Models for optimizing public policy



The relationship between the economy and the environment is sometimes so complex that it makes it difficult to develop public policy. Charles Séguin, an economics researcher at Université du Québec à Montréal, has developed theoretical economic models to analyze this type of interaction and has applied them, on the one hand, to climate change and, on the other hand, to the management of Québec lakes. 

His models highlighted the impact of coordinating the work of the stakeholders responsible for managing the lakes.

In the case of climate change, Charles Séguin's model makes it possible to estimate deadlines for action. The researcher's results indicate that the greenhouse gas (GHG) concentration threshold at which climate impacts become irreversible is between 500 and 600 particles per million (PPM) of CO2. Since we are currently at about 400 PPM, this model suggests that it is still worthwhile to intensify our efforts to reduce GHG emissions.

In the case of Québec lakes, Charles Séguin used data collected by the ministry of the environment since the early 2000s and characteristics of watersheds, lakes and lakeside municipalities to better understand the dynamics of cyanobacteria (blue-green algae) proliferation in certain water bodies. His models showed a greater vulnerability in lakes with a depth of under 10 metres. In particular, they highlighted the impact of coordinating the work of the stakeholders responsible for managing the lakes, including watershed authorities and lakeside municipalities. Once a lake is surrounded by more than one municipality, the risk of experiencing episodes of blue-green algae increases. It appears harder to control the effects of farming and recreational activities when responsibility is shared between several actors. These results could have concrete benefits for the development of public policy.