Storms in the Northern Hemisphere are getting worse, and human impact on climate change is to blame, says a University of Victoria researcher whose work made headlines around the world last week.
Francis Zwiers, director of UVic’s Pacific Climate Impacts Consortium, co-authored the first study linking global warming to extreme precipitation events across North America, Europe and Asian weather stations.
Published in the Feb. 17 edition of the journal Nature, Zwiers and lead-author Seung-Ki Min conclude that acts of nature — heavy rain and snow, floods and mudslides — are intensifying and are doing so at a rate faster than scientists were able to project.
“Climate scientists have made arguments that it’s caused — as the atmosphere warms, (and is) able to hold more water vapours — not necessarily more days of heavy precipitation, but the events are more extreme,” Zwiers said.
The worst annual storms were tracked from 1951 through 1999. The likelihood of a rainfall event being more extreme than the previous year’s highest precipitation increased slightly with each subsequent year.
“The average waiting time between major events is getting shorter,” added Zwiers, the former head of climate research at Environment Canada.
Zwiers, an expert in applying statistical methods to climate variability and change, said our understanding of climate change is limited by the speed and consistency of data.
In Greater Victoria, an extreme event might currently translate to 75-100 millimetres in precipitation at one time — numbers that suggest the need for more robust storm water handling infrastructure, from holding ponds to rain gardens, Zwiers said.
“One thing I think we can be sure of is that these events will be stronger over time,” he said.