I usually count the "Earth" as separate from the ecosystem. And certainly there is going to be a massive reduction in biodiversity, with a lot of the species w

I usually count the "Earth" as separate from the ecosystem. And certainly there is going to be a massive reduction in biodiversity, with a lot of the species we value a lot going extinct, but overall the ecosystem will not go kaput. Humans will have to drastically restructure their land use, for example a lot of Midwestern farmers are going to go broke as they adjust to a new climate. Some cities and states like Florida will be in dire straights with 10 feet of sea level rise, which will be a nearly unimaginable expense to relocate. And then all throughout the world we will have absolutely massive migrations of people, along with draught, crop failures, etc. This will result in wars and massive social disruption. Europe can barely deal with a very small number of refugees as it is. Once a country like India becomes unlivable in large areas, there's little telling how countries will react.