The Arctic is accelerating warming
The Arctic is in crisis. The Arctic at the top of the earth heats up faster than any other place on the earth, and the melting speed and area of ice and snow have been setting new records. The Arctic summer sea ice is melting intensified. This is a very serious problem, because these climate changes that occur in the Arctic not only stay in the Arctic, but also affect other regions of the planet.
In addition, the Greenland ice sheet is also melting. And if all the Greenland ice sheets disappear, then this alone can raise the global sea level by 6 meters. Frozen Arctic soil and permafrost are also continuing to melt, releasing more carbon dioxide and methane into the air. In 2019, huge wildfires in the peatlands of Siberia continued to burn for more than a month. At the same time, the warming of the Arctic has also severely affected the weather system in the northern hemisphere. From an economic point of view, by the end of the 21st century, if the Arctic warming is not effectively curbed, then the economic impact will be huge, the latest estimate is 67 trillion US dollars.
If all the Greenland ice sheets disappear, then this alone could raise the global sea level by 6 meters.
Some people say that we are living in an era of “climate emergency”. “Climate Emergency” is the word of the year published in the Oxford Dictionary in 2019, and its usage has increased 100 times in 2019. The Oxford Dictionary defines it as: urgent action is needed to reduce or stop climate change and avoid irreversible environmental damage caused by climate change.
So, how should we deal with this severe situation? Some scientists put forward the slogan “Let us freeze the Arctic again.” Some scientists believe that the melting ice in the Arctic can be “recovered” by “interfering” in the Arctic climate system. This is an imaginative idea.
Although it is neither cheap nor simple to implement, scientists still believe that because the Arctic region is facing too serious a crisis, at least we should study some ways to “recover” the Arctic ice.
Today, climate intervention in the Arctic seems more necessary than previously recognized, because the Arctic region is accelerating warming. The results of simulations by scientists building mathematical models and satellite images show that we may see an ice-free summer in any year in the future.
When the dark ocean is directly exposed to the sun, it will not reflect sunlight like bright white sea ice, but will absorb more solar heat. In the past 30 years, the resulting temperature rise is equivalent to a quarter of the total carbon dioxide released by human activities during the same period. This increase in temperature has weakened the polar jet, leading to an increase in the “blocking” weather situation and corresponding extreme weather events such as droughts, floods and heat waves.
When the dark ocean is directly exposed to the sun, it will not reflect sunlight like bright white sea ice, but will absorb more solar heat.
Need for direct intervention
In the past 40 years, approximately 2.4 million square kilometers of Arctic sea ice has disappeared.
The crisis facing the world is huge. If the Arctic is allowed to continue to change in this way, it will pose a huge security risk to all parts of the world, and may lead to changes in the climate system beyond our ability to recover. Of course, if we started to act when scientists first suggested reducing global greenhouse gas emissions decades ago, then we could have prevented the Arctic from warming. It’s a pity that we didn’t take action at the time, and we haven’t.
Because of this, more and more scientists believe that if we want to save the Arctic, we need to directly intervene to “manipulate” the Arctic climate system. For this reason, scientists have proposed three main solutions: one is to increase the coverage of sea ice; the other is to increase the brightness of the ice surface to reflect more sunlight; the third is to brighten the clouds to reflect more sunlight and let the air in the Arctic Get cold. These three options all belong to the category of geoengineering (also called climate engineering, climate adjustment, or climate intervention), that is, the degree of intervention on the environment is large enough to offset climate change. Some scientists believe that since it is too difficult to do a good job of reducing emissions, then try to directly intervene in the climate system.
An important concern for scientists who advocate for intervention is that as the Arctic climate warms, microorganisms will decompose thawed organic matter, causing methane to begin to seep from the seafloor.
They worry that as the warming continues, a slight exudation of methane will develop into a methane explosion.
