In an address at the Climate Leadership Conference on March 4, 2015, Mr. Rubin spoke about the economic effects of climate change and the costs of inaction. Calling climate change "the existential threat of our age," he called for the adoption of three proposals – revising estimates of the Gross Domestic Product to reflect climate change externalities, disclosure to investors by companies of the costs of carbon they emit that they might be required to absorb, and including in the U.S. government's fiscal projections the future costs of dealing with climate change – to help catalyze a more active response to climate change risks. He first outlined the proposals in a Washington Post op-ed column titled "How Ignoring Climate Change Could Sink the U.S. Economy."