Même si nos forêts constituent des puits de carbone, nous devons réduire nos émissions industrielles de GES et l’utilisation des combustibles fossiles pour respecter l’Accord de Paris.
Those who oppose bringing in carbon taxes or other emissions-reducing climate policies in Canada frequently argue that there is no need to do so, because Canada’s forests and soil are carbon sinks that already store huge amounts of carbon dioxide (CO2). For example, during the 2017 Conservative Party leadership race, candidate Kevin O’Leary said in an interview, “We have 1.2 billion acres of forest land, we absorb four times more carbon than we emit. We are so lucky that we have this environment that does an incredible job of absorbing so much carbon we do not need to tax ourselves this way.”
Similarly, former Saskatchewan and Manitoba public servant Larry Martin wrote in a 2016 editorial that, based on Canada’s land mass and carbon absorption capacity, “Canada could already be absorbing 20 to 30 percent more CO2 than we emit.” Martin contended that Canada should argue for the inclusion of carbon offset accounting — a way of giving countries credit for natural or constructed carbon storage — under international climate change protocols, saying that Canada could gain as much as $10 billion a year by selling carbon credits to other nations.
But these optimistic scenarios of Canada’s carbon sequestration capacity do not withstand careful scrutiny. While Canada does have 347 million hectares of forest (just under 900 million acres), and while each hectare of mature forest can absorb about 6 tonnes of CO2 per year, unfortunately forests do not just store carbon — they also release it. Every year, millions of tonnes of CO2 is emitted as trees die and decompose, are disturbed by insects like the mountain pine beetle or are burned in forest fires. Fires in the boreal forest, for example, release about 170 tonnes of carbon dioxide per hectare burned. O’Leary’s numbers evidently don’t take carbon emissions from forests into account, while Martin’s numbers are based on a raw estimate of land mass, not a careful assessment of the relative contributions of forests, peatlands and farmlands.
Federal and provincial governments and independent scientists have carefully tracked and estimated carbon storage and emissions levels related to forestry and land use over the years, trying to determine if Canada’s forests, wetlands and farm soils are a net source or a sink of the world’s carbon. And in fact, natural and artificial carbon offsets are already part of our carbon reporting. Every year, Canada submits an estimate of carbon emissions and removals in the National Inventory Report to the United Nations Framework Convention on Climate Change (UNFCCC) — the international carbon reporting framework underlying the Kyoto and Paris agreements. The results have varied widely from year to year, depending on the level of forest fire or insect activity and forestry practices. Canada’s forests have fluctuated from being a net sink of 115 million tonnes of carbon in 1992 to a net source of 221 million tonnes of emissions in 2015, with a wide range of results in years in between.
Under the UNFCCC reporting conventions, countries have a number of options for reporting land use, land-use change and forestry (LULUCF) emissions. The system ensures that there is reasonable consistency in the way countries report their numbers and that countries are primarily held accountable for their human-caused emissions, not the vagaries of forest fires or insect infestations. Canada’s reported emissions, for instance, could spike wildly in a year with heavy forest fire activity.
Canada has naturally chosen the most favourable reporting options in its national reports. So far this has usually meant excluding LULUCF emissions altogether, since in most years they would have been a net source of emissions. But both the Harper and Trudeau governments signalled their intention to include LULUCF reporting to help meet Canada’s Paris Agreement targets. We are currently projected to fall 232 megatonnes short in 2030. By switching to one of the alternative accounting methodologies for emissions from land use, forestry and forest products allowed under the framework, Canada could narrow the gap — perhaps by as much as 63 or 126 megatonnes — even if our actual emissions don’t change. Canada is also involved in negotiating to allow for carbon credits from one country to be sold to another through what the Paris Agreement calls ITMOs (internationally transferred mitigation outcomes), along the lines Larry Martin was suggesting. But we must remember that any carbon reduction we sell internationally can no longer be counted as a reduction in Canada — it will count in the country that purchases it.
While changing our system of carbon accounting to include natural carbon sinks could bring Canada somewhat closer to meeting our Paris targets, it would be far from a magic bullet. When the effects of natural carbon emissions and events like forest fires are accounted for, Canada’s forests still do not sequester four times more carbon than Canada emits, nor does our land store 20 to 30 percent more carbon than we emit. Canada should certainly continue to pursue improved forestry and farming practices and preservation of our natural wetlands as means of increasing carbon storage, but we cannot claim that these carbon sinks eliminate the need to reduce our fossil fuel use and industrial emissions. To have any hope of meeting our Paris climate commitments, we will need to do both.
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