Contributor(s): Rachel Kyte | The Paris Accord, the hoped for ambitious agreement, to be decided at the 21st Convention of the Parties of the UNFCCC, this December, will set us on a new pathway towards zero carbon growth. When the negotiators go home, what messages will they have sent to economic actors globally? How will an orderly transition to zero carbon growth be managed and financed? In response to overwhelming scientific consensus and a compelling economic case that we need to change the course of our carbon history, who will CEOs, Heads of State and others respond to the question “when you knew, what did you do?” Rachel Kyte (@rkyte365) is a World Bank Group Vice President and Special Envoy for Climate Change. As a leading advocate for action to combat climate change because of its intrinsic link to poverty and development, Ms. Kyte is the leading figure for the World Bank Group in efforts to campaign for an ambitious agreement at the 21st Convention of the Parties of the UNFCCC this December. She is leading work on climate change adaptation, mitigation, climate finance, and disaster risk and resilience across the institutions of the World Bank Group, including IBRD, IDA, IFC, and MIGA. Professor Samuel Fankhauser is Co-Director at the Grantham Research Institute on Climate Change and the Environment and Deputy Director of the ESRC-funded Centre for Climate Change Economics and Policy, both at the London School of Economics. The Grantham Research Institute on Climate Change and the Environment (@GRI_LSE) is a research centre at LSE. The Institute’s research looks at the economics of climate change, and aims to inform policy and academic debate.