THE ISSUE
Climate change is characterized by rising global temperatures and increasing severity and variability of climatic events. Across Canada, we are experiencing the impacts of climate catastrophe more frequently and more severely. Global mean temperatures have risen 0.74 degrees Celsius in the past century and are projected to rise by 4.3 degrees Celsius by 2100.
Localized warming and cooling, shifts in seasonality, and sea level rise all pose emerging threats to biodiversity in Canada and across the globe. Climate change impacts may be among the leading causes of biodiversity loss in the near future.
Climate change can manifest as abnormally intense weather events, like the B.C. summer heat wave that killed billions of marine invertebrates. These changes can also take place over longer periods of time, like in the Canadian Arctic, which is warming four times faster than the global mean.
The Cause
For decades, science has shown that recent climatic changes are caused by humans.
The rise of colonialism and the subsequent Industrial Revolution created new technologies and demand that facilitated the rapid release of greenhouse gases like carbon dioxide, which are most commonly created and released through the combustion of fossil fuels. Fossil fuels are ancient reserves of carbon-based compounds. Through the burning of fossil fuels, including thermal coal, oil, and gas, we have collectively undone millions of years of photosynthesis performed by prehistoric plants.
Once released into the atmosphere, greenhouse gases like carbon dioxide, methane, nitrous oxides, and chlorofluorocarbons act like an insulating blanket, trapping excess heat within the earth-atmosphere system. Broadly, the insulation effect of human released gases are responsible for modern climate change. Human-induced climate change is already here. The extra heat and energy in the earth-atmosphere system is manifesting in a variety of ways across the globe. As a general rule, climate change will directly increase the global average temperature, increase sea levels, and increase both the severity and irregularity of weather events, including drought, wildfires, and hurricanes.
The Impact
In the face of climate threats, organisms may need to adjust their distribution, behavior, and timing of activities to better meet their survival needs. Canadian species are experiencing especially intense changes, with studies showing they must adapt to a changing climate more quickly than the global average.
For example, many bird communities have shifted upslope in search of cooler temperatures. For birds, some insects, and certain marine species, the task of moving toward a more suitable temperature may be easier when compared to other organisms that may be unable to move quickly enough to seek suitable temperatures.
In the Canadian Arctic, female caribou are giving birth earlier to better align with an earlier spring. Golden eagles mirror this trend by arriving to their northern breeding grounds slightly earlier each year. Both of these iconic northern species are changing the timing of certain life events to coincide with times when food is plentiful. In other climates, unusual and intense weather events are increasing and associated with decreased nesting success of North American bird species.
In the face of rapid ocean change, the critically endangered North Atlantic right whale has adjusted both its primary source of summer prey and foraging habitat. Many whales once spent the summer months in the Bay of Fundy, feeding on temperate zooplankton species. Ever since 2015, most whales now feed on different species of zooplankton in the Gulf of St. Lawrence.
Despite the many ways species can adapt to climatic change, the greatest threat is that flora and fauna are unable to adapt or move quickly enough. At the poles and in alpine regions, species may not have cooler temperatures to migrate to, leading to local extirpations and even species extinctions.
Solutions
Climate action is urgently needed across all levels of society. Generally, climate-related actions can be categorized as solutions or mitigation and adaptation. Ultimately the dramatic reduction of greenhouse gas emissions and an international transition to a net-zero emission society is required. In Canada, the journey towards a net-zero country will require participation from all levels of society, government, and industry alongside an expressed recognition of Indigenous rights and the leading role of First Nations, Métis, and Inuit people in facing and addressing the climate crisis.
Beyond climate solutions, we must also rapidly implement climate mitigation and adaptation measures to improve the resiliency of human and ecological communities in the face of inevitable climate impacts. The best climate mitigation measures are those that minimize the risk of climate change impacts, promote biodiversity, and address other ecological and social issues. In other words, we need nature-based solutions.
For example, rather than using carbon-intensive concrete to build a sea wall, some North American communities have launched living shoreline initiatives to plant and restore native wetland and shoreline plant species whose roots help to stabilize the slope and prevent further erosion. As an added benefit, these plants help to sequester carbon, provide habitat for a diverse array of coastal organisms, remove pollutants, and restore coastal food sources for local communities. In the same way that biodiversity threats intersect, climate solutions often have intersectional positive impacts as well.
