Canada draws link between June heat wave and climate change with new attribution analysis

For the first time, the Canadian government has conducted a rapid analysis of a period of extreme heat and determined its connection to human-caused climate change.

The analysis conducted by Environment and Climate Change Canada (ECCC) found that a heat wave in Ontario, Quebec and Atlantic Canada between June 17 and 20 was made two to 10 times more likely because of climate change.

«In all regions, the event was made much more likely by the human influence on the climate,» Greg Flato, senior research scientist with Environment and Climate Change Canada, said during a briefing for reporters.

The analysis noted abnormally high daytime temperatures, high humidity and warmer-than-normal nighttime lows. Bathurst and Saint John, N.B., in particular, set all-time records for the hottest temperature since data was first gathered in the 1870s.

ECCC's study is the start of a pilot project, where researchers will analyze weather data and climate model simulations to compare how these types of events have changed between today's climate and the cooler pre-industrial one.

«By carefully analyzing the difference between these simulated climates, we can calculate how much the likelihood of an observed event has been altered,» he said.

Flato said the ongoing heat wave in Western Canada will also be analyzed, as will others in the future. The department will expand this system to analyze other extreme weather events, he said. Another ECCC scientist said its rapid attribution system is based on peer-reviewed techniques.

'Not just a one-off study'

The findings add to a growing area of research known as rapid attribution, where scientists use models to quickly determine to what extent climate change is linked to an extreme weather event, such as