Carbon offsets — whereby one party pays another party to reduce carbon emissions — are an extremely convenient thing to have for people, businesses, and institutions that have money to spend, want to do something green, and either won't or can't reduce their own emissions.So offset markets have flourished for decades, even in the face of investigation after investigation, exposé after exposé, showing that the emissions reductions they represent are dubious or outright fraudulent.Things may be coming to a head, though, especially as it slowly sinks in that the Paris Agreement in many ways renders the entire enterprise of offsets moot. If everyone is trying to get as close as possible to zero emissions by 2050, what is gained by trading those reductions back and forth?A white paper digging deep into these subjects was recently published by none other than Joe Romm. Romm has a PhD in physics from MIT and worked at the Department of Energy in the 1990s, but most people in my world know him as one of the earliest and most influential climate bloggers. He’s also authored numerous books on climate solutions.As of earlier this year, he is now a senior research fellow at the University of Pennsylvania Center for Science, Sustainability, and the Media, being run by climate scientist Michael Mann. His first report is on offsets, and it’s a doozy. I called to talk with him about the role offsets have played in the past, the reforms the UN is attempting to make to them, and their future in a post-Paris world. Get full access to Volts at www.volts.wtf/subscribe