Cities are being unfairly blamed for most of humanity's greenhouse gas emissions and this threatens efforts to tackle climate change, warns a study in the October 2008 issue of the journal Environment and Urbanization.

The paper says cities are often blamed for 75 to 80 percent of emissions, but that the true value is closer to 40 percent. It adds that the potential for cities to help address climate change is being overlooked because of this error.

"Blaming cities for greenhouse gas emissions misses the point that cities are a large part of the solution," says the paper's author, David Satterthwaite, a Senior Fellow at the International Institute for Environment and Development (IIED). "Well planned, well governed cities can provide high living standards that do not require high consumption levels and high greenhouse gas emissions."

United Nations agencies, former US President Bill Clinton's climate change initiative and New York Mayor Michael Bloomberg have all stated that between 75 and 80 per cent of emissions come from cities.

Satterthwaite used data from the Intergovernmental Panel on Climate Change to show that only two-fifths of all greenhouse gases from human activities are generated within cities.

Agriculture and deforestation account for around 30 percent, and the rest are mostly from heavy industry, wealthy households and coal, oil or gas fuelled power stations located in rural areas and in urban centres too small to be considered cities.

But the paper also highlights how it can be misleading to allocate greenhouse gas emissions to places. For instance, emissions from power stations should be allocated to those that consume the electricity, not the places where the power stations are located. Emissions generated by industries should likewise be allocated to the person consuming the goods the industries produce.

"Consumer demand drives the production of goods and services, and therefore the emission of greenhouse gases," says Satterthwaite.

"Allocating emissions to consumers rather than producers shows that the problem is not cities but a minority of the world's population with high-consumption lifestyles. A large proportion of these consumers live not in cities but in small towns and rural areas."

In addition, allocating greenhouse gas emissions to consumers increases the share of global emissions from Europe and North America and highlights the very low emissions per person of most city inhabitants in Africa, Asia and Latin America.

In general, wealthy people outside cities are responsible for more greenhouse gas emissions than those in cities as they have larger homes that need to be heated or cooled, more automobiles per household and greater automobile use.

"The way cities are designed and run can make a big difference," says Satterthwaite. "Most cities in the United States have three to five times the gasoline use per person of most European cities but not three to five times the living standards."

Satterthwaite points out that cities offer many opportunities to reduce per capita greenhouse gas emissions, such as by promoting walking, bicycling and public transport and having building designs that require much less energy for heating and cooling.

"Achieving the needed reductions in greenhouse gas emissions worldwide depends on seeing and acting on the potential of cities to combine a high quality of life with low greenhouse gas emissions," he says.