Over the past 800,000 years, the levels of CO2 in the atmosphere had never exceeded 300 parts per million (ppm); yet, we now find our atmospheric CO2 hovering just under 415 ppm and steadily rising (1). As CO2 is a greenhouse gas (GHG), it is not surprising that rising temperatures have been quick to follow. Data from the Goddard Institute for Space Studies at the National Aeronautics and Space Administration (NASA) clearly demonstrates that the earth is getting steadily warmer (2).
In addition, a National Oceanic and Atmospheric Administration (NOAA) report from February 2019 shows that of the 10 hottest years in recorded history, 8 have occurred in the past decade; and the top four hottest years recorded so far are 2015, 2017, 2019, and 2015, respectively (3). Global warming is not a problem for the future anymore. The trend of climbing temperatures will prompt a worldwide increase in sea levels and the frequency of intense storms, longer drought periods, and deadlier heat waves (4). In 2018, the Intergovernmental Panel on Climate Change (IPCC) reported that warming above 1.5 degrees C is likely in almost all emissions scenarios (5).
Although GHG emissions play an important role, the global rise in temperature is caused by multiple factors. This includes the ejection of particulate matter, such as soot from smokestacks, and increasing evaporation of water from the ocean into the atmosphere (6,7). Both of these effects work in a similarly to GHGs, absorbing energy from the sun and trapping it in the Earth’s atmosphere as heat (6,7). Water evaporation is particularly dangerous because of the huge natural store we have in the oceans. When the global temperature rises, water from the sea will evaporate into the atmosphere, where it acts as a GHG causing even more warming in the atmosphere, and therefore more evaporation (7). This is called a positive feedback loop, with each effect aggravating the other. Once set in motion, the impacts of this may become significant, worsening the effect of the GHGs released into the atmosphere through human activity (7).
It is important to note the climate crisis affects the entire planet differently. While the overall effect of higher GHGs on the climate is slight increases in temperature worldwide, is can affect our local areas in much more extreme ways (4). For example, we can look at the temperature changes from 1948 to 2016 in Canada. In this period, our country experienced warming of 1.7°C, about double the global rate; meanwhile, in Northern Canada, over the same period, temperatures rose by 2.3°C, around triple the global rate of warming (4). Five main factors influence the impacts of global warming on local climates: changing ocean currents, disruptions in wind patterns, distance from the sea, distance from the equator, and shape of the land (8). One example of changes brought on by climate change is precipitation patterns which influence the characteristics, duration, and severity of the seasons all over the globe (8). This is seen clearly in the Northwest Territories, where each season has experienced a warming trend over the past 20 years (9). The most dramatic effects are seen in the winters, where temperatures are on average 4.5°C higher than the pre-1948 average, with a 20-40% increase in precipitation (9).
We know that temperature averages around the world have already begun to increase. According to the IPCC, mean temperatures globally will continue to rise over the 21st century if GHG emissions continue unabated (5). The solution is clear – human emissions need to be stopped, or at least seriously reduced if we are to avoid the threat that the climate crisis poses to our Earth (5).
Observed changes in annual precipitation across Canada, 1948–2012, based on linear trends. Source: https://changingclimate.ca/CCCR2019/graphics/#pr_4621