By Megan Rowling
BARCELONA, Sept 19 (Thomson Reuters Foundation) - Withefforts to make buildings, transport, energy and wastemanagement greener, cities could cut their planet-warmingemissions nearly 90% by 2050, producing close to $24 trillion inreturns, a coalition of 50 organisations said on Thursday.
But to realise the benefits of investing in low-carboninfrastructure and services, cities both large and small willneed support from national governments, which has often beenpatchy up to now, they added.
Cities are vital to limit global warming because they arehome to more than half the world's population, produce 80% ofgross domestic product and generate three-quarters of carbonemissions, said a report issued ahead of Monday's U.N. climateaction summit.
Low-carbon measures in cities - based on already availabletechnologies such as electric buses - could deliver over halfthe emissions cuts needed to keep global temperature rise below2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrialtimes, the report said.
"It is possible and realistic to realise net-zero urbanemissions by 2050," U.N. Secretary-General Antonio Guterres saidin a statement on the report, which was produced by theCoalition for Urban Transitions.
"But to get there, we will need the full engagement of citygovernments combined with national action and support.”
Los Angeles Mayor Eric Garcetti told journalists his cityhad been installing huge amounts of solar power, supportingfirefighters grappling with record California forest blazes, andcreating jobs in electric and other green transport.
The second-largest city in the United States was pushingforward, he said, despite hostile signals on climate action fromPresident Donald Trump, who wants to quit the Paris Agreement.
"In my country - where the Trump administration is activelypulling us back in the fight against climate change - mayors andcities are still doing the work that serves our residents andour futures," Garcetti said.
Germany, by contrast, has a national climate initiative thathas invested 905 million euros ($1 billion) in 29,000 localprojects over the last decade, said environment minister SvenjaSchulze.
These range from upgrading street lights to setting up"mobility stations" with bike-parking and car-sharing nearpublic transport stops.
Nicholas Stern, a professor at the London School ofEconomics and co-chair of the Global Commission on the Economyand Climate, said cities, as "a source of creativity andinnovation", could lead the global response to climate change.
Ramping up investment in adopting renewable energy, ditchingdirty construction materials and other low-carbon measuresequivalent to 2% of global GDP per year would bring a four-foldfinancial return by mid-century, he told journalists.
But making cities more liveable, less polluted and easier toget around would also deliver additional benefits in terms ofbetter health, time saved and higher economic growth, he added.
"Compact, connected and clean (cities) are much moreattractive, creative, dynamic places to live and work," he said,adding they would draw in the best talent in a world wherelabour, capital and ideas were mobile.
EMERGING ROLE MODELS
The report also highlighted the need for action infast-expanding urban areas in developing countries, with citypopulations expected to grow by 2.5 billion over the next 30years in Africa and Asia alone.
It gave examples of countries and cities that have made bigstrides in recent years to improve housing, transport andservices for slum residents which also benefit the environment.
They range from Medellin's famous cable-car system thatservices deprived neighbourhoods, to doorstep waste collectionand recycling that has turned Indore's smog-ridden streets wherepeople defecated in the open into India's cleanest city.
Stern said there were many good models for developing-worldcities to emulate, while they should also aim to build their ownsources of finance - from carbon, property and land taxes - toinvest in greener growth.
Sarah Colenbrander, who leads the global programme at theCoalition for Urban Transitions, said efforts to tackle climatechange would not work without addressing poverty and inequalityamong city residents.
To that end, it would be important not to neglect smaller,poorer cities of under 750,000 people, which could provide morethan half of projected emissions reductions but lack resourcesand depend most on national standards and support to transform.
"It really is an opportunity not to be missed," she added.($1 = 0.9050 euros)(Reporting by Megan Rowling @meganrowling; editing by ZoeTabary. Please credit the Thomson Reuters Foundation, thecharitable arm of Thomson Reuters, that covers humanitariannews, climate change, women's and LGBT+ rights, humantrafficking and property rights. Visit http://news.trust.org/climate)