on October 16th, 2019

Climate change remains one of the biggest problems our world has ever faced, and there are no signs that it will drastically improve any time soon. So engineers and scientists are coming together to investigate a controversial technique to prevent an environmental catastrophe.

Geoengineering may seem like something from a far-fetched science fiction film, with ideas ranging from mirrors in the ocean to reflect sunlight away from earth to space sunshades. However, engineers are now investigating the notion of releasing millions of tons of sulfur dioxide into the stratosphere as a potential solution to reducing the effects of climate change. The idea behind this is the particles will reflect sunlight away from earth and therefore cool the planet.

The notion originated from the eruption of Mount Pinatubo in 1991. This volcano in the Philippines erupted, spewing fifteen to seventeen million tons of white ash and sulfates up to ten kilometers into the sky. Fifteen months later, scientists combing over the data realized the particle cloud had shielded the area from the sun, with temperatures dropping by 0.6 degrees Celsius.

The idea is that aircraft will spray sulfate particulates into the lower stratosphere at 60,000 feet. The process would theoretically be equal to a volcano ejecting sulfates into the sky during an eruption. The sulfur dioxide shot up into the stratosphere forms sulfuric acid drops, which then rotate around the globe for 48 months, and successfully hinder sunlight from penetrating it. The result could be a one-degree temperature drop, which would reverse the global temperature rise of the last century.

This technique, known as stratospheric aerosol injection, is considered radical and opposed by many as they believe the effects of intentionally modifying the climate could be worse than climate change itself. In fact, in 2018, the Global Challenges Foundation published a report on major threats against humanity — and solar geoengineering was listed as one of these, as was catastrophic climate change.

At the Paris Climate Conference in 2015, governments around the world acknowledged that something needed to be done to accelerate anti-global warming effects.  They set out several targets, including keeping the global temperature rise this century well below two degrees Celsius above pre-industrial levels. The deal was ratified in 2016; however, the issue remains that governments across the world are realizing they are still not on track to achieving the initial targets set out in the Paris Agreement.

This is why some scientists see geoengineering as a legitimate solution to saving our planet. The Global Challenges Foundation report explains the appeal and the risks.

“Solar geoengineering is the only known technique for quickly stopping or even reversing the rise in global temperatures. Although it does not solve the root cause of climate change, it could be used to reduce the length or the magnitude of a temperature overshoot (beyond the Paris goal) during the transition period needed for massive decarbonization at the global level or provide insurance against a potential ‘climate emergency.’

“However, we don’t know enough about the risks and potential benefits of the technology, and it carries considerable risks – in particular, it may destabilize local and global climate, as well as various elements of the global ecosystem. In addition, a sudden termination of solar geoengineering would lead to rapid and severe global warming, with no time for natural and social systems to adapt.”

The reality is that carbon emissions must be reduced urgently because things will only get worse. The report states that if the temperatures increased by three degrees Celsius, most of Bangladesh and Florida would drown. Other coastal cities would also be flooded, which would then create hundreds of thousands of climate refugees across the world.

As a result, a team of scientists at Harvard University is hoping to implement the first in situ geoengineering experiment to determine whether it is a viable solution. However, they are facing critics who worry that once we start experimenting with these radical ideas, we will be heading down a slippery slope.

To appease those with fears about the result of this experiment, Harvard University has put together an advisory committee to ensure that appropriate steps are taken to mitigate health and environmental risk and ensure they operate transparently.

Scientists first proposed the experiment in 2014. It will see researchers launch a scientific balloon with sensors and propellers 20 kilometers above the earth. They will release between 100 grams and two kilograms of calcium carbonate particles in a kilometer-long plume. This is limestone dust and is less likely to deplete the ozone layer than sulfates.

The balloon will fly through the plume, and its sensors will measure how far the particles scatter, how they interact with other compounds in the atmosphere, and how much light they reflect.

The project’s principal investigator Frank Keutsch explained in a statement that they hope this experiment will inform the feasibility of geoengineering.

“If anything, I’m concerned that the current climate models make solar geoengineering look too good. If we want to be able to predict how large-scale geoengineering would disrupt the ozone layer, or the exchange of air between the troposphere and stratosphere, we need more real-world observations.”

The Carnegie Climate Governance Initiative’s Janos Pasztor is one scientist who has concerns about geoengineering experiments. Such worries include the technology affecting ocean circulation, biodiversity, disease patterns, agriculture, and causing extreme weather.

The Union of Concerned Scientists’ climate and energy program’s Shuchi Talati, echoed these sentiments.

“We don’t know what the regional impacts will be,” Dr Talati said.

“There have been different modeling papers showing different things.”

The other major issue is that a global thermostat will need be set to determine a particular global thermal temperature, creating winners and losers. While one region might experience favorable rainfall to help its agricultural industry thrive, another nation might experience devastating drought. There are now fears surrounding security risks, because who gets to control this global thermostat and what happens if it gets breached or hacked?

Mr Pasztor argues that because this technology is cheap enough to be accessible to virtually every country, the fact that it is ungoverned could have horrific political consequences.

“Imagine a situation where China unilaterally goes ahead, and a couple of years later the monsoon fails in India, and lots of people starve, “ he said.

“Even if you cannot link the failure of the monsoon to the stratospheric aerosol injection activity, people in India might think it’s because of the Chinese.”

Mr Pasztor helped advise on the Paris Agreement and emphasized that geoengineering should not be used to replace cutting emissions, but as insurance in case we do not meet our temperature goals. Other scientists fear that an overreliance on geoengineering will undermine efforts to reduce greenhouse gases.

In a previous news article, we covered what engineers could do to help save the planet. These other geoengineering solutions included marine cloud brightening that would see naval ships spraying salt particles into the air, in turn brightening the clouds hanging over the sea. The brightened clouds would also deflect the sun off the earth.

Many of these advents of carbon mitigation and climate geoengineering have certain checks and balances that slow the process of their implementation. And that is perhaps a good thing. Attempting to engineer the climate raises ethical and political issues. Not to mention, scientists must conduct the experiments in the safest possible ways. However, it is encouraging to see that scientists and engineers are rising to the occasion to combat oncoming climate events that could save thousands, if not millions of lives.


Works Cited

Salleh, Anna. “A Planet-Sized Sunshade? It Sounds Far-Fetched, but Some Scientists Are Seriously Considering It.” ABC News, Australian Broadcasting Corporation, 24 July 2019, www.abc.net.au/news/science/2019-07-24/climate-hacking-to-avoid-a-global-warming-apocalypse/11300460

Temple, James. “Geoengineering Is Very Controversial. How Can You Do Experiments? Harvard Has Some Ideas.” MIT Technology Review, MIT Technology Review, 29 July 2019, www.technologyreview.com/s/614025/geoengineering-experiment-harvard-creates-governance-committee-climate-change

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