Canadian Underwriter

Earth likely to see increase in frequency and intensity of storms, wildfires and flooding: AIR Worldwide

July 5, 2017   by Canadian Underwriter

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The earth is likely to see an increase in the frequency and intensity of weather phenomena, including severe thunderstorms, wildfires, inland floods and coastal flood, according to projections from catastrophe risk modelling firm AIR Worldwide.

The projections were contained in an AIR Worldwide report released last week titled Climate Change Impacts on Extreme Weather. The report examines climate change and its effects on atmospheric perils of relevance to catastrophe modelling and the insurance industry, AIR explained in a press release.

“Many in the insurance world are paying increased attention to climate change in light of reports of increasing variability of atmospheric perils such as windstorms and floods,” said Dr. Peter Sousounis, assistant vice president and director of meteorology at AIR Worldwide, in the release. “Meanwhile, regulators and rating agencies are beginning to ask companies to disclose how they are incorporating climate risk into their decision-making processes. As a result, clients have asked AIR to keep them apprised of the current state of the science regarding climate change impacts on extreme weather.”

The report was co-authored by Dr. Sousounis and Dr. Christopher Little from AIR sister company Atmospheric and Environmental Research. It is broken down into three sections: Section 1 summarizes key elements of climate and climate change and its relevance for weather extremes; Section 2 provides a synthesis of the latest scientific knowledge about how specific weather extremes may be affected by climate change, especially toward the end of the 21st century; and Section 3 identifies some of the complications and uncertainties surrounding the results and suggests a possible path forward for the developers and users of catastrophe models.

Among the report’s findings:

  • The overall number of tropical cyclones and extratropical cyclones is likely to decrease, but the frequency and intensity of the most “strong to extreme” storms (such as tropical cyclones that are Saffir Simpson Scale Categories 4 and 5) are expected to increase;
  • The impact of climate change is most evident for inland and coastal floods, both of which will overall see more frequent and more intense floods;
  • There is much greater uncertainty around how climate change will affect “strong to extreme” events (50- to 250-year return period) compared to the more common “weak-to-moderate events” (2- to 10-year return period) because existing historical data is insufficient and numerical climate models still do not simulate the most extreme events very well;
  • While relatively few studies project changes in wildfires due to climate change, one study found that “many areas in the Northern Hemisphere are expected to have increased risk of [wildfire]”: in particular, the western United States extending northward into Alaska, the northern portions of Canada, the northern part of Africa extending eastward into Saudi Arabia, and into central Asia and the northeast part of Russia; and
  • Significant regional differences may exist and the results assume a moderate-to-high emissions trajectory; the degree of uncertainty may vary as a function of a given emissions scenario.

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