For thousands of years, the best way to protect your city from adversities was building a solid wall of stone around it. Raids and plunder by ill-disposed neighbors have fortunately become less frequent in most parts of the world, but the need for cities to act proactively to protect themselves has not decreased. While cities have always been exposed to the risk of extreme weather events, the negative impacts of climate change are likely to increase the burden on them.

coastal cities and climate changeFuente: Scouserdave at en.wikipedia. By Tim Radford

At last year’s UN Climate Change Conference in Durban, South Africa, the international community agreed to negotiate a global deal “with legal force” to address climate change and to start implementing it in 2020. While many observers were relieved that the negotiations got back on track, there is agreement that action already has to be taken now and that the years ahead must not become a “lost decade.” With some national governments still more focused on discussing what should be done rather than doing it, the stage is free for others to demonstrate what is possible. Champions are needed and cities are in a good position to take the lead where others are hesitant.

Why cities?

First and foremost, action is probably more urgently needed in cities than in most other places.

According to the World Bank, 79% of the population in Latinamerica and the Caribbean lives in urban areas. With their high population density and often exposed location, these are particularly vulnerable to climate impacts like heat waves, food scarcity and flooding and their detrimental effects on economic and social development. Cities have a genuine interest in addressing climate change in order to protect their citizens and to improve their quality of life. Table 1 gives an impression of the large share of urban areas that are located in low-lying coastal zones and could thus be threatened by sea-level rise, one of the risks likely to increase due to climate change.

Table 1: Cities are concentrated in coastal zones

(Share of urban settlements whose footprints intersect the Low Elevation Coastal Zone by population size, 2000)

Source: McGranahan, G. D. Balk and B. Anderson. 2007: The rising tide: assessing the risks of climate change and human settlements in low-elevation coastal zones. Environment and Urbanization, Volume 19, pp. 17-37.


Another good reason for cities to take action is their leverage in stabilizing the earth’s atmosphere.

Globally, they account for approximately 80% of all greenhouse gas emissions. This figure is likely to increase further due to rapid urbanization. The emission intensity of cities varies enormously as can be seen in the last two columns of Table 2, indicating much potential for improvement. While São Paulo, for example, produces only 116 ktCO2e for each billion US dollars of GDP that it generates, the figure is more than twice as large for Santiago de Chile. As cities are expected to grow substantially in the years to come, decisions made in this decade will largely affect their future carbon footprint. Sustainable city planning will be key for avoiding locking the world into carbon-intensive infrastructure for many years to come.


Table 2: Population, GDP, and GHG Emissions for selected large cities and urban areas in the world (sorted by emissions per capita)

Source: World Bank 2010: Cities and Climate Change. An Urgent Agenda.


Cities have some decisive advantages compared to national governments when it comes to taking action on climate change.

Decision-makers are on site and can offer solutions tailor-made for local conditions. Short distances facilitate stakeholder consultation and participation during planning and implementation which can contribute to the quality and acceptability of the outcome. Local action leaves room for innovation and diversity of approaches. Different cities may face different problems, but their large number and in many cases shared characteristics at least on a sector level makes learning through partnerships with peers highly beneficial.

If cities act on climate change, their impact will reach beyond their boundaries. Taking the matter into their own hands, they will act locally but push globally. Some cities have heard the call and are no longer waiting for their national governments to become active. They want to serve as beacons to show others the way. Notwithstanding limited resources, they have started to green their assets and build their defenses, making use of the support provided by platforms like the Emerging and Sustainable Cities Initiative. They have recognized that to overcome the greatest challenges they face today they need to cooperate, not build walls.

Read more about Cities and Climate Change in our blog