30 years of climate summits: Have they made a difference?

The next United Nations climate conference COP27 will be held in the Egyptian resort town of Sharm el-Sheikh on November 6, 2022. It will mark the 30th year of UN climate negotiations since world leaders gathered at the Earth Summit in Rio de Janeiro, Brazil in 1992. What’s on the agenda in 2022 and how has that changed after decades of talks?