13 themes for sustainable urban development


Urban Solutions Themes 

How can cities adapt water, air, mobility, or building systems to reduce ecological footprints and protect biodiversity? Some answers on how to begin can be found within these our learning cases, organized around 13 vital themes: air, water, food, ecosystem services and biodiversity, housing and buildings, mobility and accessibility, consumption, waste and sinks, energy, climate change mitigation, climate change adaptation, governance and citizenship, and resilience.


Air quality is a major concern for cities, and for good reason. Air pollution seriously affects human health – with potentially deadly and disabling effects. Air quality is crucial for ecosystems that cities depend on, forests and agriculture, for example. So air pollution presents a major economic threat. 


Water holds the biosphere together - it links many environmental issues - pollution, biodiversity, food, energy, climate regulation, and many more. How well we use, manage, waste, or pollute water can determine the sustainability of our environment. Water also connects many issues in urban systems. 


The basic need for food is interconnected with other needs and ecosystem services – air, water, waste management, energy, and more. Problems in one system tend to multiply into other areas. But solutions can also be multiplied. For reasons of food safety and health, cities are increasingly engaging in food policies and urban farming.


Many of cities’ basic needs depend on nature’s ecosystem services. These in turn are dependent on biodiversity. A wide range of ecosystem services come from the natural spaces in and around cities. They clean the air and water, temper floods, provide water and food, and conserve biodiversity.


Buildings account for almost 40% of carbon dioxide emissions globally, and in bigger cities up to 80%. Many cities have turned to retrofitting buildings as one of the most costeffective ways to make good on promises of greenhouse gas reductions. Most energy-efficiency upgrades pay for themselves through energy savings.


Cities need space – and people need to access the city. Mobility and accessibility are tied to a range of other choices that affect ecological footprints and nature conservation. How much land will be used, and how much will be left for nature and agriculture? What energy sources will be used and what kinds of emissions into air, water, and soils?


Cities import huge amounts of resources from other places. As cities’ footprints spread and join in complex supply chains, urban dwellers may unknowingly cause major environmental damage through their consumption patterns. We are currently consuming nearly 50% more than our planet can sustainably provide. 


Given that we have one interconnected planet, we cannot throw stuff away and forget it. It is still there, and can come back in our air, our water, and our food. Expanding the concept of reduce, reuse, recycle should include another ’r’ – repair, while sinks must be properly maintained as the part of our environment that can uptake some waste and pollutants.


Preventing climate change and building resilience in cities require real energy revolutions, shifting towards greater efficiency, and renewable energy use. Cities are leading actors in the transition from fossil fuels to alternative energy sources, as well as "negative-cost" strategies like building retrofits and smart metering.


Climate change is one of the largest threats facing people and nature. Climate is basic to our life systems – yet through our actions, humanity is causing the climate to change dangerously. Cities have risen to the challenge and are setting some of the world’s most ambitious goals for reducing their impact on the climate.


Global climate change carries huge risks – for food security and water security and other life-supporting services. Some impacts will be felt distinctly at the city scale: extreme weather events like heat waves, floods, storms, landslides, and droughts. Urban populations are particularly vulnerable to extreme weather events.


In cities, everything is closely connected, thus problems tend to multiply, though so too can smart solutions. Cities can exploit positive synergies, or struggle with negative ones. Those that are well-governed and well-designed are usually more sustainable along every dimension. Responsible decisions for people and environment often pay for themselves.


The new field of resilience has grown with the approach of catastrophic climate change. Resilience can be defined as the ability of a system to withstand and recover from hazards. The question is how resilient cities will be in the face of climate change and other environmental problems like air pollution or natural disasters.