The role of cities as key actors in addressing climate change and achieving sustainable development has become widely recognised over the past two decades. For example, the 2013 report of the UN High-Level Panel of Eminent Persons on the Post-2015 Development Agenda stated that “cities are where the battle for sustainable development will be won or lost” (UN High-Level Panel, 2013). The European Union’s (EU) Covenant of Mayors for Climate and Energy (CoM) is an example of how that battle is already being fought in the cities and municipalities of all sizes that will be a driving force behind the European Green Deal (EGD), the EU’s new roadmap for reaching climate neutrality by 2050.
The European Commission launched the EU Covenant of Mayors, as it was then called, in 2008 following the adoption of the 2020 climate and energy targets, which compelled member states to reduce greenhouse gas (GHG) emissions by 20% compared to 1990, to increase renewable energies by 20% and to improve energy efficiency by 20% by 2020 (EC, 2008). Although these targets were mandatory only for member states, the idea behind the creation of the CoM was to mobilise municipalities and build on their potential to reduce GHG emissions and support the delivery of the 2020 goals.