can spew sulphates and other aerosols into the stratosphere, cooling the air there.
This fact has motivated human efforts to artificially spray aerosols into the stratosphere to slow global-warming, with occasional support from the U.S. government, among others.
Researchers from the U.S. have proposed that billions of tonnes of dust can be launched from the moon to a Lagrange point – a point in space where the earth’s and the Sun’s gravitational fields cancel each other out.

Year without summer:

The science of the consequences of volcanic eruptions is well-established as aerosols in the stratosphere, especially radiation-scattering ones such as sulphates, do have a cooling effect.
This is what led to the ‘year without summer’ – but it would be unwise to forget the other consequences of the same eruption.
The cool summer led to widespread drought across the planet, sent crop yields plummeting, leading to disease and starvation.
Many climate models have confirmed that dimming the amount of incoming sunlight with stratospheric aerosols will have similar outcomes.

Temperature response:

Some recent studies have argued that the resulting drought won’t be as harmful and that the GDPs of most countries will be positively affected by this approach to SRM.
But we should remember that even state-of-the-art climate models are skilled only at guessing the temperature response to changes in solar radiation caused by changes in the concentrations of greenhouse gases and stratospheric aerosols.
In addition, these temperature projections are best at the continental scale – not at the regional scale, which matters when it comes to heatwaves, drought, and such.
Any projections related to changes in rainfall, as a result of throwing up dust into the atmosphere or in space to block sunlight, will be highly uncertain.

Mitigation strategies:

We need to bear in mind the fortunes of the Global South, which may once again be an innocent bystander to large-scale experiments by the Global North.
Other climate mitigation strategies, such as the use of renewable energy, emissions reductions schemes, carbon-capture technologies, and bioenergy, are not expected to have any dangerous unintended consequences.
On the the hand, spraying aerosols even in a small pocket of the stratosphere will have global consequences that we can’t fully quantify at present.

Way forward:

Many natural as well as social scientists have expressed grave concerns about the science and governance issues of SRM.
The University of Oxford and the Asilomar Conference have proposed guiding principles for attempts to geoengineer the climate.
Some points: Those involved must clearly and explicitly report the science and technology of these approaches along with their consequences – the good, the bad, and the ugly.
The governance of the deployment and monitoring, verification, and reporting should be democratic and inclusive.
And stakeholders must codify and preemptively agree on compensation mechanisms for any harm.