Therefore, we need to “recover” the ice in the Arctic seas to avoid catastrophic methane explosions. Not only that, in addition to the methane that is sealed on the seabed, it is estimated that 1 trillion tons of carbon are stored 3 meters below the surface of the Arctic soil. As long as a small part of this enters the atmosphere, it will offset our efforts to reduce emissions. The problem that nature poses before us seems to be: on the one hand, the methane released from the bottom of the sea will quickly warm the earth; on the other hand, as the permafrost layer on the land melts, it will also undergo complex chemical processes Let the earth warm.
But the climate intervention program also disturbed many scientists. They worry that people will reduce their emissions reduction efforts because of these programs.
The first plan
The first proposal came from Steve Gal, an astrophysicist at Arizona State University.
The plan he proposed is to build a wind-driven water pump to pump the seawater under the ice surface onto the cold ice surface in winter, making it easier to freeze the seawater, thereby thickening the sea ice on the sea surface and expanding the coverage. This method has recently been proposed to prevent the collapse of the Antarctic ice sheet.
As sea ice drifts around, Gale’s idea is to install wind pumps on the sea ice in the north of the Arctic. It is difficult to melt. He believes that this seems like an impossible task, because the North Pole is a very large area, but it is not impossible, but the scope of the project is huge.
According to Gale’s calculations, we need to build 10 million wind-driven water pumps throughout the Arctic to re-freeze them, which will cost about US$500 billion. This is a lot of money, but it is insignificant compared to the $67 trillion (the economic price we will pay for Arctic warming if we don’t take action). Scientists believe that this is feasible in physics and conforms to basic natural principles. But so far, there is only one wind pump model operating in the laboratory, which is far from the actual operation of the program.
The second program has made some successful progress outside the laboratory. The solution is to cover the ice with shiny white beads. These tiny beads increase the reflectivity of the nascent thin ice, thereby protecting the ice surface from sunlight. The advocate of the program is Stanford University engineer Raisley Field. His team is exploring how to “save” the
Arctic ice by using silica beads . These bright, non-toxic beads are similar to sand in chemical and physical properties, but are smaller and more powder-like, with a diameter of about 65 microns (0.065 mm).
Field’s team has conducted experiments in this area many times, the most notable of which was carried out on North Meadow Lake, which is about 4,200 square meters in Alaska. Experiments have shown that these microspheres increase the reflectivity by about 20% and slow the melting of ice. However, if these materials are used to cover an area of 25,000 square kilometers in the Arctic, the cost of materials alone will cost about 300 million US dollars, and the lowest summer sea ice cover since the Arctic sea ice has been recorded (appearing in 2012) is also 3.4 million square meters. Km, 25,000 square kilometers accounted for only 0.7% of it.
There are also many questions in this plan, especially whether it is effective for sea ice? After all, so far, experiments have only been conducted on frozen lakes. Moreover, when the ice melts, what happens to these beads? Some of them will settle and then fall into the mud at the bottom of the lake. What changes will happen as a result is unknown. Therefore, some scientists worry that adding millions of tons of silica to the Arctic will affect the Arctic ecosystem. This gave the plan a red light.
Some scientists doubt the feasibility of using the above two methods to change the surface of ice and whether these methods can be effective tools to deal with climate change, and whether the use of “white beads” will affect the large-scale climate. Feasibility is highly doubtful.
By using silica beads to “recover” the Arctic ice. These bright, non-toxic beads are similar to sand in chemical and physical properties, but smaller.
Experiments have shown that these beads increase the albedo by about 20% and slow down the melting of ice.
The third option
Some scientists believe that the most promising potential intervention is not to directly repair sea ice, but to indirectly increase sea ice by brightening the clouds over the Arctic. This idea can be traced back to the 1990s. At that time, John Latham of the University of Manchester in the United Kingdom began to think about how to suppress the greenhouse effect by reducing the sunlight reaching the surface of the earth. Latham is interested in a phenomenon called the “first indirect effect” (Twomey) of aerosols. This effect describes that the amount of solar radiation reflected by clouds back into space depends on the concentration of cloud droplets. In the lower atmosphere, water vapor condenses on aerosol particles (cloud condensation nuclei) suspended in the air to form cloud droplets. If the concentration of cloud condensation nuclei is increased, the concentration of cloud droplets will increase accordingly, thereby increasing the cloud’s reflectivity to solar radiation. Based on this, Latham believes that it is possible to increase the concentration of cloud droplets by spreading sea salt particles over the ocean, thereby reflecting more solar radiation back into space.
