We have technology. The planes could spray particles into the atmosphere to combat climate change. But should we?

If the patterns of climate change are correct, humanity works itself and drags the rest of life on Earth in a corner. Scientific means to control emissions and combat climate change are beginning to have an effect, but not enough. So now we have hard decisions to make.

If you have not heard the terms "solar geoengineering" and "stratospheric aerosol injection", you should probably get used to it. They represent a scientifically and technologically realistic plan for controlling climate change when all other models of governance and economics can not do it. The idea has existed for some time, but considered too expensive in the past.

Now, a new research paper in Environmental Research Letters analyzes what should be used to use planes to spray sulphates into the stratosphere to cool the climate. The two authors are Wake Smith of Yale and Gernot Wagner of Harvard. And once you have exceeded your surprise, the document presents well-thought-out parameters for the entire company.

"… a hypothetical deployment program in 15 years, … would be technically possible strictly from an engineering point of view." – Dr. Gernot Wagner, co-director of the Harvard Solar Geoengineering Research Program.

First, let's dispel some myths. This has nothing to do with the sun's attenuation, chemtrails or control of the mind. Mankind can not darken the sun. Chemtrails are ignorant fever dreams, and mind control is just … it does not matter. Smith and Wagner are serious people and deserve to be taken into account.

Wagner is an associate researcher and lecturer at Harvard, co-director of Harvard's solar geoengineering research program and author of the book Climate Shock. Smith holds an MBA and a career in commercial aviation and finance, and writes on logistics. and the costs of managing solar radiation and geoengineering. These two are well equipped to conduct this research.

What are we really talking about here?

Imagine a world where scientists have discovered that our programs are heating up the world and that people are too reluctant to change their emissions. Our methods of governance and our economic methods do not do the job. You do not really have to imagine it, that's where we are.

In this situation, scientists are forced to try to find technological solutions while hoping that politics and the economy end up doing things right. And that brings us to these two ideas: solar geoengineering and aerosol injection into the stratosphere (SAI).

When Mount Pinatubo erupted in the Philippines in 1991 and released 20 million tonnes of SO2 into the atmosphere. Global temperatures have dropped by 0.5 degrees Celsius over the next two years. Image Credit: By US Geological Survey Photo taken by Richard P. Hoblitt. - Archived source link, public domain, https://commons.wikimedia.org/w/index.php?curid=545018
When Mount Pinatubo erupted in the Philippines in 1991 and released 20 million tonnes of SO2 into the atmosphere. Global temperatures have dropped by 0.5 degrees Celsius over the next two years. Image Credit: By US Geological Survey Photo taken by Richard P. Hoblitt. – Archived source link, public domain, https://commons.wikimedia.org/w/index.php?curid=545018

Solar geoengineering is also called solar radiation management (SRM). The idea is to make the atmosphere reflect more solar radiation in space. MRS seeks to increase the albedo or reflectivity of the Earth.

Some SRM methods propose to protect and restore the naturally reflective surfaces of the Earth, such as sea ice, snow and glaciers. These would involve massive engineering projects and would be costly. There is no guarantee that they will work.

The new study published by Smith and Wagner focuses on another much-debated SRM: aerosol injection into the stratosphere (SAI).

The aerosol injection into the stratosphere focuses on the idea of ​​injecting sulphates into the atmosphere, in the stratosphere, about twenty kilometers in height. It is estimated that SAIs could counteract most climate change, be relatively inexpensive, enter into force quickly and have direct reversible climate effects. It sounds good, but there have been some disadvantages.

The first ideas of SAI proposed to use artillery, existing planes or balloons to inject sulphates or their precursors into the stratosphere. But each of these has its own problems. New research is focused on the development of new aircraft to deliver sulfates into the stratosphere.

Flying 20 kilometers higher up the stratosphere is not an easy thing to do. This is something we will not need to do only a few times to be able to use expensive rockets and reduce costs. A successful project would be a multi-year project involving a fleet of specialized aircraft stationed at several bases around the world.

In their study, Smith and Wagner analyze the costs and development times of a fleet of aircraft that could halve the increase in anthropogenic radiative forcing. The fleet would start small, swell with time and start operating in 15 years. They examined the existing aircraft and concluded that none of them were practical. The 15-year period gives ample time to develop the required device and have it tested and licensed.

The study looked at existing aircraft like NASA's Global Hawk. It can carry large payloads at high altitude for 24 hours. But the Global Hawk, like all other existing aircraft, is not able to meet the requirements of SAIL. Image Credit: NASA Photo / Tom MIller
The study examined existing aircraft such as NASA's Global Hawk. It can carry large payloads at high altitude for 24 hours. But the Global Hawk, like all other existing aircraft, is not able to meet the requirements of SAIL. Image Credit: NASA Photo / Tom MIller

"No existing aircraft requires the combination of altitude and payload capabilities required." – Wake Smith, co-author of the study.

A sustained flight at 20 km altitude requires specialized aircraft. The fuselage and the wings must be different from everything we have now, and the engines should be specialized. To conduct their study, they consulted with a number of aircraft manufacturers, engine manufacturers and other companies, including Airbus, Atlas Air, Boeing, Bombardier, GE Engines, Gulfstream, Lockheed Martin, NASA, Near Space Corporation, Northrup Grumman and Rolls Royce Engines. . .

They call their proposed aircraft SAIL: Stratospheric Aerosol Injection Lofter.

