This story was originally published by Grist and is reproduced here as part of the Climate Desk collaboration. Climate change and sustainability are on the agenda for this week’s Democratic National Convention, which started Monday in Chicago, with speakers including Interior Secretary Deb Haaland and Representative Alexandria Ocasio-Cortez. But climate-minded delegates and voters might be wondering what’s so sustainable about a gathering that pulls in 50,000 people from across the country, most of them by plane. In other words, convention organizers want to make sure they walk the talk people will hear this week.