For those of you who are keeping up with environmental issues, the World Bank has just published its “Little Green Data Book 2009”. This latest edition points out that the world’s cities are the main drivers of global warming because most economic activity takes place in urban areas. Since cities have become hubs of relative affluence, their greenhouse gas emissions have risen. This has been one of the reasons that developed countries have produced more greenhouse gases than developing countries.

However, the World Bank notes that this level of economic activity is spreading as urbanisation is spreading throughout the world, and it is estimated that by 2050 no less than 70% of the world’s population will live in cities. Unless there is a change in the use of energy greenhouse gases will rise significantly, as cities obtain about 72% of their energy from coal, oil and natural gas. On the other hand cities are the main users of renewable energy but this is still from a very small base. One interesting point is that where populations are living in more dense city centres they are producing, on average, 30-50% less greenhouse gas emissions that those living in outlying suburbs.

The World Bank also notes that the increasing urbanisation which is will be continuing in India and China in the coming years will result in an increase in emissions of carbon dioxide, although their per capita levels will be lower than those of developed countries. Also, lessons will be able to be learned from the successes of countries such as Germany and Sweden which have made dramatic reductions in their emissions over the last 40 years.

The Bank has also warned that 360 million people live in low-elevation coastal zones, making them exposed to potential rises in the sea level. This can be seen in the graphic below.

It is noted that scientists have estimated that sea levels rose by 0.17 meters during the 20^th century and could rise by a further 1 meter during this century, especially if there is a major melting of the Antarctic ice sheet. If this happens it will be far more difficult for developing countries to respond to the changes.