In year 1750, over 98% of coral reefs (magenta dots) grew in optimal conditions with aragonite saturation greater than 3.5 (blue colors). Such water is rapidly disappearing and will be gone in several decades if current carbon dioxide emission trends continue. Atmospheric CO2 levels are 280 ppm, 380 ppm, and 550 ppm for years 1750, 2007, and 2050, respectively.
