The amount of cold air above the Northern Hemisphere this winter is near a record low, providing yet another clear sign of the planet’s warming climate. An analysis of 76 years of temperature data from about a mile above the ground reveals this alarming trend. The depletion of cold air in the atmosphere has resulted in Arctic air blasts being less vigorous than in the past, while unusually mild weather events, like the one currently occurring over the central United States, are becoming more frequent and intense.
The evaluation of the cold-air supply in the Northern Hemisphere is based on temperature data obtained from about 5,000 feet high in the atmosphere. Professor Jonathan Martin from the University of Wisconsin has been studying the size of the cold pool at this level for around a decade. The size of the cold pool refers to the area of the hemisphere covered by temperatures at or below 23 degrees (-5 Celsius). This winter’s cold pool is set to conclude as the second-smallest on record.
A prominent trend in recent years is the decreasing size of winter cold pools. Nine out of the 10 smallest winter cold pools since 1948-1949 have occurred in the 2000s. This shrinking trend was first identified by Martin in a study published in the Journal of Climate in 2015.
According to Martin, the rate of warming in the climate has remained consistent over the past 20 years. The shrinking cold pool in the Northern Hemisphere during winter serves as unequivocal evidence that the globe is warming up.
This year, the shrinking supply of cold air in the atmosphere coincides with what is likely to be one of the warmest winters on record. Numerous locations in the United States are experiencing record-high temperatures, with deviations ranging from 30 degrees above normal. Cities like Dallas, Minneapolis, and Chicago have seen exceptionally warm temperatures, reaching new records for February.
Globally, more than 200 countries have observed record warmth this week, making January the eighth consecutive month where it registered as the warmest on record. Additionally, 2023 was declared Earth’s warmest year on record for both land and oceans.
Some skeptics argue that rising surface temperatures are influenced by urbanization, changes in sensor location, and other factors that may skew the data. While scientists acknowledge such influences and adjust surface data accordingly, upper-air data is considered even more reliable and difficult to refute. The measurements taken higher in the atmosphere are free from the potential contamination of urbanization, providing a robust and dependable signal.
The year-to-year fluctuations in the size of the cold pool appear to be unrelated to El Niño, a periodic warming of the ocean surface in the central and eastern Pacific. El Niño is known to contribute to extreme surface warmth in certain regions. Martin’s analysis of the cold pool does not indicate any significant correlation with El Niño.
Martin calculates the size of the Northern Hemisphere cold pool for each day of winter, comparing it to the average size for that day since 1948-1949. This method allows him to rank each winter season based on its average cold-pool size. Only the 2014-2015 winter experienced a smaller cold pool than the current one. However, this winter’s cold pool reached a record low size on four days, which Martin finds extraordinary.
It’s important to note that even when the cold pool contracts, it does not guarantee mild weather throughout the entire Northern Hemisphere. The regional nature of winter impressions often differs greatly from the overall perspective of the hemisphere.
The dominance of upper-air warm extremes aligns with the ongoing trend of heat records surpassing cold records. In the United States, nearly 8,000 warm-weather records have been set this winter, compared to around 2,300 for cold weather.
These findings emphasize the urgent need for action to address the warming climate. The potential future trends related to this issue are of paramount importance. As temperatures continue to rise, it is likely that extreme weather events and record-breaking warmth will become the norm.
In light of these predictions, industries and governments must prioritize sustainable practices and adopt clean energy sources. The devastation caused by climate change is evident, and proactive measures must be taken to mitigate its impacts.
Furthermore, individuals can contribute to combating climate change by making environmentally-conscious choices in their daily lives. Reducing carbon emissions, conserving energy, and supporting initiatives that promote sustainability can all make a significant difference.
The urgency of addressing climate change cannot be overstated. The consequences of inaction are dire, and it is our collective responsibility to safeguard the planet for future generations.