The devastation that Hurricane Harvey caused the city of Houston was still in the news when Hurricane Irma struck several Caribbean islands before grazing Tampa, Florida, and Hurricane Maria rocked Puerto Rico. Out of the glare of the international media, extreme rainfall in eastern India caused even greater damage, killing more than 1,000 people. And these were only the latest of many flooding disasters in recent years, such as those in Wuhan, China, in 2016, and in Chennai, India, and Columbia, South Carolina, in 2015.
Global warming did not birth these storms. Climate change does, however, act as a "threat multiplier," as U.S. defense policy has described it. The most recent report from the Intergovernmental Panel on Climate Change (IPCC) asserts that, going forward, climate change will make bigger storm surges, rising sea levels, heavy precipitation events and extreme heat waves "very likely" and will make more intense hurricanes "likely." More recent research indicates an even tighter link with hurricane intensity. Based on these reports, it is highly likely that climate change will lead to spiraling fatalities and economic damage, along with multiplying public health dangers due to natural disasters, vector-borne diseases and the effects of heat on the human body. The costs will be greatest in developing countries.
Geography is a key determinant of a city's vulnerability to climate change. According to World Bank, of the top 10 coastal cities with the greatest risk of flooding damage (in absolute economic terms), five are in the United States, two in China, two in Japan and one in India. Measured as a percentage of gross domestic product, however, cities in developing countries, including Guangzhou, China, Ho Chi Minh City, Vietnam, and Mumbai, India, dominate the list.
Nearly all the world's nations signed a landmark climate agreement in Paris in 2015, pledging to contain planetary temperature rise within 2 degrees Celsius. But in June, U.S. President Donald Trump dealt global climate action a major setback when he announced that the United States intended to withdraw from the accord. Trump's announcement, regardless of whether it is eventually implemented, not only has heightened the role of other countries in climate action, but it also has highlighted the role of actors other than national governments.
Along with federal states and corporations, cities are a crucial part of this group. Though cities occupy only 2.7 percent of the world's land area, they contain about half of its population, generate 85 percent of its GDP and emit 70 percent of its greenhouse gases. These numbers are growing as the developing world urbanizes; by 2030, 60 percent of the world's population will live in cities.
The role that local governments can play in climate action was first raised in 1987 in the landmark Brundtland Report on sustainable development, named for Gro Brundtland, the former Norwegian prime minister and World Health Organization director-general. The report dedicated a full chapter to how cities can be involved in sustainability initiatives. The U.N. Framework Convention on Climate Change (UNFCCC) charter and the Kyoto Protocol, on the other hand, made no mention of local jurisdictions. As late as 2007, the IPCC Fourth Assessment Report made only a limited reference to the role of cities in combating climate change. Cities made a strong pitch for influence at UNFCCC's 13th Conference of the Parties meeting in Bali in 2007. But it wasn't until the 16th Conference of the Parties meeting in Cancun in 2010 that the UNFCCC finally acknowledged cities, referring to them as "governmental stakeholders." This nod opened the door for a deeper integration between the international and local planes of climate action.
Many cities across the world, however, didn't wait for intergovernmental conversations to include them. Several transnational city coalitions on climate change emerged in the 1990s, starting with Energy Cities, representing more than 1,000 European jurisdictions, and the Climate Alliance, a coalition of European cities and indigenous communities in the Amazon rainforest, both formed in 1990. The ICLEI-Local Governments for Sustainability followed in 1991, comprising more than 1,500 cities, and in 2005 the city of London initiated the C40 Cities Climate Leadership Group, which represents 90 mega-cities across the world. These more than two decades of efforts culminated with the Compact of Mayors initiative in 2014, which was backed by ICLEI, the C40 group, former New York City Mayor Michael Bloomberg and U.N.-Habitat (the U.N. agency for urban issues). Many of these city-driven initiatives started by focusing on reducing greenhouse gas emissions, but now they are also readying cities to absorb the effects of climate change.
Advantages Alongside Limitations
Cities face a fundamental structural limitation when it comes to global action. They are not sovereign entities in the international system, and, with few exceptions such as Singapore or Vatican City, they exist within sovereign nation-states. Cities, particularly in developing countries, also vary hugely in their geographies, resources and political power, which can make global coordination a challenge. Countries such as Brazil, Mexico and Sweden have substantially decentralized urban jurisdictions; others, such as China, feature considerable fiscal decentralization that exists alongside political centralization; in yet others such as India, Pakistan and Nigeria, cities are essentially at the mercy of higher levels of government on both counts.
But alongside these drawbacks come some advantages. City governments are closest to the individual citizen and can transform individual responses to issues in ways national governments cannot. In a time when cynicism toward national-level politics is high across many countries, this proximity matters. As concentrated nodes of private sector activity, cities also provide compact and manageable terrains for public-private partnerships, which are critical to address climate change.
