The climes they are a-changin’

By 2050, Columbia Basin could see higher summer temperatures, warmer winters, receding glaciers, and more extreme weather events.

The average annual temperature in the Columbia Basin is expected to rise about 2.3 degrees Celsius by 2050, a study on climate change has found.

That temperature change could result in more frequent landslides, floods, droughts and wildfires, and an increase in diseases, pathogens, invasive species and pests.

Columbia Basin Trust released the study, From Dialogue To Action: Climate Change, Impacts and Adaptation in the Canadian Columbia Basin, on Monday, September 24. It uses research from the Pacific Climate Impacts Consortium in 2006 and 2011.

The study finds that by 2050, the Columbia Basin could expect: higher summer temperatures, warmer winters, a decline in low-elevation snowpack, and receding glaciers.

Also predicted are earlier and larger spring freshets, lower water levels in streams in summer, higher water levels in streams in winter, reduced soil moisture, more extreme weather events, and increased variability in weather.

There could be up to four times as many warm summer days and nights, and increases in the temperature of the average hottest day of the month by a range of 0.4 C to 4.7 C.

There is likely to be about six per cent less rain in summer by the 2050s, but about seven per cent more precipitation in winter. However, more could fall as rain than snow at low elevations, which would decrease snowpacks and negatively affect ski resorts. But warmer, longer summers would be good news for water recreation, hiking and mountain biking.

As our streams and lakes shift from being snow-fed to rain-fed or a mixture of both, it may mean an earlier spring melt and earlier peak flows, leading to lower late-summer flows.

What’s more, the increase of rain on snow in winter could mean more runoff, potentially triggering landslides and flooding.

Warmer summer temperatures and less summer rain, on the other hand, could lead to more frequent and more intense droughts. The same changes may contribute to an increase in diseases, as well as the length of time those diseases can be transmitted. The ranges of mosquitoes, ticks, rodents and fungi could also increase. The climate changes could allow invasive species and pests to prosper, while bringing a decline in wetlands and alpine tundra ecosystems.

We are likely to see more extreme rain or snow events. Storms that used to happen every five, 10 or 25 years could occur two to three times more often. When combined with an increase in runoff and higher winter peak flows, this drastic precipitation can result in a greater potential for flooding, and it could occur earlier in the year.

Freeze and thaw cycles could happen more often, placing increased stress on road surfaces, rail lines, buildings and pipes.

Increases in summer temperatures, more frequent very hot days, longer warm spells, less rain in summer and pest outbreaks may also increase wildfire frequency. By 2100, fires in B.C. have been projected to increase by between 21 per cent and 190 per cent.

On the positive side, climate change could extend the growing season by between 18 and 35 days compared to 1971 to 2000.

Unfortunately, food production and distribution would be challenged globally as food transportation systems and supplies are affected by extreme weather events. That means that households may need to capitalize on the basin’s agricultural advantages by growing their own produce.

There may be fewer days we need to heat our homes, from 6,100 days during 1961-1990, down to 5,500 days between 2041 to 2070.

Climate change is diminishing B.C. glaciers, with scientists measuring a 16 per cent loss of total glacial area in the basin between 1986 and 2000.

That may lead to a rise in water temperatures in our streams and lakes, which could disrupt aquatic species such as bull trout, and decrease water quality if bacteria and algae can flourish in warmer water.

You can read the study, From Dialogue to Action, in full at www.cbt.org/climatechange.