For years, discussions on climate change have focused primarily on carbon dioxide. As the most prevalent greenhouse gas, it lingers in the atmosphere for centuries, trapping heat. Recently, however, scientists have been highlighting the significant role played by other, shorter-lived pollutants such as methane and black carbon (or soot). While these gases don’t remain in the atmosphere as long as carbon dioxide, they nevertheless have a high global warming potential (GWP). In my most recent Annual Greenhouse Gas Progress Report, I discussed this as the “tyranny of the near term”; the concept that what we do – or don’t do – about a warming planet over the next few decades will ultimately determine our fate. The near-term challenge arises because the global warming potential of carbon dioxide is one (1), regardless of whether the time horizon is 20, 100 or 500 years. In comparison, the GWP of methane is 72 over a 20-year period, and the GWP of black carbon soot is a whopping 1,600 over the same time frame. In addition, soot is a particular problem in the northern hemisphere because when it lands on ice or snow it increases the absorption of sunlight and thus hastens the warming (and melting) process. While the residency time in the atmosphere for each of these pollutants is much shorter than for carbon dioxide (12 years for methane and only days or weeks for black carbon), the near-term release of these gases poses a much more significant threat than the equivalent release of carbon dioxide
With this preamble for context, I note with some optimism today’s announcement by Hillary Clinton, the United States Secretary of State, that the U.S., along with Canada and four other countries, has launched a program through the United Nations Environment Programme to reduce the release of methane and black carbon, as well as hydrofluorocarbons, worldwide. It has been estimated that these gases have an outsized impact on climate change; accounting for 30 to 40 per cent of global warming. While many of the initiatives will focus on activities that should be undertaken in the developing world, such as replacing traditional cooking stoves with more efficient models, there are several measures that can be taken here at home. As I pointed out in my report, increased attention could be given to reducing emissions from diesel engines, equipment and locomotives – the main sources of black carbon in the province. As well, one of the main sources of methane in the province is due to the decomposition of organic materials in landfills. While steps have been taken to capture these emissions, I raised several questions in my report about the efficacy of such measures and would reiterate that the best control method is to divert organic waste from landfills altogether. Given that the lens is now focused on these gases internationally, I would suggest it is time for the province to similarly sharpen its sights.