Many cities have autonomy over certain functions of governance, such as the regulation of buildings and construction, urban transportation and solid waste management. And city governments, working with the private sector, drive spatial planning for future growth. These qualities of cities are important, because buildings and transport sectors in particular are major contributors to global emissions. It has been estimated that cities across the world, acting on their own, have sufficient power and jurisdiction to achieve 15 percent of the total reductions required to get the planet to within the 2-degree Celsius warming limit prescribed by the Paris Agreement.
Cities first began by setting targets and mandates to achieve mitigation progress with the Urban CO2 Reduction Project, which was launched by ICLEI in 1991. It set numerical targets of 10-20 percent reduction in CO2 emissions for the cities that participated. However, the next incarnation of the project, Cities for Climate Protection, abandoned numerical targets when it became clear they discouraged participation.
Thus, early on in the climate arena, cities innovated "soft" tools of transnational governance in preference to the traditional approach of targets and mandates. Well before the Paris Agreement, a network of cities pioneered policy innovations by jump-starting actions in carbon inventory reporting, sharing best practices, building capacity and self-regulating, with a strong inclination toward partnering with the private sector. In a sense, cities showed the way forward to achieve convergence on an extremely challenging area of governance, which was later taken up by intergovernmental organizations such as the UNFCCC.
The Power of Numbers
A number of examples of concrete progress in the mitigation arena have so far been demonstrated. There are now two platforms for reporting carbon inventories: the Carbonn Climate Registry (CCR) by ICLEI for cities and the Non-State Actor Zone for Climate Action by UNFCCC for unaffiliated groups. CCR currently includes more than 500 local jurisdictions covering 2.28 gigatonnes of greenhouse gas emissions.
Network governance has also led to innovative approaches to scaling up clean transportation through demand aggregation, which promises to reduce costs for climate action. For example, this year a group of cities in the C40 network jointly committed to ordering 40,000 clean buses. Around the same time, 30 U.S. cities jointly requested plans from auto manufacturers for supplying a total of 114,000 electric vehicles. There is scope for much greater demand aggregation of this sort, which, apart from aiding climate mitigation, can also reduce procurement costs for city governments and aid the generation of economies of scale for the private sector.
And there are further opportunities for action in other areas. Cities around the world are already focusing on sharing best practices on building codes, greener transit (such as bus rapid transit, pioneered by Curitiba in Brazil, and community cycling, innovated in several European cities) and sustainable waste disposal. Going beyond these, cities can be encouraged to set up their own distributed renewable energy generation plants, in which citizens hold equity. Germany has already pioneered this model.
Then there is scope for cities to participate in carbon markets. Though carbon markets have had a spotty record thus far, and are not easy to design, there is already an example of a successful transnational carbon market involving the subnational jurisdictions of California and Quebec, with Ontario as its latest entrant. Mega-cities are certainly able to push to set up their own such markets, in clusters of roughly similar levels of development. Though issues of "leakage" — in which businesses are tempted to migrate to cities without a carbon market— could be a serious barrier, carbon trading could also spur green innovations and therefore offer new sources of demand and supply within these jurisdictions.
Along with mitigation, adaptation is an important focus of city action. Arguably, cities can influence the latter even more than the former, as adaptation is by its nature a localized activity. Substantial power and resources for adaptation actions may originate at national and international levels, but implementation is almost entirely in the hands of city actors. Adaptation in cities implies working with government, market and civil society actors to strengthen infrastructure, reconfigure land use and enhance resilience to climate-driven or climate-magnified natural disasters. Efforts in these areas include attention to storm surge protection, expanded storm-water drainage, wetlands and green spaces, shelters and evacuation plans, and community health.
While the possibilities are many and exciting, the rhetoric on city coalitions acting on climate change sometimes has run ahead of actual outcomes. For instance, after U.S. President George W. Bush's rejection of Kyoto, more than 1,000 U.S. mayors signed a pledge committing themselves to a hard target of a 7 percent reduction of greenhouse gases from 1990 levels by 2012. Most cities failed to meet this pledge.
An open question is whether cities, despite their limited sovereignty as global actors, can forge meaningful transnational environmental or energy compacts in scale. Many nation-states, especially in the developing world, will resolutely prevent city jurisdictions from doing so. Furthermore, the source of funding for several city-led initiatives remains at the national or international level, acting as a limit to cities' autonomy in climate governance.
Yet the question of how cities can impact climate action is an intriguing one for the future, as conventional global governance increasingly fails to solve major collective action problems confronting the international system, from migration to the environment to slowing trade. In the medium-term, cities may benefit most by being complementary actors to national and international initiatives on climate change, even as they strategize to further strengthen transnational action.
Conventional geopolitical analyses focus on nation-states as the only relevant actors in the international system. And this approach is logical in many cases, especially those involving major threats to national security. However, the effect of subnational jurisdictions such as cities as geopolitical actors should not be underestimated. Cities can not only be rule-takers but also influencers — and even rule-makers, in certain arenas. Climate change and sustainability is unquestionably one of these areas.