A Harvard University research group he thinks it might be possible to achieve a temporary reduction in global temperatures by changing the composition of the earth’s upper atmosphere.
The researchers hoped to test some of that technology – and the feasibility of their theory – in what they call it Stratospheric Controlled Perturbation Experiment (SCoPEx), this summer.
Although the work has been temporarily suspended, the team still hopes that the experiment can go on in the not too distant future, however a question naturally arises, what is it about?
In 2021, the Earth reached a bleak milestone, the concentration of carbon dioxide (CO2) in the atmosphere has reached the 150% of its value in pre-industrial times -according to Met Office of the United Kingdom – and, to prevent the worst effects of climate change, the world must reduce net carbon dioxide emissions to zero by 2050.
But even if we succeeded in achieving this, we would not suddenly put a stop to the rise in temperature, because it takes time to see the effects of CO2 reductions on global temperatures, in fact the negative impacts of global warming will continue for decades.
So, is there anything else we can do to reduce temperatures faster?
The ultimate source of Earth’s heat is the sun, which radiates the diurnal part of the planet in a constant stream of infrared radiation, with about 30% of this being reflected back into space by the atmosphere, while the rest heats the planet during the day. and is radiated into space at night.
In the delicate balance that prevailed in pre-industrial times, the incoming heat was exactly compensated by the amount lost in space, ensuring that global average temperatures remained constant.
The problem today is that CO2 emissions disrupt this balance by absorbing some of the heat that should be radiated into space, trapping it within the atmosphere.
The more carbon dioxide there is in the atmosphere, the more the temperature rises and, in the long run, humans must reduce the amount of carbon dioxide in the atmosphere to prevent the worst effects of climate change, however the project SCoPEx could produce short-term reductions in global temperature.
In addition to SCoPEx, there are also natural events, for example the volcanic eruptions, which cause clouds of dust particles to explode high in the stratosphere, an upper layer of the atmosphere, forming a protective shield which prevents some of the sun’s heat from reaching the earth’s surface.
L’1991 eruption of Mount Pinatubo in the Philippines, for example, caused a drop in average temperature in the Northern Hemisphere about 1 degree Fahrenheit (more than half a degree Celsius) over the next 15 months, and that’s exactly what the SCoPEx team wants: to take a page from such eruptions by injecting particles into the upper atmosphere to lower temperatures.
How the SCoPEx project should work
The basic idea, called stratospheric aerosol injection, or YOU KNOW, it’s simple, it’s a high-flying airplane, or a helium balloon, that would deliver batches of microscopic particles called aerosols into the stratosphere at altitudes of 12.4 miles (20 kilometers) or more, much higher than those of planes usually fly.
The aerosols would remain suspended in the air, too small to be visible as clouds from the ground but opaque enough to reflect a fraction of the solar energy back into space.
In simulations, SAI appears to be a viable concept, Furthermore a report from 2018 ofIntergovernmental Panel on Climate Change (IPCC) found that a high-altitude fleet of aircraft could deposit enough aerosols to offset current levels of global warming.
However there is a big one though, aerosols should indeed be replenished every few years and the method only addresses one of the symptoms of climate change, but does not address the root cause, which is the greenhouse effect.
At best, it is an interim measure, which counteracts rising temperatures as countries simultaneously reduce carbon dioxide levels, moreover to date, the research on the SAI was theoretical, complemented by a limited amount of real data from volcanic eruptions.
SCoPEx wants to make real-world measurements under carefully controlled conditions, enabling better calibration of computer models:
“If we want to provide decision makers with useful information on whether this will work, we need to confirm our models”
he told al Boston Globe the principal researcher of the SCoPEx project, Frank Keutsch, of the Harvard University Department of Chemistry and Chemical Biology.
Volcanoes mainly emit sulfur-based compounds, but these compounds not only cool the atmosphere, but also damage the Earth’s protective ozone layer, which protects us from harmful UV radiation.
The SCoPEx team is focusing on a less harmful aerosol, the calcium carbonate – in other words, chalk dust – that the researchers hope for it will produce the desired cooling effect without damaging the ozone layer.
The team wants to field a large unmanned helium balloon that would be similar to a standard weather balloon, except that it would be equipped with propellers to allow the ground crew to maneuver it in a controlled manner and, with the assistance of the Swedish Space Corporation, scientists were planning to launch the balloon near Kiruna, Sweden.
During its first flight, tentatively planned for next year, the balloon will not release anything into the stratosphere, instead it would rise to an altitude of 12.4 miles, where the SCoPEx team would test the maneuvering system and verify that all scientific instruments and communications are functioning properly.
If the test flight were to be successful, a second flight would make a controlled release of 2.2-4.4 pounds (1-2 kilograms) of calcium carbonate at the same altitude.
The balloon would constantly move in a straight line during release, then the aerosol particles would form a narrow plume about 1km in length, with the balloon then returning back through the plume, observing how the particles disperse over time and measure. in which they reflect sunlight, at least according to what is written on the SCoPEx website.
As valuable as the SCoPEx test flight would be to our understanding of SAI, it is important to see the project in perspective.
“The goal is not to change the climate or even see if it is possible to reflect sunlight, the goal is simply to improve our models of how aerosols form in the stratosphere”
previously told a HowStuffWorks one of the SCoPEx project scientists, David Keith, professor of applied physics at Harvard.
Keith himself further states that at least another decade of research will be required before a large-scale aerosol release, which could involve the injection of approx 1.5 million tons (1.4 million tons) of aerosols in the stratosphere per year, with about a hundred aircraft that would need to continuously fly payloads up to about 20 km of altitude.
Not all of them support SCoPEx and SAI
However, SAI remains highly controversial. One concern is that humans created the climate crisis by primarily pumping greenhouse gases into the atmosphere, so how can people be sure that pumping aerosols into it will make things better?
Although computer modeling suggests that SAI is safe, there is still the possibility that it can have unexpected side effects, there is in fact the possibility that it can disrupt weather patterns, damage crops by reducing the amount of sunlight they receive, and if sulfide aerosols are used, damage the ozone layer.
Indeed, some scientists are wary of following the SAI route.
“[…] that we could actually try to control the whole climate is a pretty terrifying idea “
he told Smithsonian magazine, Douglas MacMartin, a research associate and lecturer in mechanical and aerospace engineering at Cornell University and a professor of mathematics and computer science at the California Institute of Technology,.
The IPCC itself, in a 2018 discussion on what the panel called solar radiation modification (SRM), concluded that:
“the combined uncertainties, including technological maturity, physical understanding, potential impacts and governance challenges, they limit the ability to implement SRM in the near future. “.
Due to these concerns, the SCoPEx team has postponed the maiden voyage of its helium balloon until it is possible to conduct a more in-depth social engagement process to address issues related to solar geoengineering research in Sweden.
Keith however argued that the real danger lies in some nonconformist organizations implementing SAI without the kind of scientific data SCoPEX wants to obtain.
The second major objection to SAI research is that governments and companies that are already reluctant to reduce carbon dioxide emissions will cling to SAI as proof that such reductions are unnecessary, and this situation could negate any potential benefits of SAI, even because if the SCoPEx mission is successful and SAI is fully implemented, it will only complement, not replace, the reduction of carbon dioxide.
Lizzie Burns, CEO of Harvard’s Solar Geoengineering Research Program, offered a vivid analogy in this regard, which sums it all up in a few but very valid words:
“It’s like a pain reliever. If you need surgery and are taking pain medication, it doesn’t mean you don’t need surgery anymore. “
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