Arnold Schwarzenegger and Michael Bloomberg told a meeting of city leaders how green policies were helping the fight against climate change. At city level, Copenhagen gave real cause for optimism, says Mike ScottDecember's UN climate summit in Copenhagen generated huge expectations, which were in general not fulfilled. The disappointment was counterpointed by events occurring across town, where leaders of some of the world's largest cities - about 70 city leaders representing 700 million people - met for a Mayors' Summit.
In contrast to the confusion and conflict at the Bella Centre, the meeting "was completely co-operative, collaborative and unanimous about the direction to go in," says Mark Watts, a director at engineering consultants Arup.
"The discussion was all about how we deliver emissions cuts."
The thorny negotiations and the disappointing outcome at COP15 looks all the more bewildering when compared with the very real progress being made at city level, added Peter Lacy, head of sustainability, Europe, Africa and Latin America at Accenture. "Arnold Schwarzenegger [the governor of California] and Michael Bloomberg [the mayor of New York] were talking about tangible, concrete actions they are taking."
The conference of city leaders represents a significant point of optimism for the future of the fight against climate change because urban areas are on the front line of the global warming battlefield, according to Cynthia Rosenzweig, head of climate impacts group at the NASA/Goddard Institute for Space Studies. "Cities are
already warmer because of the urban heat island, they have high levels of air pollution which are exacerbated by the heat and many are on the coast and so will be most seriously affected by sea level rises."
At the same time, more than half of the world's population already lives in urban areas and the trend will be exacerbated as we move towards 2050, points out Lacy.
"Seventy percent of global emissions relate to cities and that is only going to grow," he says. "It is extremely important that cities take action - the majority of efforts around the shift to a low-carbon economy will have to be related to cities."
Urban areas are already taking practical, proactive measures to tackle their emissions, says Dr Rosenzweig. "The city government level is so much more conducive to action because cities understand their vulnerabilities and are able to see the benefits of mitigation and adaptation actions." In addition, cities are hotbeds of technological innovation that make them ideally placed to develop the solutions needed to cut emissions.
Sub-national governments hold more than half the policy and fiscal levers required to deliver the low carbon economy, says Steve Howard, CEO of the Climate Group. "At their best they move faster than national governments and many have led the way for nations to follow.
However, given the deep transformation in our economy that is required we need the active leadership of all levels of government and a fit for purpose international deal."
It is crucial that local governments focus on adaptation (dealing with climate change that is built into the system) as well as mitigation (reducing emissions that will cause future climate change), he asserts.
"There's been so much focus on mitigation, but cities are at the forefront of emissions and vulnerability to climate change."
The Mayors' Summit highlighted the variety of actions that cities can take, from plans by Los Angeles to upgrade all its street lighting to LEDs to London's initiative to install the infrastructure for electric vehicle trials. There is still a long way to go, says Lacy, whose firm is leading a smart city pilot project in Amsterdam.
"We are long on isolated delivery activities but short on co-ordinated planning."
Cities need to integrate different themes such as sustainable living, sustainable working, sustainable mobility and sustainable municipalities into their strategies for creating more environmentally friendly cities - at a more detailed level, areas such as energy, water, waste, heating and cooling, buildings, mobility and public safety need to be considered together. Despite being inextricably linked, all of these issues are controlled by different departments and even separate organisations, so cooperation and co-ordination between different stakeholders is vital to ensure a joined-up approach to programme delivery.
For example, the New York task force to tackle climate change involves 40 different organisations, says Rosenzweig, ranging from the Mayor's office to the Port Authority (a bi-state authority split between New York and New Jersey) to federal agencies such as the Environmental Protection Agency, along with many private sector groups such as telecoms companies and energy providers.
One of the most consistent areas of discussion at the summit was the built environment - particularly the need to retrofit buildings, says Arup's Watts. "In New York, 80% of all buildings that exist today will still be in use in 2050, so if it is going to meet its target of an 80% cut in emissions, there must be a significant transformation of the building stock."
Another reason to concentrate on retrofit programmes is that there are financial and quality of life benefits, he adds. New York estimates that its retrofit programme will create 30,000 jobs, while London's retrofit of its public buildings will save about £1M a year that can be reinvested into public services, Watts says.
The other big area to deal with is transport, he adds. "What was interesting about the mayors' meeting was that for the first time, the most talked about topic was not road pricing or new metro systems but cycling." It is appropriate that the focus on cycling should come in Copenhagen, a city that has set itself a target of getting half of its population regularly using a bicycle by 2015, up from 36% currently despite its relatively inhospitable climate.
The emphasis on cycling is not confined to the Northern European countries - London has seen a 100% increase in cycling rates in the past five to six years, while a number of Latin American cities are also pushing the bike as a climate measure. "For many Latin American cities, transport is the biggest contributor to emissions, so cycling is a very cost-effective way of cutting emissions," Watts says.
Mexico City plans to increase the amount of cycling from 1% to 5% of journeys, while Sao Paolo and Buenos Aires are also introducing cycling initiatives.
Cycling and energy efficiency investments are examples of "low-hanging fruit" that cities can invest in relatively cheaply and that will not only cut emissions but also bring knock-on benefits such as cost savings and health improvements.
However, at some point, if cities are serious about dealing with emissions they must look at long-term infrastructure investments - in energy generation, transport, water and waste.
Copenhagen was named Europe's greenest city in the European Green City Index, which was launched on the first day of the COP15 summit. The city is committed to becoming carbon neutral by 2025. Almost all the city's buildings are connected to its district heating system, which was developed as a result of the 1970s oil crisis and almost a fifth of its energy comes from renewable sources.
This figure highlights the limits of what cities can achieve on their own and an area where they are dependent on national policies - Denmark is a world leader in wind energy and is aiming for 30% of its energy generation to be renewable by 2025.
Many cities have seen their use of renewable energy and energy efficiency measures lifted by national policies such as Feed-in Tariffs and building standards.
Arup estimates that only about half of London's plan for a 60% cut in emissions by 2025 can be met through the Mayor of London's powers, with the other half dependent on government intervention.
Another area where Copenhagen finds itself constrained by national policy is in the transport sector. Ritt Bjerregaard, Lord Mayor of Copenhagen, says that there is strong support on the city council for the introduction of a congestion charge, but the national government deems such a measure a tax-raising initiative, which is the preserve of central government. By contrast, cities such as London and Stockholm have been allowed to introduce congestion charges, and have managed to make significant progress in cutting the amount of traffic as a result.
In an example of how different issues need to be considered in tandem to have the maximum impact on emissions, Denmark is looking at how it can integrate electric cars into not just the transport system but also the electricity network as well.
According to German engineering group Siemens, electric cars can play a key role in helping to smooth out the volatility in the grid created by large-scale use of renewable energy such as wind. They do this by providing a market for wind power at offpeak times such as overnight and because they can be hooked up to the grid during the day to feed power back into the system to cover short-term peaks in demand.
There is much that cities can do to become greener, but without supportive policies at a national level, making progress will be an uphill struggle, says Rosenzweig.
"National governments are important for funding the efforts of cities."
However, as Arnold Schwarzenegger told the Mayors' Summit: "We cannot wait for national governments to fight climate change on their own, because then we would have to wait for a long time.
The only way we can be successful is by co-operating."