Media attention rains on UVic climatologist

There was something ironic about the deluge of media attention that followed the release last month of a new study linking an increase in the intensity of extreme precipitation events to human-induced global warming. At the centre of the media flurry was UVic climatologist Dr. Francis Zwiers, one of the paper’s co-authors, who suddenly became one of the most sought-after climate experts on the planet.

“We were completely overwhelmed by the storm of media interest that was generated by this paper,” says Zwiers. “It was fun, but exhausting.”

Over a 24-hour period Zwiers responded to more than 25 media inquiries, including The New York Times, Scientific American, National Geographic, USA Today, Washington Post, The Globe & Mail, CBC Quirks and Quarks and news agencies from Europe, Japan and Brazil.

Zwiers has since been asked to make a presentation on the study to a US Congress committee hearing in Washington.

The study, which was featured on the cover of the Feb. 17 edition of Nature, offers the strongest evidence to date that human-induced global warming may be responsible for the observed increase in the intensity of heavy rain and snow events in the northern hemisphere over the past several decades.

Zwiers, a former scientist with Environment Canada, participated in the research while with the government agency. The lead author of the study is Seung-Ki Min, an Environment Canada research scientist.

The study used a rigorous and scientifically accepted method of looking for the “fingerprints” of human-caused climate change.

Min, Zwiers and colleagues used observations from 6,000 weather stations across much of the northern hemisphere to study how intense precipitation changed between 1951 and 1999. They found a widespread trend toward more intense precipitation extremes.

They then used sophisticated computer climate models to determine whether those observed changes can be explained by natural climate variability. They could not. The rise in extreme precipitation events only made sense when the effects of increasing greenhouse gases were factored into the models.

“The most plausible explanation for this trend is the steady increase in global temperatures caused by greenhouse gas emissions,” says Zwiers, noting that warmer air can carry more water vapour, which enables more intense precipitation extremes.

In fact, the study team admits that the climate models they used may have underestimated the observed trend. “This implies that extreme precipitation events may strengthen more quickly in the future than projected and that they may have more severe impacts than estimated.”

Zwiers is president and CEO of the Pacific Climate Impacts Consortium (PCIC). An initiative of UVic, PCIC is a not-for-profit corporation that provides practical, science-based information for policy action in the areas of community planning, ecology, forestry, hydrology, transportation, agriculture, public health and energy.