The Science of Climate Change

What’s the problem?

  • Climate change is a long-term shift in climatic conditions measured by changes in temperature, precipitation, wind, snow cover, and other indicators. It can involve both changes in average conditions and changes in variability. In particular, human activities that involve burning fossil fuels (eg. coal, oil and gas) change the composition of the atmosphere through emissions of greenhouse gases and other substances (primarily carbon dioxide). The build-up of greenhouse gases in the atmosphere from human sources is the primary cause of climate change now and into the immediate future.

  • According to NASA, the planet's average surface temperature has risen roughly 0.9°C since the late 19th century. Most of the warming occurred in the past 35 years, with the five warmest years on record taking place since 2010. This is not a blip. This is a trend with serious consequences, including:

    • Increased frequency and intensity of extreme weather events.

    • Shrinking ice sheets and declining arctic sea ice.

    • Decreased snow cover and glacial retreat.

    • Ocean acidification, warming oceans, and sea level rise.

  • What do these changes mean for Canadians? To name a few: declining fish stocks; more regular and higher intensity fires; increased smog and heat waves resulting in more temperature-related illness and death; the spread of infectious diseases such as malaria‚ dengue and yellow fever into Canada as insects carrying these diseases migrate northward with the warming climate.

  • The United Nations Intergovernmental Panel on Climate Change (IPCC) is the world’s foremost institution for climate change modelling. The IPCC reports with high confidence that the world will face severe climate impacts even with just 1.5°C degrees of warming (above pre-industrial levels) and even worse impacts should warming increase to 2°C. The global average annual temperature has already increased to 0.9°C above pre-industrial levels and is on track to exhaust the carbon budget associated with a 1.5°C increase by 2030.

What is the cause?

  • Increased carbon dioxide (CO2) and other emissions in the atmosphere. According to the International Energy Agency, coal is responsible for over 30% of the increase in global average annual surface temperatures above pre-industrial levels.

  • According to the International Energy Agency’s 2019 World Energy Outlook report, “in the last 20 years, Asia has accounted for 90% of all coal-fired capacity built worldwide.” This is a trend that we need to reverse through the advancement of cleaner energy sources.

Additional Resources