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.

One reason cities do not have higher greenhouse gas emissions is that they no longer concentrate most heavy industries – including cement fabrication plants, petroleum refineries, fertilizer plants and pulp and paper mills. Most mines and energy-intensive processing such as copper and aluminium smelters are also outside cities. In addition, in much of Europe and North America, a large proportion of wealthy high-consumption households choose to live outside cities. This helps explain why cities like New York have much lower greenhouse gas emissions per person than the average for the USA – although this is also linked to the way in which compact cities with good public transport lower private automobile use per person.

Examples of cities being incorrectly blamed for 75 to 80 of greenhouse gas emissions:

"Large cities take up only 2% of the Earth's land mass, but they are responsible for about 75% of the heat-trapping greenhouse gases that are released into our atmosphere" Clinton Climate Initiative, William J Clinton Foundation [link]

"Cities consume 75 per cent of the world's energy and produce 80 per cent of its greenhouse gases" – Mayor Michael Bloomberg delivers Keynote Address at the C40 Large Cities Climate Summit, May 2007 [link]

"Cities are responsible for more than 75 per cent of global greenhouse gas emissions" – Paul Dickinson, The Carbon Disclosure Projects, "The Role of Cities in Managing Greenhouse Gas Emissions" [link]

"….cities were responsible for 75 per cent of global energy consumption and 80 per cent of greenhouse gas emissions" – Anna Kajumulo Tibaijuka, Executive Director of the United Nations Human Settlements Programme (UN–HABITAT), in a speech to the United Nations, 62nd General Assembly, Second Committee [link]

"Cities have a central role to play in tackling climate change as they are responsible for 80 per cent of international greenhouse gas emissions and consume 75 per cent of the world's energy" – Mayor of London website [link]

Note: If no author is given, the source is cited instead.

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