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In 2021, the earth reached a dark milestone. carbon According to the United Kingdom, carbon dioxide (CO2) in the atmosphere reached 150% of its value in the pre-industrial era. Japan Meteorological Agency.. To prevent the worst effects of climate change, the world needs to reduce its net carbon dioxide emissions to zero by 2050.
However, even if this goal is achieved, it will take time to see the impact of CO2 reductions on global temperature, so there will be no sudden brakes on temperature rise.Adverse effects of Global warming It will last for decades. But is there anything else we can do to lower the temperature faster?
A research group at Harvard University believes that fine-tuning the composition of the Earth may be able to temporarily reduce the temperature of the Earth. EarthHigher atmosphere. Researchers wanted to test the feasibility of some of the techniques and their theories this summer, called the Stratospheric Controlled Perturbation Experiments (SCoPEx). Work is on hold, but the team still hopes the experiment will move into the not too distant future.
The ultimate source of Earth’s heat is the Sun, which immerses the daytime side of the planet in a stream of constant infrared radiation. About 30% of this is reflected by the atmosphere into space, the rest warming the planet during the day and radiating into space at night.In the delicate balance that prevailed before the Industrial Revolution, the incoming heat was accurately offset by the amount lost in space, ensuring an average world. temperature It remained constant.
The problem today is that CO2 emissions upset this balance by absorbing some of the heat that should be radiated into space and trapping it in the atmosphere. The more carbon dioxide in the atmosphere, the higher the temperature. In the long run, humans need to reduce the amount of carbon dioxide in the atmosphere to prevent the worst effects of climate change. However, other processes can reduce the temperature of the earth in the short term.
For example, a volcanic eruption blows away a cloud of dust particles high up in the upper stratosphere of the atmosphere, forming a protective shield that prevents some of the heat of the Sun from reaching the surface of the Earth. 1991 eruption Mount Pinatubo In the Philippines, for example, the average temperature in the Northern Hemisphere fell by about 1 degree Fahrenheit (more than 0.5 degrees Celsius) in the next 15 months. The SCoPEx team wants to get pages from such eruptions by injecting particles into the upper atmosphere to lower the temperature.
The basic idea called Stratospheric Aerosol Injection (SAI) is simple. A high-flying aircraft or helium balloon distributes a batch of fine particles, called aerosols, into the stratosphere above 12.4 miles (20 km), which is much higher than a normally flying airplane. Aerosols remain floating in the air and are too small to be seen as clouds from the ground, but are opaque enough to reflect some of the sun’s energy into space.
In simulation, SAI looks like a viable concept. A2018 Intergovernmental Panel on Climate Change (IPCC) Report A fleet of high-flying aircraft has discovered that it can deposit enough aerosols to offset the current level of global warming. However, aerosols need to be replenished every few years, and this method does not address the underlying cause of climate change, but only one of the symptoms of climate change. Greenhouse effect.. At best, it is a temporary measure that counters rising temperatures while countries reduce carbon dioxide levels.
So far, SAI’s work has been theoretical and supplemented by a limited amount of real-world data from volcanic eruptions. SCoPEx wants to make real measurements under carefully controlled conditions to enable better calibration of computer models. “If we want to provide decision makers with useful information about whether this works, we need to support the model,” said Frank Keutsch, a senior researcher at Harvard University’s Department of Chemistry and Chemical Biology projects. I am. Told the Boston Globe..
Volcanoes mainly release sulfur-based compounds.However, these compounds not only cool the atmosphere, but also undermine the protection of the earth. ozone A layer that protects us from harmful UV rays. That’s why the SCoPEx team focuses on less harmful aerosols. calcium Researchers want carbonates—chalk dust, in other words—to produce the desired cooling effect without harming the ozone layer.
The team wants to deploy a large unmanned spacecraft helium A balloon similar to a standard balloon, except that a propeller is attached to allow the team on the ground to steer it in a controlled manner. With the support of the Swedish Space Corporation, scientists were planning to launch a balloon near Kiruna, Sweden.
In the first flight, tentatively planned for next year, the balloon did not release anything into the stratosphere. Instead, it climbs to an altitude of 12.4 miles, where the team tests the maneuvering system to ensure that all scientific equipment and communications work properly.
If the test run is successful, the second flight will carry out a controlled release of 2.2-4.4 pounds (1-2 kilograms) of calcium carbonate at the same altitude. As the balloon moves steadily in a straight line during release, the aerosol particles form a narrow plume about 0.6 miles (1 km) long. According to the SCoPEx website, the balloon passes through the plume and observes how the particles disperse over time and reflect sunlight.
SCoPEx test flights are valuable in understanding SAI, but it is important to have a project in mind. “The goal is not to change the climate or see if it can reflect sunlight,” said David Keith, one of the project scientists at Harvard University’s Professor of Applied Physics. .. Earlier told HowStuffWorks.. “The goal is to improve the model of how aerosols are formed in the stratosphere.”
Keith said it would take at least another decade of research before a large aerosol could be released.This release may include an injection of about 1.5 million tonnes [1.4 million metric tons] We enter the stratosphere every year, “he said. “Approximately 100 aircraft will need to continuously fly the payload up to about 12 miles. [20 km] Altitude. “
However, SAI is still very controversial.One concern is that humans first pumped the climate crisis. Greenhouse gas How can people be confident that sending aerosols into the atmosphere will make things better? Computer modeling suggests that SAI is safe, but it can still have unexpected side effects. It disturbs weather patterns, harms crops by reducing the amount of sunlight they receive, and can damage the ozone layer if sulfide aerosols are used.
Indeed, some scientists are wary of following the SAI route.
“It’s a pretty scary idea to actually try to control the entire climate,” said Cornell University Senior Researcher and Senior Lecturer in Mechanical and Aerospace Engineering and Professor of Computational and Mathematical Sciences at the California Institute of Technology. Douglas McMartin said.Technology talked Smithsonian magazine..And IPCC, 2018 Discussion What the Panel called Solar Correction (SRM), “combined uncertainties such as technical maturity, physical understanding, potential impacts, governance challenges, etc., enable the ability to implement SRM in the near future. I will constrain. “
Due to these concerns, the SCoPEx team made a virgin voyage of helium balloons “until we were able to carry out a more thorough social engagement process to address issues related to solar geoengineering research in Sweden.” Was postponed.
However, Keith argued that the real danger lies in some maverick organizations implementing SAI without the kind of scientific data that SCoPEX wants to obtain. The second major objection to SAI’s research is that governments and businesses that are already reluctant to reduce carbon dioxide emissions are caught up in SAI as evidence that such reductions are unnecessary.
Such a situation could negate the potential benefits of SAI. Even if the SCoPEx mission is successful and SAI is fully implemented, it only complements and cannot replace carbon dioxide reductions. “It’s like a painkiller,” said Lizzie Burns, managing director of the Harvard Solar Geoengineering Research Program. “If you need surgery and are taking painkillers, it doesn’t mean you don’t need surgery anymore.
Is it possible to stop the earth from getting hot?
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