Cities & the climate crisis – part of the problem, and the solution

23rd April 2015

This blog post is part of a three-part series to be published over the COP20 event. Other posts will focus on sustainable energy and climate finance.

As climate change professionals and government representatives gather in Peru’s capital Lima for the UNFCCC Conference of Parties (C0P20), Jennifer Lenhart of Wageninen University discusses why cities are an apt platform from which to tackle climate change, provides examples of urban climate actions, and gives recommendations on how to address some of the challenges and opportunities of urban climate governance.

An urban era in a time of climate change

Cities are home to half of the global population and estimates suggest this will rise to 60 per cent by 2030 – mostly in rapidly industrializing countries (UN, 2014). This has consequences for climate change. Cities produce around 50-70 per cent of global greenhouse gas (GHG) emissions from things like energy in buildings, urban infrastructure and transport (IEA, 2014; UN-Habitat, 2011). Equally, cities are vulnerable to the consequences of climate change. Key Findings from the IPCC 5th assessment report, including storm surges and sea level rise, especially since three-quarters of large cities are coastal. Due to building networks, paved surfaces and the consequent soil sealing, cities are disproportionately affected by rising temperatures (the ‘urban heat island’ effect) and intensive storms, which can lead to urban flooding.

Cities respond to the climate crisis

Cities represent a place for climate action and for urban actors (such as local governments, NGOs, architects and developers, energy and transport companies) to respond to the challenge. Often in collaboration, they adopt measures to address mitigation and adaptation – or combine these with efforts to address vulnerability or sustainable development.

Renewable Energy and Energy Efficiency

mamlo water heaters

Credit: City of Malmö, Sweden
Urban solar water heater in Malmö

Local governments can adopt energy efficiency (EE) measures in municipal buildings and invest in renewable energy (RE), including subsidies for installation on residential buildings, such as in Rizhao, China. They work with energy companies and architects to retrofit industrial areas into eco-neighborhoods, such as in Malmö, Sweden’s Western Harbour, which focuses on EE, RE and green space planning.

Urban Agriculture

Urban agriculture

Credit: Maria Contesse
Urban agriculture project in Santiago, Chile

Citizens and NGOs from Detroit, USA to Dar es Salaam, Tanzania pursue urban and peri-urban agriculture (UPA) on vacant lots, in city parks, or on rooftops in congested cities like Beijing or Hong Kong, China. This can improve food security, nutrition access and community engagement. UPA benefits mitigation; locally grown food reduces transport distances, closes resource-waste cycles and sequesters carbon; and adaptation; local food production offers a community-managed green space strategy to improve hydrological cycles, water perforation and stabilize microclimates.

Eco-system restoration

urban restoration
Credit: Jennifer Lenhart
Urban restoration programme in Medellín, Colombia

Rio de Janeiro, Brazil and Medellín, Colombia focus on urban (re)forestry to protect their hillsides from landslides; to limit encroachments on these fragile ecosystems they work with local communities, and promote activities such as eco-tourism, education and outdoor recreation. In the aftermath of 2004’s Southeast Asian tsunami, community-based restoration projects engaged coastal communities to (re)plant mangroves in the Mekong Delta (see: the Green Coast model).

Public transport & city cycling

BRT Jakarta

Credit: Jennifer Lenhart
Bus Rapid Transport system in Jakarta

Urban transportation significantly contributes to a city’s GHG emissions. Mobility and accessibility are also important for urban lifestyles, justifying investments in public transport, cycling and walking. But many systems (e.g. underground subways) are costly and complex. As an alternative, Curitiba, Brazil invested in Bus Rapid Transport (BRT) in 1974 which included segregated bus lanes and a system of prepaid tickets. Because of its relative affordability and flexibility, BRT has been adopted in cities from Medellín to Mexico City to Jakarta.

Meanwhile, local governments and NGOs strive to improve city cycling, by investing in cycling lanes, bike sharing schemes (e.g. Velib in Paris) and safety measures. In 1976, Bogotá launched Ciclovía closing central streets to cars for several hours every Sunday. Citizens are encouraged to get out of their cars and on their bikes: for exercise, transport and interaction.

Global attention on local action

Cities are becoming climate change solution spaces and the global scientific and policy communities have noticed. In 2013, the Polish COP19 Presidency and UNFCCC hosted the first ‘Cities Day’ at a COP. In 2014, cities were discussed at the UN Secretary General’s Climate Summit, as one of eight action areas. Cities also feature in the proposed Sustainable Development Goals (proposed goal 11). Additionally, the IPCC in its 5th Assessment Report, recognises cities as places for actions on mitigation and adaptation.

Cities prove that actions to address climate change are not just possible, they are happening, but still many obstacles remain, which will undoubtedly colour negotiations in Lima. Perhaps a stronger focus on urban actions could offer the needed motivation, leading us one step closer to a global agreement next year in Paris.

A few lessons…

While each city encompasses a unique set of challenges and solutions, there are common lessons.

  • Cities should enact collaborative multi-stakeholder processes to develop and implement urban climate strategies; these may offer innovative and locally-appropriate solutions, while increasing ownership. Still, some local government steering, at least initially, remains important.
  • Cities and urban actors already engage in urban climate strategies; however some strategies are not framed as climate relevant – urban agriculture is one example. Communication strategies should bring to light what urban citizens can do to address climate change, as well as part of what they are already doing. Doing so can tangibly demonstrate existing actions, while empowering urban citizens and other actors to engage further.
  • Urban climate strategies should be linked to a city’s sustainability strategies to seek synergies and address multiple goals simultaneously.
  • While much is happening in cities to address climate change, much more work and investment are still needed, especially in the face of rapid urbanization. Moreover, cities need to continue to work together and learn from each other. For this, there are many city-based resources available (see selected research networks: Urban Climate Change Research Network; city networks: ICLEI, 100 Resilient Cities; news media sources: Guardian Cities; and UN resources: UNFCCC’s Cities News and UN-Habitat’s Cities and Climate Change Initiative).

About the author
Jennifer Lenhart is a PhD Candidate at Wageningen University’s Environmental Policy Group. You can read her blog: and follow her on Twitter: @jenn_lenhart