How the tonga volcano may continue to erupt will affect the global climate

Over the past few days, volcanoes in the South Pacific island nation of Tongahun Aha Apai have erupted violently and triggered tsunamis, posing a serious threat to the local area and the surrounding area.

On January 18, from the latest FY-4B volcanic ash cloud synthesis scheme provided by the National Satellite Meteorological Center of the China Meteorological Administration, it can be seen that most of the mineral particulate matter in the volcanic ash cloud hovers around the volcanic eruption point and gradually settles, while the light green cloud in the volcanic cloud is gradually separated and gradually spreads westward, which has now affected the Australian mainland.

According to expert analysis, this part of the light green cloud is mainly composed of acid gases (such as sulfur dioxide) in volcanic ash clouds.

The eruption is probably the largest in nearly 30 years. Based on statistical analysis of historical volcanic activity events, experts predict that eruptions could last for weeks or even years. For human beings, volcanic eruptions are undoubtedly a disaster, but at the same time, topics such as "volcanic eruptions will change the global climate" and even "benefiting from volcanic eruptions can offset the impact of global warming and reduce the pressure of emission reduction" have sparked heated discussions on the Internet. What are the facts, and what will be the impact on the mainland?

Volcanic eruptions do cause cooling

"A series of studies have shown that volcanic eruptions generally have a lasting impact on the global and East Asian climate for the next 1 to 2 years, with a cooling effect of about 0.3°C. For the continent, volcanic eruptions can weaken the intensity of the following year's East Asian summer winds, which in turn leads to the southward summer rain band of the continent. Zhu Congwen, deputy director and researcher of the Institute of Climate and Climate Change of the Chinese Academy of Meteorological Sciences, said.

According to the data, in 1783, the eruption of Naki Volcano in Iceland caused an unusually cold climate in Europe from 1783 to 1784; in 1815, the eruption of Mount Tambora in Indonesia caused a serious climatic disaster, the average global temperature dropped by about 0.4 °C to 0.7 °C the following year after the eruption, and many parts of the northern hemisphere suffered a "summerless year"; in 1991, the Philippines Pinatubo Volcano erupted, injecting a large amount of aerosol into the stratosphere, and the global average temperature dropped by about 0.5 °C a few months later... These famous volcanic eruptions have proved that volcanic eruptions are indeed associated with falling global temperatures.

Zhu Congwen introduced that the Tonga Island volcano is in a low-latitude region, and in the past 100 years, there have been three large-scale low-latitude volcanic eruptions, namely Agung Volcano (March 17, 1963), Elchijom Volcano (April 4, 1982) and Pinatobo Volcano (June 15, 1991). In the winter of the year after their eruption (December to February), temperatures were low in most parts of the mainland except the northeast and Xinjiang. In addition, the occurrence of La Niña also played a cooling role in the winter temperature of the mainland except the Qinghai-Tibet Plateau that year.

"The main reason why a volcanic eruption causes cooling is that it injects sulfur-containing aerosols into the atmosphere, which enter the stratosphere and help the Earth reflect more sunlight out, creating a cooling effect in the atmosphere." Zhu Congwen explained, but it should be noted that this must consider an important factor - "magnitude".

Monitoring maps from NASA's Aura (Breezy in Latin) Earth observation satellite show that the release of sulfur dioxide on the first day of a volcanic eruption on the island of Tonga was 62 kilotons. Michael Mann, distinguished professor of atmospheric sciences at Penn State University, analyzed that the eruption of Mount Pinatubo, which caused the global average temperature to drop by 0.5 °C, eventually released 20,000 kilotons of sulfur dioxide. Therefore, to achieve the effects of previous eruptions on temperature drops, the Tonga island volcanoes would need to emit more sulfur dioxide.

In this regard, Chao Qingchen, director of the National Climate Center of the China Meteorological Administration, pointed out that the above ideas are not reasonable. "The temperature drop caused by volcanic eruptions generally lasts only a few years, and a maximum of about ten years. But the global warming we're talking about today is a longer-scale concept of time. Nest Dust stressed.

Is it advisable for an "artificial volcanic eruption" to cool the earth?

"If volcanic eruptions have a cooling effect, then don't we just have to artificially create this aerosol and spread it into the atmospheric stratosphere, and then we don't have to spend a lot of effort to reduce emissions?" In response to this view on the Internet, Chen Ying, a researcher at the Institute of Ecological Civilization of the Chinese Academy of Social Sciences and the main author of the third working group of the fifth and sixth assessment reports of the IPCC, clearly opposed it.

"Without the premise of reducing emissions, SRM (solar radiation intervention, that is, changing the radiation balance of the Earth system on a large scale through artificial methods to cope with global warming) will certainly not solve the problem of climate change." Chen Ying said that SRM will not solve the problem of ocean acidification, and it may also bring other risks and uncertainties, such as changing the temperature and precipitation distribution.

Cao Long, professor of the Department of Atmospheric Sciences at the School of Earth Sciences of Zhejiang University and the lead author of the first working group of the sixth assessment report of the IPCC, introduced that the currently proposed SRM method mainly includes injecting aerosols into the stratosphere, low cloud lighting of the ocean, and increasing the albedo of the ocean and land surface. The basic starting point of these methods is to increase the albedo of the earth-gas system, reduce the solar radiation reaching the atmosphere and the ground, and counteract the warming effect caused by the increase in greenhouse gases through short-wave radiation intervention. The IPCC Sixth Assessment Report assesses the impact of SRM on the climate system and the carbon cycle, with key conclusions including that SRM can offset climate change from some of the increases in greenhouse gases at global and regional scales, but not completely offset climate change caused by increases in greenhouse gases at global and regional scales, and that SRM cannot mitigate ocean acidification.

"Therefore, further research is still needed, such as recognizing the cooling potential and impact of different SRM methods on the climate system, and vigorously strengthening research on the global and regional climate impacts of different SRM methods implemented at different locations and times." Cao Long said. (Reporter Fu Lili)

Source: Science and Technology Daily