In international news, 228 world cities are taking the lead on climate action through set greenhouse gas (GHG) reduction goals or targets.

Today’s modern cities are home to more than half of the world’s population and represent about 70% of global energy consumption and GHG emissions.

According to research organisation Worldwatch Institute, over 200 cities, which represent a combined population of 439 million people, could propel countries to meet their Intended Nationally Determined Contributions (INDCs).

The INDCs are the national GHG reduction pledges embodied in the COP21 Paris Agreement.

Groups steering the change

The emphasis placed on climate commitments and sustainability goals has seen the C40 Cities Climate Leadership Group expand to over 80 cities, including 10 African cities.

Whilst the Compact of Mayors, which includes 54 African city mayors, launched at the 2014 United Nations Climate Summit, is the largest coalition of city leaders addressing climate change. In addition, the ICLEI-Local Governments for Sustainability works with more than 1,000 cities around the world.

In Worldwatch’s report on “Can a City Be Sustainable?” contributing authors and co-directors Michael Renner and Tom Prugh state: “The challenge over the next several decades is an enormous one.

“This requires not change around the edges, but a fundamental restructuring of how cities operate, how much they consume in resources and how much waste they produce, what they look like, and how they are structured.”

In a company statement, Worldwatch cautions that if trends continue, urban populations are expected to increase to six billion by 2045, at which point two-thirds of all people will live in urban environments.

“If current trends in urbanisation continue unabated, urban energy use will more than triple, compared to 2005 levels, by 2050.”

Consider the variables

Cities vary widely in their per capita greenhouse gas emissions. Rotterdam in the Netherlands, for example, emitted 29.8 tons of carbon dioxide-equivalent per capita in 2005, whereas Paris emitted just 5.2 tons per capita.

[quote]Many variables, such as climate, urban form, and primary energy source, affect a city’s level of emissions. Economic factors, such as the wealth and income of residents and the level and structure of economic activity, also play a major role, states Worldwatch.

“Only demand-side policies that succeed in sharply reducing energy consumption in transport, buildings, waste handling, and agriculture can address the urgent need to decarbonise energy,” write Renner and Prugh.

“It is cities that must step up to the front lines of that battle.”

Policy directives needed to secure success

In a company statement, Worldwatch advises that in conjunction with policy changes, cities’ success will depend on having both comprehensive data and financial support.

Current protocols, such as the one developed by the World Resources Institute, C40 Cities, and the ICLEI, can be used to measure or estimate GHG emissions in cities worldwide. Financing sustainability in cities may be easier in some cities than in others.

Among the C40 cities, only three-quarters have budgetary control over property or municipal taxes. In poorer cities, multilateral development banks and a variety of donors may play an important role.