Both researchers clearly understand their motivations. They do not comment on the use of SAIL to combat climate change. They simply wanted to clarify the idea and see what a realistic SAI program might look like, as well as timing and effectiveness.

Dr. Gernot Wagner, one of the authors of the study, said: "Even though we make no judgment about the timing of the SAI, we show that one hypothetical deployment program starting in 15 years from now, both very uncertain and ambitious, would be technically 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 dollars a year over the first 15 years. "

Other studies have concluded that existing aircraft could be modified to combat climate change, but the two scientists discovered that this was not the case. In a press release, Wake Smith said, "The engineering issues relating to SAI and the many studies that were supposed to show that modified existing aircraft could do the job intrigued me. It turns out that this is not the case. It would require an entirely new aircraft design to perform an ISC under reasonable parameters, although quite hypothetical. No existing aircraft has the combination of altitude and required payload capacity. "

The NASA WB-57 is another high-altitude search aircraft that the study's authors deemed inappropriate for SAIL. Image: NASA / Johnson Space Center.
NASA's WB-57 is another high-altitude research aircraft that the study authors found unsuitable for SAIL. Image: NASA / Johnson Space Center.

This new SAIL aircraft should be able to carry a payload of 25 tons at 20 km altitude and be able to fly there. So what would this new plane look like?

The aircraft itself would need larger wings, the size twice as large as that of the current aircraft and a thrust twice as far. "We have developed SAIL's specifications with direct input from several companies in the aerospace and engine industries. Its weight is equivalent to that of a large passenger aircraft with narrow body. But to maintain a level flight at 20 km, it is necessary to roughly double the surface of the wing of an airliner of equivalent size and double its thrust, with four engines instead of two, Smith said.

According to the study, SAIL's fuselage would appear chunky and narrow, sized to accommodate a "heavy but dense mass of molten sulfur, rather than the large volume of space and air required for passenger comfort. SAIL would therefore have a wingspan much wider than the length. "

The engines would be modified versions of the existing engines, called "low-bypass". Although these engines exist, they are not used much because they do not consume a lot of energy. However, they outperform other engines at these extreme altitudes.

The two researchers are proposing to start with 8 aircraft operating approximately 4,000 flights per year and to increase by 4,000 per year as more aircraft go online. Fifteen years after the start of operations, the fleet would be close to 1,000 people. They would fly from several bases all over the world, at latitudes of 15 and 30 degrees north and south of the equator. The goal would be to inject about 0.1 Mt of S in the first year and then increase linearly by about 0.1 Mt per year thereafter.

Detailed chart of the SAIL flight activity. Image: Smith and Wagner, 2018.
Detailed table of SAIL's flight activity. Image: Smith and Wagner, 2018.

Smith and Wagner conclude that their SAIL program would not be so expensive. Their analysis shows that the program would cost about $ 2.25 billion a year over the first 15 years of deployment. This includes the design, testing and fabrication of a new aircraft type, modification of existing engines and operational costs. That's not much compared to the $ 240 billion that the US economy has lost over the last 10 years because of climate change.

In a press release, Dr. Wagner said: "Given the potential benefits of halving the predicted average increases in radiative forcing from a given date, these numbers point to the" incredible savings "of solar geoengineering. . Dozens of countries could fund such a program and the technology required is not particularly exotic. "

The ultimate goal of a SAIL program would be to save us time. That would not solve our problem of emissions. SAIL is only a temporary method of mitigation. It will not reduce CO2 emissions into the atmosphere and will not stop the other effects of climate change, such as ocean acidification. It only reflects part of the sunlight in the space.

This is where things get complicated. Assuming Wagner and Smith are right, should we use SAIL to fight climate change?

The idea of ​​a technological change in the climate raises some fears. Some organizations fear that the development of this type of technology would allow a rogue regime to do so in secret. The authors dispel this fear, saying that it would be impossible to conceal this level of flight activity involving partner countries around the world.

Smith said, "No comprehensive program of SAIs of the magnitude and nature discussed here could reasonably be expected to maintain secrecy. Even our first-year deployment program assumption involves 4000 flights at unusually high altitudes by aircraft of the size of an airliner in several flight corridors in both hemispheres. It is far too much aeronautical activity to remain undetected and, once detected, such a program could be deterred. "

Some climate change activists are suspicious of SAIs because they think it will create apathy for reducing emissions. They say that we would depend on it and that we would create an excuse not to reduce our GHG emissions. On Geoengineering Monitor, you can find these concerns explained and developed. They are concerned that large companies involved in fossil fuel extraction will fund geoengineering projects that would allow them to continue as usual.

The geoengineering monitor
The "HOME Manifesto" of the Geo-Engineering Monitor. It's a little too dramatic, but it's right. Image: Geoengineering Monitor.

In any case, the use of high-altitude aircraft to combat climate change is no more than an end of discussion. There is a body called the Convention on Biological Diversity (CBD). Under the CBD, 193 countries have signed a moratorium on geoengineering and agreed on the need to put in place a global mechanism to govern it.

But the SAIL program is a framework that should not be operational before 15 years. Is 15 years enough to develop a global mechanism for a geoengineering plan to combat climate change? We could hope for it.

We sink in a corner. The longer we wait before taking meaningful action on reducing emissions, the more draconian our actions will be. Our fears, founded and unfounded, will have to be overcome if we want to use SAIL to combat the effects of climate change.

We found ourselves in this situation and we will have to get by.

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