A lot can change in a year. As global political shifts have given way to a new world order, the role of citizens, businesses and policymakers in the pursuit of progress on the green agenda has also evolved. The decision of the US president, Donald Trump, to withdraw from the Paris Agreement, and the subsequent defiance from certain state legislatures and multinational companies demonstrates the expanding role of individuals and corporates in driving progress in a globalised world. At the same time, Brexit is narrowing the bandwidth of European legislators, threatening to delay critical progress on policy. But with the effects of climate change increasingly apparent across the world, can we really afford to wait? Does the onus fall upon businesses and consumers to pick up the slack where governments have failed? How can capital markets be reformed to price in the risks related to sustainability on a timeframe that reflects the seriousness of the risks and the urgent need for action? And how can collaboration between those with ideas and those with resources be stepped up across sectors and countries? The Economist Events’ third Sustainability Summit will convene business leaders, policymakers, scientists, researchers, advocates and investors to gauge the scale of the task, and work out how best to lead and encourage co-operation on the path to progress.