The earth’s environment has deteriorated over the last few decades in close parallel with the increasing capability of human beings to transform nature with little concern for environmental protection. Since the industrial revolution, the global climate has been ever-changing as anthropogenic activities that release greenhouse gases have intensified significantly. Climate change severely engenders opportunities for a variety of natural disasters such as extreme heat, flooding, bushfire, and drought, and results in severe threats and risks to human beings. Even worse, such environmental deteriorations are posing more significant threats and risks to cities, where the majority of the world population lives. Over the past few years, the significance of city level actions for enhancing climate change mitigation and adaptation are being increasingly recognized. On the one hand, cities are currently responsible for about 70% of global GHG emissions, and this share is expected to further increase in the near future in consideration of the projected increase based on global urbanization trends. On the other hand, cities can provide solutions through economies of scale and efficiency improvements. It is now recognized that unreasonable urban planning and design (e.g. green–blue infrastructure reduction, extreme levels of density, anthropogenic wastes, gas and pollutant release) can not only increase emissions but also aggravate threats and risks, leading to a series of environmental problems such as urban heat islands, urban air pollution, urban flooding, etc., and, consequently, environmental, social, and economic losses. According to a UN projection, about 70% of the world’s population is expected to live in cities by 2050. This means that the coming three decades are particularly important for ensuring sustainable urban development and to avoid becoming locked into undesirable development pathways.

Sustainable urban environmental planning is thus one of the most important pathways toward the mitigation and alleviation of possible climate-induced threats and risks.

Dr. Elise Machline, Director of the Center for Climate Change Policy and Research, is part of the Ecourbanism research network, a website for sharing knowledge and experience about eco-urban neighbourhoods in different parts of the world.