What causes the two heavens of ice and fire in the north and south of the earth?
Behind the frequent occurrence of extreme weather events, it represents a trend characteristic of climate - the earth's continuous warming. In the final analysis, whether "an individual is frozen to death" or "an individual is heated to death", it is closely related to global warming. In addition, climate change will also change large-scale circulation patterns, air-sea interactions, land-air interactions, etc., thereby affecting the occurrence patterns of extreme weather and climate events in different regions.
At the beginning of 2018, pet dogs in the northern hemisphere were "frozen", while eggs could be "fried" on the roads in the southern hemisphere. The "bomb cyclone" caused temperatures to drop sharply and hit new lows in many places in the eastern United States, with temperatures in some areas falling to minus 38 degrees Celsius. However, Australia, located in the southern hemisphere, is suffering from scorching heat. The temperature in Sydney once soared to 47.3 degrees Celsius, the highest in the past 80 years. A super temperature difference of nearly 100 degrees Celsius has occurred in the northern and southern hemispheres.
Scientific research has confirmed that global warming caused by the increase in atmospheric greenhouse gas concentrations caused by human activities can change the frequency, intensity, spatial scope and duration of extreme weather events, and may cause unprecedented extreme events. The latest research results show that when the average state of the climate changes, the frequency of extreme weather events will significantly increase. If the mean temperature shifts toward the warmer direction, extremely cold weather will decrease and the frequency of extremely warm events will increase significantly, and vice versa. Of course.
Take the "El Niño" phenomenon in the equatorial Pacific as an example. Global climate warming will increase air-sea exchanges, and the oceans will also absorb increased greenhouse gases in the atmosphere, causing seawater to heat up. Triggered by "El Niño" Extreme events and disasters will increase accordingly, such as floods in southeastern South America and western North America, as well as droughts in India, Australia and other places.
At the same time, global warming has also caused the accelerated melting of Arctic sea ice. In the past 30 years, the minimum coverage area of summer sea ice has been reduced by half. The direct consequence is to change the atmospheric circulation in the Northern Hemisphere winter by affecting the Siberian High, which in turn leads to a significant increase in the frequency of extreme low temperature events in the mid-to-high latitudes of Eurasia.
In recent years, extreme weather and climate events related to global warming have become increasingly frequent, bringing many adverse impacts to the social economy, ecological environment, and human health. According to statistics from authoritative organizations, 22,000 natural disasters occurred around the world from 1980 to 2013, causing economic losses of approximately US$3.8 trillion. About 87% of natural disasters and more than 70% of economic losses are directly related to climate disasters or meteorological conditions such as droughts, floods, tropical cyclones, high-temperature heat waves, and low-temperature cold damage.
If humans are not committed to curbing the trend of climate change, by the end of the 21st century, the probability of high-temperature heat wave events in land areas will be 5-10 times higher than now; extreme low-temperature events will decrease on average globally. ; The frequency of extreme heavy precipitation events will increase in most areas of the world.
How to reduce the probability of extreme weather events, make the earth less "surly", and strengthen risk management at the same time. This is the common responsibility of managers and scientists.