NEW YORK – A fleet of 100 aircraft carrying out 4,000 missions worldwide each year could help save the world from climate change. In addition, it can be relatively cheap. This is the conclusion of a new peer-reviewed study in Environmental Research Letters.
This is the substance of science fiction. Planes spray tiny particles of sulphate into the lower stratosphere, at an altitude of about 60,000 feet. The idea is to help protect the Earth from just enough sun to maintain low temperatures.
The researchers examined how a hypothetical solar geoengineering project would be practical and costly in 15 years. The goal would be to halve the increase in temperature caused by thermal trapping of greenhouse gases.
This method would mimic what big volcanoes do. In 1991, Mount Pinatubo erupted in the Philippines. According to the United States Geological Survey (USGS), it was the second largest eruption of the twentieth century.
The second largest volcanic eruption of this century, and by far the largest eruption affecting a densely populated region, occurred at Mount Pinatubo, Philippines, on June 15, 1991.
USGS
In total, the blowout injected 20 million tonnes of sulfur dioxide aerosols into the stratosphere. The USGS said the temperature of the Earth's lower atmosphere had dropped to about 1 degree Fahrenheit. The effect lasted only a few years because the sulphates eventually fell to Earth.
Although controversial, some believe that trying to replicate the effects of a volcano eruption is a viable way to control global warming. This type of proposed climate geoengineering is called stratospheric aerosol injection (SAI). Theoretically, if done on a large scale – and in a sustainable way – the impact can be significant. The 1 degree temperature drop that accompanied the eruption of Mount Pinatubo equates to about half of the man-made warming on Earth since the beginning of the Industrial Revolution.
In this photo from Climate Central, they explain that scientists are studying various technologies – from capturing carbon dioxide in the air, as trees do, to launching giant mirrors in space – to artificial warming. of the slowdown of the planet.
Document via Climate Central
Dr. Gernot Wagner of Harvard University is the author of this paper. He added that their study shows that this type of geo-engineering "… would technically be possible strictly from the point of view of engineering.It would also be remarkably cheap, with an average of about 2 to $ 2.5 billion a year over the first 15 years. "
But to reach this point, the study indicates that a brand new aircraft must be developed. In part because missions should be conducted at about twice the cruising altitude of commercial aircraft. Co-author of the study, Wake Smith, explained: "No existing aircraft has the combination of altitude capabilities and payload required."
The team therefore sought to know what it would cost to develop an aircraft she named SAI Lofter (SAIL). They say that his fuselage would have a squat design and that the area of the wing – as well as the thrust – should be twice as large. In total, the team estimates that the cell's development costs would be $ 2 billion and $ 350 million to modify the existing engines.
In their hypothetical plan, the fleet would start with eight planes in the first year and increase to just under 100 in 15 years. The first year, there would be 4,000 missions, to reach a little over 60,000 a year from the fifteenth year. As you can see, this effort should be supported and intensified.
As one can imagine, such a concept is very controversial. Just like treating a fever with aspirin, this type of engineering only treats the symptoms, it does not solve the root cause of the warming: increasing levels of heat trapping gases to greenhouse effect produced by burning fossil fuels.
The American Meteorological Society (AMS) has expressed concern that the possibility of seemingly quick and inexpensive solutions would prevent the public and policymakers from tackling the underlying problems and problems. Develop adaptation strategies. And if, for some reason, the aerosol missions stopped, in a few years, temperatures would increase at breakneck speed. A pace that would probably be too fast for humanity to adapt.
The official statement of AMS policy regarding this type of geoengineering begins with a warning: "Reflection of sunlight would likely reduce the average temperature of the Earth, but could also change global circulation patterns with consequences potentially serious, such as changes in the trajectories of storms and precipitation. "
In other words, the atmosphere is complex. Any dressing patch is bound to have unintended consequences and possibly cause a new set of problems. The AMS goes on to assert that the results of the sun's reflection "would certainly not be the same for all nations and all peoples, thus raising legal, ethical, diplomatic and national security concerns". An area can become a desert, while others are flooded.
And if we learn to control SAIs in order to tailor a favorable outcome, we fear that it will be used for the disproportionate benefit of one nation over another. In a 2017 study in the Nature Communications publication, the authors warn their work "… again puts the spotlight on the dangers of unilateral geoengineering, which might interest individual actors because of". greater controllability of local climate responses, but with additional risk elsewhere. "
But perhaps the biggest reason for being skeptical about the management of sunlight spray is that it is not a quick fix. As carbon dioxide continues to increase, the oceans are becoming more and more acidic. According to NOAA, ocean acidification can spread into the ocean food web, reducing the ability of coral shells and corals to produce their skeletons. The injection of aerosols into the stratosphere simply limits the sunshine, but does not attack the accumulation of underlying carbon dioxide. The ocean would continue to acidify.
Despite the potential drawbacks, the AMS recognizes – even with aggressive mitigation measures – that some of the dangerous consequences of climate change already cooked in the system. In addition, the extent of human adaptation is limited. Therefore, they call for caution and further research.
The AMS policy statement ends with: "Geoengineering will not replace aggressive mitigation or proactive adaptation, but could contribute to a comprehensive risk management strategy aimed at slowing the pace of change. The potential to help society cope with climate change and the risks of adverse consequences imply the need for adequate research, appropriate regulation and transparent deliberations. . "
