Under the auspices of the nonpartisan Club de Madrid, the world’s largest forum of former democratically-elected presidents and prime ministers, an open letter—signed by Carlos Alvarado, former President of Costa Rica; Mari Kiviniemi, former Prime Minister of Finland; Chandrika Kumaratunga, former President of Sri Lanka; former UN Secretary General Ban-Ki Moon; and dozens of others—calls the climate crisis “a defining challenge of our time” and urges current leaders to “place the question of fair taxation of fossil fuel company profits firmly on national and international agendas” before it is too late.