This past week, Environment and Climate Change Canada released Canada's Changing Climate Report 2019. The report is 444 pages long, tackling the issue of climate change from the basics all the way through to the implications for the various regions of Canada.
The headline news is both past and future warming in Canada is, on average, about double the magnitude than the global average. Further, northern Canada is warming at more than double the global rate.
This might sound a little confusing. After all, isn't Canada part of the globe? How can one region warm faster than another? The simple answer is it isn't just Canada. All of the extreme northern and southern latitudes are warming faster due to the convection within the atmosphere and the overall distribution of heat across the surface of the planet.
One way to think of this, albeit simplistically, is the tropics are already hot and are not going to get much hotter while the Arctic and Antarctic are cold and will warm up considerably. It is like boiling water - once it is at a boil, the temperature stays the same but if you drop an ice cube into the water, its temperature will rapidly increase.
Since 1948, Canada's average annual land temperature has increased by approximately 1.7 C. The territories have seen an increase of 2.3 C over the same period with the greatest relative warming happening during the winter months. Northern British Columbia is another region which has been disproportionately hit. When averaged out, our winter temperatures are significantly warmer than in the 1950s.
It is not just the land-based temperatures which are increasing. The oceans surrounding Canada have warmed significantly. On the Pacific coast, the ocean is both measurably more acidic as carbon dioxide dissolves into sea water and less oxygenated. The solubility of oxygen decreases with increasing water temperature and decreased oxygen means a lower capacity to sustain aquatic life.
The result is a net stress on the fish stocks on the west coast which when tied to our policies on fishing will likely lead to a permanent state of collapse over the next 20 years. The temperature of the northeast Pacific is projected to rise by roughly 2 C in winter and 3 C in the summer by 2065. And while wave heights off the coast have decreased over the past three decades, sea level rise could exceed 50 cm at Prince Rupert and Haida Gwaii.
Precipitation is projected to increase for most of Canada but not necessarily in the summer months. This might sound like a benefit but it will impact the growing season and lead to hotter, drier summers. The propensity for forest fires will likely increase and in northern B.C. we are likely to see summers similar to the past couple for the next two decades.
Ironically, the availability of freshwater will also change with an increased risk of water shortages during the summer months. Warmer winters will lead to earlier snowmelts resulting in higher winter streamflows and smaller ice packs. Further glacial ice loss will essentially deplete the "bank account" of stored water. The net result will be more flooding in the spring and lower flow rates during the summer.
While this will likely not have a significant impact on our ability to obtain freshwater in Prince George, other communities in the Lower Mainland and Vancouver Island will be increasingly in danger of water shortages requiring restrictions on use.
The temperature of the surface flow, particularly in the summer, will also impact the capacity of local streams, rivers, and lakes to sustain aquatic populations. Many of the species we think of as native to the north may not be able to withstand the changes in acidity, oxygenation, and temperature which will occur in local waterways as the overall flow of water through the system changes.
On top of all this, a warmer climate will lead to an increase in both the intensity and frequency of extreme weather events. Instead of getting a steady supply of precipitation, we will see more bursts leading to flooding. Periods of drought will exacerbate the overall effects as the dry landscape does not retain water. While there should be minimal impact in the north, the southern interior will see significantly more flash flooding.
The very first sentence in the executive summary for the report says "Canada's climate has warmed and will warm further in the future, driven by human influence." As a percentage of the world's global carbon dioxide emissions Canada is a very small player but global emissions will have a disproportionate effect on our climate. Perhaps this is only fair as we represent only 0.5 per cent of the world's population but produce a disproportionate two per centof the world's emissions.
The report is a wake-up call telling us what climate change will mean for all Canadians in the years and decades ahead.
