In a new study, scientists claim that tornado outbreaks have now doubled since the 1960s. While researchers still cannot link this environmental phenomena to climate change, they cannot also rule out any possibility.

This means that the number of tornadoes have not increased in the United States in the last 50 years, but tornadoes now happen in more outbreaks as clusters. 

Scientists from Columbia University in New York have identified two major factors that are crucial to tornado creation. The first one is how air rises when there is warm, moist air near the surface of the planet. The second one is called wind shear or when winds begin to blow from different directions from different altitudes.

The team suggests that increasing temperatures may also allow more air to rise. However, this would not affect wind shear increase. In this new study, researchers were able to identify wind shear as the main factor for the increasing number of tornadoes in larger clusters.

 

According to author of the study, , "We are still not saying that this is not caused by climate change but this suggests how we do not understand a lot about climate change, which might cause these large tornado clusters or if this event is not driven by climate change," Michael Tippet from the Columbia Initiative on Extreme Weather and Climate, who is the author of the study, said.

According to severe storm researcher, Bogdan Antonescu from the University of Manchester, large tornado clusters are yet to be determined as climate change-driven or caused by natural variability. Researchers say that more studies are needed to better understand thunderstorms and climate change.

In the past 10 years, about 110 people have died due to tornadoes. However, in the first half of 2016 alone, there was an estimated US $8.5 billion in damages due to tornadoes and thunderstorms alone, according to NOAA (National Oceanic and Atmospheric Administration).

This new study was published in the journal Science.