Sprawling cities will put the world under pressure, says Nina Chestney
EXPANDING cities threaten to eat up a swath of land the size of France, Germany and Spain combined in less than 20 years, putting the world under even more environmental pressure, experts have said.
Cities are growing to accommodate a rising global population and as countries like China, India, and Brazil pursue fast economic growth.
The world’s cities are currently on track to occupy an extra 1.5m sq km by 2030 — equivalent to France, Germany and Spain combined — spelling growing greenhouse gas emissions and resource demand, experts said at the “Planet Under Pressure” conference in London.
“The way cities have grown since World War II is neither socially or environmentally sustainable and the environmental cost of ongoing urban sprawl is too great to continue,” said Karen Seto, associate professor of the urban environment at Yale University.
“The North American suburb has gone global, and car-dependent urban developments are more and more the norm.”
The UN sees global population rising to 9bn people by 2050 from 7bn now, adding about 1m people each week.
Most of the growth is expected to come in urban centres with migration from rural areas potentially adding another 1bn people to cities.
That would increase the total urban population to 6.3bn people by 2050 from about 3.5bn today.
Over 70% of current carbon dioxide emissions already come from cities.
Urban emissions are forecast to grow to 36.5bn metric tonnes by 2030 if no action is taken, from 25bn in 2010 and 15bn in 1990.
Urbanisation cannot be stopped, but climate experts argue there is plenty of scope for improving the way cities are planned, developed and run.
“Everything being brought into the city from outside — food, water, products and energy, need to be sourced sustainably. We need to rethink the resource flow to cities,” said Sybil Seitzinger, executive director of the international geosphere-biosphere programme at the Royal Swedish Academy of Sciences.
New cities offered an opportunity to rethink urban planning while established ones could become more efficient through technology such as time-adjusted toll systems to cut traffic congestion, said Shobhakar Dhakal, executive director of the Tokyo-based Global Carbon Project.
Congestion wastes fuel, time and causes pollution.
It costs world economies an estimated 1%-3% of gross domestic product and costs New York alone about $4bn (€3bn) a year in lost productivity, experts said.
Utility meters and sensors that monitor power generation network capacity and electricity supply and demand can also help conserve energy.
Urban planners can also target more efficient land use, better building standards and policies to promote public transport over car use.
Some cities have made efforts to improve their green credentials, such as Iceland’s capital Reykjavik.
The city depends on geothermal energy and hydro electricity for its energy needs.
Vancouver in Canada sources 90% of its energy from renewable sources.
These include wind, solar and tidal energy.
The city has also developed a 100-year sustainability plan.
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