Quantifying Human Impact on Climate Change
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Climate change on our planet is attributable to human activity and associated greenhouse gas emissions (GHGs). Governments around the world, including Canada and Quebec, have committed to reducing their GHG emissions according to specific targets.
Various types of inventories are carried out each year to measure progress and identify areas of focus in order to reach these targets. However, the tools are imperfect, inaccurate, and do not take into account spatial and temporal resolution.
A Difficult and Inaccurate Measurement
To begin with, GHG emission inventories require a lot of time and resources to conduct and are therefore published a few years late. They follow a bottom-up approach based on theoretical calculations, different data sources, and numerous assumptions. In fact, emissions are approximated by multiplying activity data by emission factors for each source and then summed up per sector. For example, in land transport, fuel quantities sold during the year in a given territory are generally multiplied by GHG emissions from the combustion of one litre of fuel. The results are highly uncertain and do not take into account spatial and temporal resolution, making it impossible to identify factors that contribute most to emissions. For example, still in land transport, current inventory does not identify when and where travel takes place, the transport mode, etc. Better spatial and temporal resolution would make it possible to study the effect of different factors on emissions, such as the impact of weather conditions or the development of active corridors on transport practices. To measure the effectiveness of strategies outlined in climate change action plans and to determine which strategies have the greatest impact at the lowest costs, governments need better measurement tools that provide an up-to-date picture of changes over time and space. These tools should have the accuracy and spatial and temporal resolution needed to better target the different sources of emissions.
Researchers from the Canada Research Chair in Measuring the Impact of Human Activities on Climate Change propose the development of a high resolution spatial and temporal resolution inventory for the City of Montreal, using an improved approach. The proposed methods could be extended to other territories.
Accurate Inventory of GHGs in Space and Time
The proposed strategy to improve Montreal’s GHG inventory consists of three key issues:
Annie Levasseur, Professor at ÉTS and Canada Research Chair in Measuring Human Activity Impacts on Climate Change
- Developing better data and model combinations to improve inventory accuracy and resolution on a sector-by-sector basis.
- Integrating methane emissions, some of which are currently ignored even though they are far from negligible.
- Including a life cycle approach to incorporate GHG emissions occurring outside the study area, such as emissions related to fuels and materials production.
In addition to a more accurate GHG assessment, the resulting inventory will also take into account emissions produced outside the assessed territory, to avoid solutions that ultimately displace emissions from one area to another rather than actually reducing them.
Methods to Evaluate Mitigation Strategies
The Chair also plans to create advanced modelling tools to evaluate climate change mitigation strategies at the provincial and national levels. These tools will be obtained through the development and combination of different models making it possible to take into account phenomena that are often overlooked due to their complexity—market effects that may lead to carbon leakage into other sectors or territories—or other factors influenced by human activity, such as the albedo variations caused by land use changes.
Research results will help support stakeholders at different government levels in developing and measuring the effectiveness of optimal climate change mitigation strategies.
