GWP*: understanding the ins and outs of a new metric fit to methane

Methane is a powerful greenhouse gas which lifetime is short (circa 12 years). Taking into account this short life is necessary to better understand the relationship between emissions and temperature change. While the common understanding of climate change is based on CO2 equivalent model, this model is not fit for methane when it comes to temperature change caused by a certain level of emissions.

In order to better represent this physical fact, a recent metric developed between 2018 and 2021 called GWP* has been proposed by UK climate scientists. It is meant to easily calculate the temperature change caused by a regime of emissions over medium term (stable, increasing, decreasing), otherwise only accessible through complex climate models.

While GWP* genuinely brings new light on our understanding of the impact of methane emissions on warming, its use must be carefully calibrated. Its domain of meaning and use must be clearly understood and defined against the current reference metric being GWP100. 

With Xavier Poux, AScA

Chair/moderator : Benoît Rouillé, Idele