Why is it so cold if global warming is a reality?

CLAIM

There is nothing called global warming, or the winters would not have gotten so cold. 

FACT

Global warming can cause winters to be colder and more severe.

WHAT THEY CLAIM

There have been multiple posts on social media claiming that global warming is not real as otherwise, the winters would not have gotten severe in so many parts of the world. Such posts mostly surface in regions whenever the local temperatures in these places go down because of the winter season.

WHAT WE FOUND

Global warming can cause winters to be colder and more severe. In a study published in 2021, it was found that warming in the Arctic causes a disruption in the stratospheric polar vortex. This disruption is associated with extreme cold weather in some parts of the northern and southern hemisphere. 

What is the polar vortex? How does it cause colder winters in some regions?

The polar vortex is a low-pressure area—a vast expanse of swirling cold air—that is parked in polar regions. During winter, the polar vortex at the North Pole expands, sending cold air southward. This happens fairly regularly and is often associated with outbreaks of cold temperatures in the United States.

A stable polar vortex is usually farther north and the cold air typically moves west to east, according to the National Oceanic and Atmospheric Administration, USA. But a disrupted polar vortex acts differently — it can move farther south and the air can flow in a more wavy pattern.

ImageSource: NOAA

During winter, the polar vortex at the North Pole expands, sending cold air southward. This happens fairly often and can be associated with outbreaks of cold temperatures in some parts of the world. 

Is all cold weather in the south a result of the polar vortex? 

The answer is No. Not all cold weather comes from the polar vortex. Although cold air from the polar vortex can be pushed south, it typically remains parked in polar regions. It takes pretty unusual conditions for the vortex to weaken or migrate far south. Other weather conditions can cause cold arctic weather to travel even south.

Other Phenomenon responsible for cold weather

Global warming can cause harsh winter weather in other ways too. Warmer temperatures mean a warmer atmosphere. According to a study by National Geographic, when the atmosphere is warmer, it holds more moisture which causes an increase in precipitation — hence more snowfall when temperatures are below freezing. This can cause blizzards to be more intense.

Indian Context

Also, as per a recent study by the Indian Meteorological Department (IMD), Normal to below-normal maximum temperatures are likely over many parts of Peninsular India. IMD found the ongoing La Nina phenomenon to be a reason for the same. In IMD’s recent report, it is mentioned that, “The latest forecasts from MMCFS and other global models suggest that La Niña conditions are likely to continue during the upcoming winter season. In addition to El Nino- Southern Oscillation (ENSO) conditions over the Pacific, other factors such as the Indian Ocean SSTs also influence the Indian climate.” 

ImageSource: IMD

The map by IMD shows the probability forecast for minimum temperature in December 2022. The blue color region represents the minimum temperature. Southern India is expecting a colder-than-normal winter this year. 

Thus, depending on where you are in the world, an extremely cold winter could actually be caused by global warming. While temperatures in the winter are still expected to become warmer overall, learning about other possibilities is important because it can help us understand all the ways climate change can affect us.

Why is this a concern?

Severe winter weather is not about the slightly cold temperature in some regions for a day or two. These extremely cold temperatures and harsh winter storms could have a number of negative impacts. 

Colder than normal weather results in health impacts. In cold weather, the body increases blood flow to the trunk (to keep vital organs warm), tightens the blood vessels, and reduces blood flow to your extremities. It also affects the crop season in myriad ways. Colder than normal temperatures in southern India could decrease plant enzyme activity. This also disrupts the nutrient intake of plants because plants secrete enzymes to digest surrounding materials for soil. As a result, colder temperatures can stunt plant growth and can also cause them to die.

(with inputs from Aayushi Sharma)