Energy 16 December 2015 Cities, not nation-states, are the things that can save us from climate change The Paris agreement will be for nothing if our cities don't have the right leaders. Photo: Getty Images Sign UpGet the New Statesman\'s Morning Call email. Sign-up The nations have spoken. Now is the time for implementation. The Paris Agreement is historic. At last, the vast majority of the nations of the world have come together in what we hope will be seen in future as the turning point in the fight against global warming. By the end of the year, global temperatures will have already risen 1C above pre-industrial levels. If all the pledges agreed on Saturday were realised, warming would still rise to 2.7C by the end of the century. The agreement includes a rachet mechanism under which the targets agreed this past weekend will be reviewed every five years, but there is no guarantee. This means we must not only meet our targets but exceed them. The best hope of that is in our cities. Nations are crucial for making international agreements and setting national targets. But when it comes to practical action on the ground, cities are centre stage. The world is urbanising quickly and 75 per cent of all greenhouse gas emissions come from cities. They can deliver – and even exceed – those targets. The battle against climate change will be won or lost in cities. Since 2009, cities across the globe have taken over 10,000 actions. Climate Action in Megacities 3.0, a report from the C40 in partnership with Arup, is a definitive assessment of how the world’s leading mayors have taken on the urgent challenge of climate change. It presents major new insights into the current status, latest trends and future potential for climate action at the city level. The report highlights practical and replicable examples, like Portland’s decision to issue Green Bonds from 2016 to finance LED retrofits and other sustainability projects, and Athens’s creation of a new internal coordinating body to ensure sustainability goals are integrated across all city departments. Ho Chi Minh City is collaborating with Rotterdam to shift from planning a climate change adaptation strategy to implementing it. With that level of ambition and vision in cities across the world, it is disheartening that London has failed to meet its own ambitions. The failure was laid bare in recent report from the London Assembly Environment Committee, on which I sit. Could Do Better found that Mayor Boris Johnson is not just shy but actually a long way short of his target. He is missing it because he has failed to deliver his programmes on domestic and workplace retro-fit, and decentralised energy. He has also failed to meet his targets on recycling while at the same time approving a new carbon-emitting incinerator. The Committee’s Carbon Targets Report Card gave him a pathetic four out of ten. This is ironic because London was once seen as a leader and an innovator in tackling climate change. London is the city that created the C40 ten years ago when I was deputy Mayor. As I visited the Cities and Regions Pavilion at COP21, I met city leaders from across the world who were blazing a trail on everything from energy efficiency to street trees. It is vital that London returns to its place amongst those trailblazers. This has never been more important than now. The decisions we take on consumption and infrastructure over the next five are critical because the world will be “locked-in” to sufficient future emissions to exceed the globally safe carbon budget, says the C40. That’s why I am pleased mayoral candidate Sadiq Khan wants to reignite London’s ambition. Whilst in Paris, Sadiq pledged that under his leadership, London will rejoin ICLEI – the global association of city and town governments focused on sustainability. He made this commitment, in addition to continuing our relationship with the C40, because he understands the importance of collaboration to accelerate action, such as procurement alliances between cities and the private sector to bring down the price of new technology. Sadiq believes in an active and entrepreneurial City Hall that can work to put London at the leading edge of the fight against climate change. He has already made a series of green pledges, including moving towards an all-electric bus fleet and requiring ambitious environmental standards on new build housing and developments. He will work with the private sector to invest in the huge potential for jobs in the low-carbon industries, which is a growth sector in the economy. He will be a mayor who realises that when cities act, the world wins. Nicky Gavron is a member of the London Assmembly. › Don't moan about the media - it makes you look like a loser Subscribe For more great writing from our award-winning journalists subscribe for just £1 per month!