Wildfires, rainfalls, tropical cyclones, and droughts have all made unwelcome headlines in 2021. Areas of Canada and diverse regions around the world have fallen victim to these extreme weather events, causing the loss of lives and livelihoods. However, these were not isolated, one-off events but rather the consequences of a history of climate change that has been amplified by human activities.
Hurricanes are one example of an extreme weather event that has wreaked tremendous havoc on communities in 2021, especially in the tropics. Hurricanes, also referred to as tropical cyclones, contain a closed circulation system of rotating clouds where wind speeds surpass 74 miles per hour. These weather systems generally begin as low-risk weather disturbances such as tropical waves which generate areas of low pressure underneath them. Combined with warm water temperatures, low wind shear, and thunderstorm activity, a bona-fide hurricane may form as the system moves west towards the tropics, where warm ocean air is sucked into low pressure areas and generates precipitation.
Studies have reported a significant increase in the proportion of Category 4 and 5 storms—the strongest and most dangerous level of storms—which is attributable to anthropogenic, or human-caused, global warming. While the frequency with which hurricanes occur has not increased due to anthropogenic climate change, the intensity of hurricanes certainly has. Nevertheless, the release of greenhouse gases and the concomitant increase in temperature may play a significant role in the rise in “rapid intensifications”—a phenomenon describing an increase in wind speeds of 35 mph over a mere 24 hours. Rapid intensification has increased by 4.4 mph per decade, which is partly attributed to the natural Atlantic Multidecadal Oscillation (AMO) but, importantly, is also a reflection of the impacts of human-mediated global warming. That is, natural cycles such as the AMO fail to fully explain the increase in rapid intensifications.
Not only did 2021 witness the catastrophic consequences of hurricanes, but the year’s climate was also plagued by extreme wildfires and landslides. To maintain a low risk of wildfires, the temperature and soil moisture, as well the quantity of trees, shrubs, and other dry fuel must be kept in an optimal range. Human-induced changes in climate have disrupted this fine balance, causing both increases in temperature and decreases in soil moisture, contributing to fire seasons that are dragged on for dangerously long periods.
Decreases in soil moisture lead to an abundance of dry organic material, which serves as fuel for forest fires. These conditions are also conducive to the growth and spread of mountain pine beetles, which can weaken trees, exacerbating the increase in dry material already present. Models reveal a direct and quantitative link between temperature increase and the extent of wildfires—an increase of 1 degree Celsius per year would correlate to an increase in burned area by almost 600 percent in certain forest types.
Wildfires are not only destructive on their own but can also lead to other disastrous events down the line, including landslides. Hillsides left barren after wildfires and devoid of roots from trees which normally stabilize forest debris are now especially susceptible to “giant debris flows”—massive sweeps of soil and rock. Moreover, this period of sensitivity to debris flows lasts for one to three years after a wildfire.
Increases in average temperatures caused by anthropogenic climate change have led to more extreme wildfires, leading to spikes in the numbers of landslides, especially in mountainous areas. Landslides are particularly prone to occur after rainfall—a concerning observation, considering that anthropogenic climate change has also exacerbated extreme rainfall events.
This slew of catastrophic weather events has inflicted great human and financial costs on geographic areas interspersed across the globe. Canada has been no exception: when regions of British Columbia experienced rainfalls of unprecedented intensity in November, thousands of residents were forced to flee their homes and at least four casualties were recorded. The financial cost amounted to nearly $7.5 billion from infrastructure damage. Kamloops, on the other hand, experienced record temperatures of over 40 degrees Celsius in the summer of 2021, as well as ravaging wildfires that followed, causing a mass displacement of residents.
In other areas of the world, hurricanes and droughts have also inflicted substantial costs. In late August and early September, the Category 4 Hurricane Ida swept through multiple US states, leaving more than one million people without electricity in Louisiana. Hurricane Ida ultimately inflicted a total of 95 casualties and an estimated financial damage of $65 billion. In regions of East Africa, severe drought conditions have slashed the livelihood of crop producers and diminished water availability to areas already experiencing high levels of food insecurity. These trends were not new to 2021 as Kenya had experienced dry seasons for the past several years, and they are likely to persist and intensify in 2022 as carbon emissions will continue to rise alongside average global temperatures.
These extreme weather events in 2021 have left governments scrambling to deal with the human and financial damages already inflicted. However, more funding should also be allocated to preventative strategies and strengthening infrastructure in communities most vulnerable to these climate events. Contending with the reality that these extreme weather events are likely to occur again in 2022 and in future years, some government officials such as Kamloops Mayor Ken Christian are calling for efforts to build emergency centres to house residents when temperatures reach dangerously high levels.
Other preventative approaches that should be taken include the protection of coastal communities through the restoration of wetlands, as well as the building of protective dikes and the implementation of wildfire prevention measures.
Canada is among the top ten carbon emitters and has been playing no small part in exacerbating the warming of the climate. This changing climate, which is especially pronounced in the northernmost region of the country, is bound to affect the intensity and frequency of the natural disasters we now know to be catastrophic. Learning from these disasters, government officials should begin to adopt a proactive approach to avert extreme climate events before they occur, while also providing ample support for the recovery of individuals and communities already affected by these extreme weather events in 2021. With the release of a National Adaptation Strategy later this year, Canadians are banking on a robust climate plan to dampen the impacts of extreme weather events in 2022 and in the years to come.
