We cannot lose our green and our blue: climate change threatens our urban environment.

• Author: Maia, Cesar

Global climatic change will affect all aspects of social life in the twenty-first century. The measures necessary to confront the challenges brought about by global warming and to mitigate its impact go far beyond the indispensable technological transition in the production process and changes in consumption habits of individuals. The future of cities and what we now call "urban" will also undergo transformations.

In the economic, social and political realms, these changes will be profound. The economy will have to progressively incorporate environmental costs into its budget. There is no technological miracle that could help avoid the need for a radical reconversion of the sources of energy--the end of fossil fuels will be one of the realities of the century. Of similar impact will be the emergence of a global perspective on the issue of social inequalities. In the last few decades, we witnessed global efforts to combat poverty, but inequality in the access to income remained an internal matter of national territories. We live in a world where the United States and other developed countries are responsible for two thirds of greenhouse gas (GHG) emissions, while approximately 900 million Africans are responsible for only 3 per cent. However, loss of agricultural productivity, droughts and flooding will adversely affect Africa more. This applies to all poor populations, who are much more vulnerable to the impacts of global warming.

Politics will also change in a significant manner. Following the globalization of markets, there are two historical processes that constitute an international civil society demanding the evolution of world governance: the incorporation into the global economy budget of the costs of short- and long-term goods and services provided by nature, which is until now neglected; and social inequality worldwide. The majority of the world's population lives in cities. In fact, it is a very heterogeneous reality, so much so that the geographic and statistical definitions of what is, or is not, consider "urban" vary considerably among regions, since there are no patterns that may be compared internationally.

The revolution in communications technology per se impels a great transformation in urban life, but global climate changes will highly accelerate this process. The reorientation of the means of energy production, the modes of production and consumption of goods and services, and an acceptable per capita production of...