Higher temperatures and more extreme weather are likely to lower Canada's real gross domestic product by 5.8 per cent in 2100, assuming countries around the world fully meet their climate commitments.

Changing precipitation patterns, along with higher temperatures, affect the economy through their impact on agricultural output, labor productivity, human health, coastal sea levels, energy use, property damage, and tourism, according to report released Tuesday by the Parliamentary Budget Officer in Ottawa.

“Some climate effects like longer growing seasons and warmer weather could increase Canada’s GDP while more frequent days over 30 degrees Celsius, droughts, and severe storms will have a negative economic impact,” the budget watchdog says in the report. 

The 5.8 per cent scenario assumes that climate pledges by governments around the world are met in full, and on time, limiting the global rise in temperatures to 1.8C compared to pre-industrial levels. The report is meant to be a “first step” in the watchdog’s analysis of the economic impact of climate change.

The planet is on track to warm 2.1C to 2.9C by the end of the century compared to pre-industrial times, according to the UN Nations Framework Convention on Climate Change. Countries, including Canada, that ratified to the 2015 Paris Agreement aim to keep that rise to 1.5C, although the UN said last month there is “no credible pathway” to that goal. 

If governments fail to meet their policy commitments, and instead maintain their current trajectories, Canada’s GDP would fall an addition three-quarters of a percentage point, or 6.6 per cent, the watchdog said.