On Sunday, Arnold Schwarzenegger and Jerry Brown (former and current Californian governors), Al Gore and Michael Bloomberg (former NYC mayor and financier-philanthropist) said much of the United States remained behind the Paris Agreement, despite the current president Donald Trump’s efforts.

A staggering 7494 cities declared their commitment to tackling climate change as part of the Global Covenant of Mayors, announcing a new greenhouse gas emissions inventory standard for cities.

Mayors from 25 pioneering cities, representing 150 million citizens, promised to develop more ambitious climate action plans before the end of 2020 with an ultimate aim of becoming net zero emission and climate resilient cities by 2050.

Their staged plans will be about increasing their built environments’ resilience to extreme weather events while bringing wider social, environmental and economic benefits for their citizens.

The cities are all part of the C40 network: Austin, Accra, Barcelona, Boston, Buenos Aires, Cape Town, Caracas, Copenhagen, Durban, London, Los Angeles, Melbourne, Mexico City, Milan, New York City, Oslo, Paris, Philadelphia, Portland, Quito, Rio de Janeiro, Salvador, Santiago, Stockholm and Vancouver.

C40 Cities also announced support of nine African megacities in making a similar journey. These are: Accra, Cape Town, Addis Ababa, Dar es Salaam, Durban, Johannesburg, Lagos, Nairobi and Tshwane.

Paris mayor and C40 chair Anne Hidalgo said: “Mayors of the world’s great cities are shaping the century ahead and paving the way for a better, healthier and greener future. Mayors do what they must do, not what they can, and these plans and policies are an excellent example of our state of mind.”

This approach by cities has been widely echoed so far. One of the toughest problems the world has to solve in its energy transition is that of greening industrial cities. This is being tackled partly by The Urban Transitions Alliance, a network managed by ICLEI – Local Governments for Sustainability and funded by Stiftung Mercator.

The alliance presents an opportunity for industrial and former industrial cities to become crucibles for clean energy, innovation and sustainability. Cities like Pittsburgh, the former “Steel City” of the US; and Essen, Germany, a major coal mining region, have already been struggling with this process and created new visions for their future and, ultimately, for more sustainable economies.

ICLEI secretary general Gino Van Begin told the gathering: “Local and regional governments are making commitments that will help national governments close the gap between current national commitments and the emissions reduction.”

UN-Habitat executive director Dr Joan Clos agreed, adding that “the urban landscape is changing and with it, the pressing need for a cohesive and realistic approach to urbanisation”, which he said involved making cities and human settlements inclusive, safe, resilient and sustainable in line with the 2030 Agenda’s Sustainable Development Goal 11.

Net zero building work

Terri Wills, chief executive of the World Green Building Council, made the case that “net zero carbon buildings will be essential in helping countries achieve their nationally determined contributions”.

Seven new initiatives were announced to facilitate this, including work to design, implement and align climate action strategies across all levels of governments, by ICLEI and the global NDC Partnership.

Financial help is coming from the Cities Climate Finance Leadership Alliance, which acts as a matchmaker between financial support and infrastructure projects by local governments. It has published a new report detailing 170 initiatives from 50 international referent organisations in the field of financing. It shows that these efforts have more than doubled since 2016 in supporting readiness, project preparation and channelling funding and financing for subnational and urban infrastructure projects.

Amongst their projects is one to address barriers to change, including lack of funding, lack of capacity, inadequate legal frameworks, and the lack of understanding of subnational needs.

“Public, institutional and private investors must help us create new markets of opportunity for their sustainable investments. We need new financial models to test and deploy at scale,” mayor of Treichville, Cote d’Ivoire François Albert Amichia said.

The Global Alliance for Buildings and Construction (launched at COP21), which hopes to increase the decarbonisation of buildings and the construction sector, signed at COP23 a common statement to dramatically speed- and scale-up collaborative action.

Monica Fein, mayor of Rosario, Argentina, and vice-president of United Cities and Local Governments, welcomed “the celebration of a Human Settlements Day in the framework of the UN Climate Change negotiations, as a recognition of the critical role of all territorial actors”.

“It also reaffirms the inter linkages between the climate agenda and all global agendas, making cities and all human settlements inclusive, safe, resilient and sustainable,” she said.

Planners join the fray

Of all government agencies at national and local levels that can help facilitate speedy change, planning is one of the most crucial. A new global initiative, Planners for Climate Action, has been created, of global, regional and national associations of planning professionals and planning educators, to ensure their expertise is incorporated into discussions and action.

At the same gathering on Sunday, local and regional leaders from around the world signed the Bonn-Fiji Commitment of Local and Regional Leaders. It contains 10 pledges to deliver the Paris Agreement at all levels of government and another 10 demands of governments to recognise in the Nationally Determined Contributions, the contributions of cities, detailing a host of ongoing inspiring activities.

Stefano Bonaccini, president of the Council of European Municipalities and Regions (CEMR) and president of the Italian region of Emilia-Romagna, used this to call upon the EU to reflect these efforts in a more ambitious climate plan of its own.

“We want to see a new strategy to decarbonise Europe by 2050 that places cooperation between towns, cities and regions at its centre,” he said.

With more than 54 per cent of the world’s population living in cities, a proportion expected to rise to 75 per cent by 2100, it is more important than ever that cities’ voices are heard at a global level, and that they work together to share and solve common problems.

David Thorpe is the author of  Energy Management in Building, The One Planet Life and Sustainable Home Refurbishment.