Energy is the engine of the global economy — and the largest contributor to climate change. Approximately eighty percent of the the worldʻs energy use comprises fossil fuels, and contributes more than three-quarters of climate-warming emissions. The good news is that the rapid growth and steadily declining costs of solar, wind, batteries, and other zero-emission energy technologies offer the potential to dramatically phase out the use of coal, oil, and natural gas in the coming years. The Transatlantic Climate Alliance works to accelerate this transition, by convening subnational policymakers with industry, academia, small business leaders, the cleantech sector, and others to communicate best practices and catalyze change.