Cynthia Rosenzweig, of the NASA Goddard Institute for Space Studies, is co-editor of a report on climate change and cities released in June of 2011. Over 100 experts contributed to the work, which details how climate change will affect – and is already affecting – many of the world’s most important cities, including Athens, Dakar, Delhi, Harare, Kingston, London, Melbourne, New York, São Paulo, Shanghai, Tokyo, and Toronto. Every city faces a different scenario, according to Rosenzweig. She talked more about New York City, where she lives:

New York. Image Credit: srbyug

New York put together about 40 different agencies that run critical infrastructure of New York – the subways, trains, water systems, even telecommunications – and created a climate change task force that looked at the risks of a change in climate, and then brought forward, across all those different types of infrastructures, plans and ideas for how they can develop a climate-resilient city. New York is working to do good planning for climate extremes, which is one of the big issues in New York, as a coastal city.

She told EarthSky that New York is also trying to reduce its greenhouse gas emissions. She said:

New York has also committed to a target of 30% reduction in greenhouse gases by 2030. So you can see that New York is working on the adaptation side, and the mitigation side.

Cities are taking the lead in action on climate change, Rosenzweig said, and cities in many nations are working toward similar goals.

Rosenzweig said that every city is in a different stage, with regard to its climate change response. She talked about the coastal city of Lagos, Nigeria – one of the largest cities in Africa – which, she said, is in the very early stages of trying to figure out how it will be affected by climate change. She said that a large percentage of the population lives in slums. She said:

Lagos, Image Credit: claudionapoli

Some of those settlements are built on stilts out in the lagoons, in very low-lying areas. In Lagos, city leaders are working on stepping up to find out about sea level projection, how far inland the coastal flooding would go. This is one of the case studies we’ve done that shows maps of how vulnerable the city is.

So Lagos is beginning to find out. The first step when a city wants to begin to tackle climate change is to do a vulnerability study. Lagos is trying to find out where the riskiest areas of vulnerability are.

EarthSky asked Rosenzweig how a city like Lagos can take action on climate change when it doesn’t have as much money as a city like New York. She said:

“They do it by joining the international groups and with the researchers, the Urban Climate Change Research Network, which I belong to. There are programs through the United Nations. Through the U.N. Convention on Climate Change there is a program which helps to fund adaptation, which came out of Copenhagen.

The city leaders from developed countries, especially, and also developing countries are banding together to bring to the attention of the national and international leaders and negotiators the importance of city action, and funding that action.

Delhi. Photo credit: wili_hybrid

Rosenzweig also spoke of Delhi in India.

Delhi is an inland city, but even the cities that are not on the coast are on some kind of waterways, such as rivers, are prone to flooding. In Delhi, a key vulnerability is a risk of river flooding. There are informal settlements there right along the riverbanks.

Researchers at Columbia University and the City University of New York (CUNY) led the creation of the full report, which is titled “Climate Change and Cities: First Assessment Report of the Urban Climate Change Research Network (ARC3).” Cambridge University Press published the report in May 2011.

According to the report, some key findings that illustrate the urgent need for improved urban preparedness and planning include:

* Urban climate change risk results from a combination of hazards, vulnerabilities, and adaptive capacity. In a dozen major cities, average temperatures are projected to rise between 1°C and 4°C by the 2050s, increasing extreme weather events including heat waves.
* Coastal cities should expect to experience more frequent and more damaging flooding related to storm events in the future due to sea level rise. Particularly at risk are populations like those living in slums located in the lagoons of Lagos.
* In many cities, the quantity and quality of the energy, water, and transport systems will be significantly affected by the projected increases in both flooding and droughts. In developed country cities, leakage from the water supply distribution system can be severe, resulting in system losses of between approximately 5 percent and more than 30 percent. Developing country cities may use informal distribution systems, which can be even more vulnerable but whose loss is not as quantifiable.

Listen to the 90-second EarthSky interview with Cynthia Rosenzweig on climate change and cities (at top of page.)