A plan to stop global warming by spraying chemical substances to tens of thousands of meters above the ground

by PiccoloNamek

Since the industrial revolution that took place in the 18th century, human beings created energy from fossil fuels and developed civilizations with amazing speed. On the other hand, it is said that the emission of carbon dioxide and methane which bring about the greenhouse effect dramatically increased, causing global warming, but as one method to prevent global warming, " Stratospheric Aerosol Injection (SAI, stratospheric aerosol injection ) "Has been drawing attention. Meanwhile, researchers at Harvard University and Yale University have published the latest research papers on SAI.

Stratospheric aerosol injection tactics and costs in the first 15 years of deployment - IOPscience

We Could Spray Cheap Chemicals in the Air to Slow Climate Change. Should We?

When a volcanic eruption causes sulfur dioxide contained in the plume to be sprayed into the stratosphere, sulfur dioxide turns into sulfate aerosol in the stratosphere and reflects part of the light falling from the sun. This phenomenon occurred in the 1991 eruption of the Pinatubo Volcano in the Philippines and it was confirmed that the temperature of the earth has fallen due to reflection of sunlight.

SAI is trying to stop the influence of global warming by a method of "spraying chemical substances for reflecting the heat of the sun into the stratosphere" that mimics the global cooling effect of the volcanic eruption. In this way, techniques and techniques for artificially reflecting sunlight and manipulating the climate are called "solar engineering" or "geoengineering".

Sulfur dioxide is never expensive so it seems to be able to keep costs down relatively cheaply. According to the calculations of the research team, assuming that SAI's efforts will be started 15 years later, the total cost of preparation is about 3.5 billion dollars (about 400 billion yen), and the maintenance cost for 15 years thereafter averages 2.25 billion It is said that it will cost the dollar (about 250 billion yen).

In the national climate assessment announced on November 23, 2018, the GDP of the US decreased by 10% by 2100 due to the impact of climate change, and as of 2018 the economic loss is about 1.9 trillion dollars It is said to be 220 trillion yen). This is about twice the size of the Great Lease , which is a massive economic decline in the 2000s. It seems that the amount of hundreds of billions of yen is very high, but the cost of SAI is much cheaper than the astronomical loss caused by abandoning global warming.

However, the research team argues that it is difficult for existing aircraft designs to develop aircraft that can fly at such a high altitude that spraying sulfur dioxide can produce an effect. Wake Smith of Yale University, coauthor of the paper said, "Even if chemicals are sprayed at a height of 35,000 feet (about 11,000 meters) from the ground where the plane flies on a daily basis, the number It will rain on the sun and rain on the ground, but if sprayed in the stratosphere, chemicals will stay in the sky for about 12 months to 18 months. "

by Hughhunt

Also, Smith said, "If all the ice in Greenland melts into the ocean, we assume a scenario where the sea level rises rapidly and the coastlines around the world are overflowing, no matter how much the earth is cooled down, Ice that has melted by the formation will never come back to the land from the ocean and the ice of Greenland is the result of snow accumulated for millions of years. "Although it is meaningful to study geoengineering, it never means It should understand that it does not completely solve the impact of global warming.

in Science, Posted by log1i_yk