We can know from the satellite images of the ship’s track (equivalent to the wake left by an airplane) that the sulfate discharged by the ship can become cloud condensation nuclei and increase cloud cover. The Latham team built a computer model to show how to restore Arctic sea ice by brightening the ocean’s stratocumulus clouds. This large and round cloud is currently the most common type in the Arctic, and it usually appears in groups and covers a large area.
In theory, this method seems very promising, but actual testing is another matter. To implement this method, we first need a system that can spray ultra-fine sea fog into the lower atmosphere over the ocean on a large area. British scientist Stephen Salter has a very advanced plan for this. He proposed the idea of spraying ultra-fine sea fog into the lower atmosphere by remotely controlling an unmanned boat, and submitted it to the British Government Environmental Audit Committee Argument. But the lack of funds hindered the implementation of this idea.
Of all the ideas to prevent the “collapse” of the Arctic, the most feasible is to increase the reflectivity of the atmosphere to sunlight. But the current effective investment in reflecting sunlight is minimal. This exposes us to huge short-term climate risks, and there are not enough quick response options to control the temperature rise within a safe range.
The Arctic region is continuing to change from white to blue. Vadam, who has led 40 expeditions to the Arctic, has witnessed the great changes in the Arctic. He said: “When I first went to the North Pole, you could imagine the entire northern hemisphere as a solid continent. The ice used to connect Eurasia and North America, but now part of the ice has become a blue ocean. . Physically speaking, the world has become’broken’.”
If the concentration of cloud condensation nuclei is increased, the concentration of cloud droplets will increase accordingly, thereby increasing the cloud’s reflectivity to solar radiation.
It is possible to increase the concentration of cloud droplets by spreading sea salt particles over the ocean, thereby reflecting more solar radiation back into space.
The role of the cloud
Clouds play a vital role in controlling climate. The reflection of sunlight by clouds, especially in tropical areas, plays a very important role in cooling the earth. But we don’t know how cloud formation will change as the earth gets hotter. This means that we do not know how much the earth will warm when the concentration of carbon dioxide in the atmosphere rises to a certain value.
Climate change deniers believe that there are too many uncertainties when using climate models to predict climate warming. One reason is that the sensitivity of climate models is uncertain. How much does the temperature increase when the carbon dioxide in the atmosphere doubles? In the prediction results of the climate model, the temperature increase range is 2-5℃.
We don’t know whether the climate is very sensitive. If it is sensitive, then when the concentration of carbon dioxide in the atmosphere doubles, the earth’s heat will increase accordingly. The evidence obtained by climate scientists from the latest improved climate models shows that our planet is more sensitive than we thought. If the concentration of carbon dioxide in the atmosphere increases by only about 70 ppm, the temperature will increase by 1°C. Then, at the current rate of carbon dioxide emissions, it only takes 20 years to increase the magnitude of global warming from 1.5°C to 2°C compared to the pre-industrial level. This is the so-called “severe impact” level, which means that there will be global warming. More extreme weather—forest fires, floods, and tropical storms will increase in number and intensity.
The formation of clouds requires aerosol particles in the atmosphere, and many of these aerosol particles are pollutants formed from industrial processes and the burning of fossil fuels. Since these particles cool the earth directly or indirectly through their effect on cloud formation, gradually eliminating their sources will uncover the truth that the previously hidden greenhouse gases are warming the climate. Therefore, in order to understand how much additional warming we can expect as the atmosphere becomes cleaner, we need to figure out how clouds affect climate sensitivity. Some scientists believe that experiments to brighten ocean clouds may reveal one of the most difficult and important questions in climatology: how do aerosols affect clouds? Before we try to intervene in the climate system, we need to understand it as much as possible.