The geopolitics of climate change and (dis)agreements to reduce greenhouse gas emissions is complex. It’s a lot easier to understand all this chaos if you watch this cartoon with lots of humming.
In 1997, multiple nations signed the Kyoto Protocol. However, the USA later demanded that all countries cut emissions or it wouldn’t. The developing countries, like China and India, refused to cut emissions too, because they were still growing. They said the developing countries caused global warming, so they were responsible for fixing it. Today, a compromise situation has prevailed. Rich countries pay developing countries to reduce their carbon emissions, so rich countries don’t have to cut so much.