Meltwater pulse 1A

Meltwater pulse 1A (MWP1a) is the name used by geologists, paleoclimatologists, and oceanographers for a Quaternary period of rapid post-glacial sea level rise between 14,700 and 13,500 years ago, during which the global sea level rose between 16 meters (52 ft) and 25 meters (82 ft) in about 400–500 years, giving mean rates of roughly 40–60 mm (1.6–2.4 in)/yr. MWP1a is also known as catastrophic rise event 1 (CRE1) in the Caribbean Sea.

The rates of sea level rise associated with MWP1a are the highest known rates of post-glacial, eustatic sea level rise. Meltwater pulse 1A is the most widely recognized and least disputed of the named post-glacial meltwater pulses. Other named post-glacial meltwater pulses are known most commonly as meltwater pulse 1A0 (meltwater pulse 19ka), meltwater pulse 1B, meltwater pulse 1C, meltwater pulse 1D, and meltwater pulse 2. MWP1a and other periods of rapid sea level rise are known as meltwater pulses because the inferred cause of them was the rapid release of meltwater into the oceans from the collapse of continental ice sheets.