The Gulf of Maine experienced one of its hottest years on record in 2023, though not quite at the level of previous years.
According to the Gulf of Maine Research Institute, the area's annual average sea surface temperature was 52.6 degrees, nearly two degrees above normal, and the fifth-warmest year on record.
Dave Reidmiller, director of the Climate Center at GMRI, said it's not entirely clear why temperatures didn't rise faster at a time when global temperatures reached record levels.
But he said he expects the Gulf to keep getting warmer, unless global greenhouse gas emissions are substantially reduced.
"We're going to continue to see inter annual variability, kind of that bouncing around that long term trend line. But that trend line is undeniable. It's going up, and it's going up quickly here in the Gulf of Maine," Reidmiller said.
The Gulf is one of the fastest warming ocean regions on the planet, and experienced its two warmest years on record in 2021 and 2022.
Reidmiller said the region experienced three marine heatwaves last year, including one of the longest his organization had ever recorded, lasting 113 days from January through May.
"Things changed a little bit, starting around late spring into May. Where temperatures were still above average, but not record-breaking warmth, and not marine heatwave warmth," he said.
Since 1982, sea surface temperatures in the Gulf have increased by an average of about nine-tenths of a degree per decade, nearly triple the rate of oceans worldwide.
