Extreme climates: A step forward from climate change

Extreme climates refer to regions or areas that experience severe weather conditions, abrupt climatic changes, or environmental characteristics that deviate suddenly and significantly from the norm. These climates are typically characterized by intense heat, extreme cold, heavy precipitation, strong winds, or other severe weather events. Extreme climates are not necessarily a direct result of steady climate change, but they can be influenced by long-term climate patterns and changes. Climate change refers to the long-term alteration of temperature, precipitation, wind patterns, and other aspects of the Earth's climate system. While climate change can lead to an increase in the frequency or intensity of certain extreme weather events, such as heatwaves, droughts, storms, or heavy rainfall, extreme climates can also occur naturally in specific regions due to geographical factors, atmospheric circulation patterns, or other local conditions. Extreme climates are not exclusively caused by steady climate change but can be influenced by it. They can occur naturally in specific regions due to a combination of geographical factors, atmospheric conditions, and climate patterns. Climate change, however, can exacerbate certain extreme weather events and potentially lead to more frequent or severe occurrences in some areas. Here we will discuss some important aspects and issues faced by researchers working in extreme climates.

​ ​ ​A tree under stress conditions due to water logging after extreme high ​ ​ ​ ​ ​ ​ ​    precipitation in Florida, US
A comprehensive classification and characterization of extreme environmental events (EEEs) have been performed by NOAA (National Oceanic and Atmospheric Administration). According to the NOAA classification system, EEEs are classified into six distinct categories, (i) extreme high temperature, (ii) extreme low temperature, (iii) extreme high precipitation, (iv) extreme low precipitation, (v) wind, and (vi) drought. As a researcher in the relevant field, I know several of my colleagues are having trouble fully understanding extreme low precipitation and drought. Most people think they are the two names of a single phenomenon. But, it's not in reality. The problem lies in its close relatedness in most of the geographic areas situated globally. Mostly, rain brings water and eliminates drought and its impacts on life. However, studying the impact of drought on crops and living organisms assumes the drought is a duration of the period of NO RAIN. Suppose an area faces >600 mm of rain in less than 48 hours and has no rain for the next six months. It will be the area affected by two EEEs (facing Extreme Precipitation and Drought as well). A somewhat similar situation has happened in Beihai city of Guangxi region, China. 
"The city of Yulin in the Guangxi region experienced 35 hours of non-stop rain on 8-9 June, while the nearby city of Beihai was flooded after 614.7mm of rainfall over 24 hours in the same period. This is approximately a third of the city's average yearly precipitation, and a June record for the Guangxi region. It is in stark contrast to May, when Guangxi experienced its lowest rainfall in 60 years." 
https://www.theguardian.com/environment/2023/jun/16/weather-tracker-extreme-rainfall-heat-china-asian-heatwave

​ ​ ​Plants facing abrupt temperature drop in Wuhan, Central China.
Another problem arises about the arithmetic calculation of the climatic thresholds beyond which the climate can be classified as an 'Extreme Climate'. Of course, the threshold levels of EEEs will be different in each region according to its normal environmental conditions. For example, certain regions near the Earth's poles, such as the Arctic or Antarctica, experience extreme cold climates due to their high latitudes and polar ice caps. These extreme cold climates have existed for thousands of years and are not solely a consequence of recent climate change. Similarly, areas prone to hurricanes or typhoons in tropical regions have a naturally higher risk of extreme weather events. To classify weather as an EEE, it should be much above (below) normal or extreme conditions as those falling in the upper (lower) tenth percentile of the local, period of record (Climate Extreme Index (CEI) by NOAA). Therefore, for each class of climate, the researchers should focus on the highest tenth percentile and the lowest tenth percentile of the values to decide the threshold level of EEEs. 

Dr. Aqeel Ahmad,
Chinese Academy of Sciences, Beijing, China