The catastrophic weather events taking place across the globe – from Brazil’s and Australia’s flooding, Mississippi flooding, Springfield tornadoes – in one forecasters mind have two likely explanations.

Tony Barnston, forecaster at Columbia University’s International Research Institute for Climate and Society, says two phenomena – La Niña and the North Atlantic Oscillation – are likely responsible for the wildly varying patterns we’re seeing.

But what about climate change or "global warming"?

"Climate change? No,” said Howard Bluestein, professor of meteorology at University of Oklahoma. "This is something that happens every 10 or 20 years when everything comes together like this. This is just natural variability.”

The number of recorded tornadoes has risen dramatically, that’s primarily due to better reporting, tracking and more people, homes and infrastructures in the twisters’ paths, say researchers.