Cities contribute to and are affected by climate change hence the need for cities to develop sustainably. UN Habitat avers that
The future of hundreds of millions of people in urban areas across the world will be affected by the different impacts of rapid urbanization and climate change. The impacts will vary depending on the form of settlement, geographic considerations and the nature of the local economy. The overall vulnerability of human settlements will increase as confirmed by various scenarios which project that further global warming over the next decades is inevitable.
The adaptive capacity and the capability of systems to actively and adequately respond are largely influenced by wealth, availability of technology, appropriate decision-making capabilities, human capital, social capital, risk spreading (e.g. insurance), ability to manage information, and the perceived attribution of the source of stress. Climate change brings new challenges, which impact on the natural and built environments and aggravates existing environmental, social and economic problems. Clearly these changes will affect different aspects of spatial planning and the built environment, including external building fabric structural integrity, internal environments, service infrastructure, open spaces, human comfort and the way people use indoor and outdoor space. Coupled with the challenges of rapid urbanization, climate change impacts will undermine country efforts to achieve the goals of sustainable development.
Further the World Bank explains why climate change is an urgent agenda for cities
First, climate change is a cumulative process. The longer one waits to reduce GHG emissions, adopt energy efficient systems, or retrofit buildings, the steeper is the curve and the harder to reverse the trend. Pollution will only get worse, congestion more intractable, and urban heat islands more pernicious. “Act now” seems to be the only plausible response.
Second, embracing the climate change agenda now makes eminent sense from an individual city’s perspective, be it economic, social, or political. It shows that the city is part of the global sustainable development agenda. By belonging to a “green cities”club, the city is branding itself as progressive,responsible, and intelligent. This so-called green cities club need not be limited to richer cities. Additionally, climate change policies lead to lower energy costs, ensure a higher quality of life (for example, improved air quality, increased walkability with density, more parks, and fewer cars), and attract more human capital and private investment.