While the price for rolling back emissions will certainly be high, the costs for not doing so are far greater, including the possibility that worldwide temperatures could go up by as much as 5 degrees centigrade, a level that might make much of the world unlivable for human beings.
A jump of that magnitude would be similar to the kind of temperature rise the world experienced at the end of the Permian Era, 250 million years ago. Called the “Great Extinction,” it killed 96 percent of life in the sea and 70 percent on land.
A major reason for the Permian die off was the expansion of cyanobacteria, which produce a toxic cocktail that can kill almost anything they come in contact with. Such cyanobacteria blooms are already underway in more than 400 places throughout the world, including a large dead zone in the Baltic Sea. Some New York lakes have become so toxic that the water is fatal to pets that drink from them.
https://fpif.org/climate-catastrophe-comes-for-europe/
https://blog.ucsusa.org/don-anair/administration-goes-after-states-for-protecting-environment