 The eruption of Tonga's underwater volcano in 2022 may raise global temperatures, raising the risk that at least one year in the next five will exceed the 1.5 degree Celsius threshold. Fizz.org, January 25th, 2023 models show Tonga eruption increases chance of global temperature rise. Forbes, January 30th, 2023. The problem is the blast emitted 50 million metric tons of water into the atmosphere that's likely to mess with climate for years.