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Researchers lay out new path for science on cities and climate change

An international team of researchers is calling for a new global push to understand the complex connections between the world’s cities and climate change.

That call, published this week in a commentary in Nature, emerges from a growing recognition that cities play a central role in both causing, and potentially solving, climate change challenges worldwide. In the paper, a team hailing from 10 different countries lays out a series of priorities for future research on these critical links. The recommendations include everything from gathering more data on small-sized cities and informal settlements, or slums, to harnessing new innovations like bike-share programmes and skyscrapers made from bamboo.

A bike-share stand in Haikou, China.

“Cities are responsible for 75% of the world’s carbon dioxide emissions from energy use,” says Xuemei Bai, a professor at Australian National University in Canberra and lead author of the commentary. “That figure will only increase as more people live in cities. In that sense, cities will become the battleground for sustainability and adapting to and mitigating climate change.”

Expanding cities

The report’s release comes in the lead up to the Cities and Climate Change Science Conference (CitiesIPCC), which will run from 5 to 7 March in Edmonton, Canada. This landmark international event, co-sponsored by the Intergovernmental Panel on Climate Change (IPCC), will examine how cities can help the world to “bend the curve” on rising temperatures. Future Earth is one of nine partners helping to organise the conference.

The conference is an important one for the global community because cities are growing at an explosive rate, Bai says. Estimates from the United Nations suggest that more than 2 billion more people could live in cities and towns by 2050. Building the infrastructure to accommodate those new urban residents, and upgrading infrastructure in developing cities, could send roughly 226 billion tonnes of carbon dioxide into the atmosphere, she adds.

But urban areas, from mega-cities like Paris to informal settlements like Dharavi on the outskirts of Mumbai, are more than just problems, says commentary co-author Diana Ürge-Vorsatz.

“Cities are the powerhouses of ideas and innovation,” says Ürge-Vorsatz, a professor at Central European University in Budapest, Hungary. “Many of these have been disrupting our business-as-usual. Some of these will contribute to increasing global warming, others could help reducing it significantly.”

To build on those powerhouses, the commentary team lists six priorities that they say the urban research community should focus on in the coming years. They are:

  • Expand observations: Researchers need to collect a lot more data relevant to cities and climate change, especially from small- to medium-sized cities in the Global South.
  • Understand climate interactions: Researchers should grasp how the actions that cities make in one area, such as to clean up air pollution, can have wide-ranging, and sometimes unexpected, consequences for climate.
  • Study informal settlements: Researchers can do a lot to expand information and map how climate change might affect informal settlements and how these communities are adapting to such risks. 
  • Harness disruptive technologies: Researchers will need to increasingly explore how new technologies and other innovations can help urban residents, local governments and businesses to reduce their greenhouse gas emissions.
  • Support transformation: Researchers can develop and examine “bold strategies” for building low-carbon cities, including China’s efforts to build “sponge cities” that absorb water during heavy rains and reduce flooding.
  • Recognise global sustainability context: Researchers will also need to understand how efforts to reduce greenhouse gas emissions in cities can help, or in some cases hurt, other sustainability initiatives – such as the United Nations’ Sustainable Development Goals.

Timber towers

Many cities are already developing creative approaches to meet those six priorities, the authors of the new commentary write. Newcastle University in the United Kingdom, for example, has launched a project that collects roughly one million observations each day from sensors spread across its home city – capturing data on everything from weather to tide levels. Bai and her colleagues recommend creating a series of such “urban observatories” around the world to help cities prepare for worsening heat waves, floods and more.

“We live in an era of big data, yet there is much about our cities we do not yet understand,” says commentary co-author Richard Dawson, a professor at Newcastle University in the United Kingdom. “There is an urgent need to extend the quantity and types of urban data that are collected to understand how cities are changing, and provide the necessary information to support climate change adaptation and mitigation.”

Concept art for a planned skyscraper made of timber in Tokyo. Image: Sumitomo Forestry Co.

New technologies for reducing greenhouse gas emissions also abound: Architects in Tokyo, for example, are planning to build a skyscraper that would top out at close to 350 metres tall and be made largely out of wood – a strategy that would cut down on the emissions generated from producing concrete. Bike-share programmes in a number of Chinese cities have also exploded in popularity, in part because residents can rent, return and pay for their rides from their smart phones.

“Technological and social innovations could offer possibilities for disruptive transformations to make life better in cities and also help communities respond to climate change,” Ürge-Vorsatz says. “But we need a much better understanding of these tool and how to share them among cities.”

Bai, Dawson and Ürge-Vorsatz say that they hope their commentary will inspire a lot of good conversations among participants in next week’s conference. The authors of the commentary all serve on the Scientific Steering Committee for that event, which will inform upcoming work from the IPCC on climate change and cities.