Ottawa's weather to get warmer, wetter and wilder: study

Climate change will cause Ottawa's seasons to shift noticeably, with shorter winters, less snow and a heightenedrisk of extreme weather including tornadoes, new projections show.

The city and the National Capital Commission commissionedCBCL Limited to predict how the weather in the region will change, so they can start planning now to mitigate the effects.

According to the firm, there will be moreheat waves andflooding, putting pressure oneverything from emergency services to thefoundations of buildings. The changing climatewill also shorten the cross-country skiing season in Gatineau Park and theskating seasonon the Rideau Canal, according to the report.

• City, NCC preparing for wetter, warmer future
• Floods prompt city to think fast on climate change planning

Average temperatures in Ottawa are expected to rise by 1.8 C by the 2030s, by 3.2 C bythe 2050s, and by 5.3 C bythe 2080s, according to the419-page report.

At the same time, the capital region could become wetter, with more intense precipitation in winter and the "shoulder seasons," althoughless of it is likely to fall in the form ofsnow.

Winters could be four weeks shorter by the 2030s and eight weeks shorter by the 2080s, with far more freeze-thaw cycles between December and February, and fewer "deep freeze events."

• City playing catch-up as potholes multiply

Ottawa saw 11 very hot days per year from 1981 to 2010, when temperatures rose above 30 C, but there could be 25 to 28 such days by the next decade, and 36 to 72 of them by the 2080s.

The projections become less certain the further they are into the future.

The consultantconsidered scenarios in which greenhouse gas emissions were moderate or high, leading to global warming of 1.8 C or 3.7 C, according to standards established by the United Nations' Intergovernmental Panel on Climate Change.

While Gatineau, Que., was not a partner in the study, the report states the findings complement work that city is doing with Ouranos, a non-profit made up of government agencies and universities.