Everyone is talking about the diplomatic and environmental success of the Paris Agreement, and duly so. But another monumental agreement was made in Paris last week - the Compact of Mayors coalition. This coalition is the world’s largest cooperative effort by mayors and municipal governments to reduce carbon emissions, measure progress, and prepare for climate change impacts

Since 3.5 billion, more than half of humanity, live in cities and urban built up areas, climate action by city mayors can bring about massive carbon savings. The coalition can also bring about new innovations in smart urban planning, public transport, and green architecture.

Strategies and commitments by the world’s cities can bring about huge-scale planetary protection. Already 400 cities, of which 117 are in the USA, have signed up to the Compact. Rio de Janeiro (pictured) has become the first city to be fully compliant with the Compact of Mayors.

The monumental Paris Agreement between 196 countries is both critical and hugely encouraging to curb global temperatures. But national-level action will not be enough. City-centric governance to reduce greenhouse emissions is key. The 400 cities already signed up could together avoid 740 million tons of emissions annually - a major step forward in reducing global warming.