The Gulf of Maine is one of the fastest-warming ocean ecosystems on the planet, according to scientists at the Gulf of Maine Research Institute.
Over the last 30 years, it has warmed at a rate of 0.06 degrees Celsius per year (0.11 degrees Fahrenheit per year)—more than three times the global average. Over the last 15 years, the region warmed at more than seven times the global average rate. At both time scales, the Gulf of Maine warmed faster than 99 percent of the global ocean.
This year has been especially warm, and scientists at GMRI are now saying the Gulf of Maine officially experienced its second warmest-ever day on Aug. 8, when the average sea surface temperature reached 68.93 degree Fahrenheit, just shy of the record set in 2012.
Moreover, this year has officially crossed the threshold for what scientists call a “marine heatwave,” an area of ocean that experiences temperatures above the 90th percentile for more than five consecutive days. According to this definition, the current Gulf of Maine heatwave started on July 20 and lasted more than a month. However, this statistic downplays what’s been going on this year; only 40 days in 2018 did not reach heatwave levels, and you have to go back to early September 2017 before there are 17 consecutive days below the 90th percentile.
The Gulf of Maine’s rapid warming is related to its position on the planet, receiving cold water from Canada (and ultimately, the Arctic) that meet with warm waters from the south. A slight change in currents can mean a big difference in temperatures, and this region is experiencing more than a slight change.
Global warming is causing the glaciers in Greenland to melt. As this relatively fresh water dumps into the North Atlantic, disrupting circulation, pushing more warm water into the Gulf of Maine.