June 19, 2017 — As the president claims that climate change is a “Chinese hoax” and members of Congress deny that it even exists, those of us who live at the ocean’s edge can testify firsthand to its effects. They include bigger storms, accelerated sea-level rise and warmer waters. On the Cape, those are game changers to a way of life. They affect the community’s character, soul, and livelihood, especially in the commercial fishery.
The biggest long-term threat to fishing in the northwest Atlantic is not excessive regulations, national marine monuments, or over-fishing – it’s hot water. Cold water species like the iconic cod, and even lobsters and northern shrimp, have to put up with living conditions so uncomfortable that they may be leaving home and heading north.
A recent issue of the journal “Science” shows that over the last 10 years, temperatures in the Gulf of Maine have increased three times faster than almost all of the Earth’s oceans. The Gulf’s southern boundary edges along Cape Cod Bay. Beginning there, Gulf surface temperatures increased four degrees between 2005 and 2013 and scientists tell us they could go even higher. That spells disaster for the Gulf’s ecosystem.
The world’s oceans absorb most of the heat humans produce, but when we deposit too much heat into the atmosphere and adjacent waters below, sea life pays the price. With nature out of balance, fisheries shift, oceans acidify, and life-sustaining oxygen levels decrease.
Especially alarming is what we are seeing at the lower levels of the food chain. As water temperatures spike, copepods are disappearing. These tiny plankton-like crustaceans anchor the Gulf’s food chain and when they leave, the chain starts to unravel from the bottom up and fish productivity suffers.
Excessive carbon dioxide emissions, one of the major causes of rapid climate change, are sapping the strength of the giant ocean conveyor belt known as the Atlantic Meridional Overturning Circulation — otherwise known as the AMOC. It’s a vital component of the Earth’s climate system, with a northward flow of warm tropical salty water in the upper layers of the Gulf Stream, and a southward flow of colder water in the deeper layers.