“Because Fraser river salmon are so temperature dependent, global warming is a threat to their very existence.”

- Doug Chapman

Climate change is the change in weather patterns that a specific region encounters. Globally, the rate of temperature is regulated by the system known as the “greenhouse effect”, where gases such as methane and nitrous oxide absorb and emit radiation. All along this process, the radiation can pass through but the heat is not able to escape. The balance of this natural system has been disrupted by human activities. The more advanced and mechanized human lifestyle becomes, the more production of these gases and hence the increased warming trend all around the globe.

NASA, Fisheries and Oceans Canada, and other organizations’ climate models show warming in the past several years in British Columbia’s Fraser River, with a continued warming trend predicted for the future. This warming is caused by higher and higher carbon dioxide levels in our atmosphere, which is the result of the burning of fossil fuels and other anthropogenic factors, including deforestation.

According to Riverkeeper Doug Chapman: “At times,  Burrard Inlet already has depleted dissolved oxygen problems because of the huge volumes of improperly treated sewage being discharged daily by Metro Vancouver from its Lions Gate and Iona sewage treatment plants.”

• As the temperature increases, the solubility of oxygen in water reduces. This reduction in dissolved oxygen (DO) threatens fish, amphibians, and cocopods. Less DO causes increased metabolic rates, which can result in faster depletion of food sources and potentially more competition among more adaptive marine life, some of which may be invasive. Fish may become smaller, more susceptible to disease, and malnourished.
• Higher water temperatures also increase plant life, which can cause algae bloom, which further reduces oxygen in the water.
• The Fraser, currently predominantly a snow-melt river, could become a rain-dominated river, which would cause a change in elevation and flow, with a higher flow in the summer and fall. Any climate change like this will alter how fish reproduce, migrate, and survive.
• Water temperatures above 19-20° C are dangerous for salmon and other fish, degrading spawning rates, causing thermal shock, and becoming fatal at around 24° C. Changes in 1-2° C can produce significant cellular changes that are detrimental to cell walls, proteins, and enzyme metabolism.
• Global warming causes changing precipitation patterns, increasing evaporation, melting glaciers, and droughts and floods to become more frequent and intense

Any or all of these factors do and would affect the Fraser River and surrounding wetlands. Any unbalance as such would threaten fish and other wildlife on the Fraser. Already, many rivers in the world have been altered by global warming.