Atlantic waters reached record-breaking high temperatures this summer, which conservation experts say could be detrimental to marine life and ocean circulation down the line.
And they are warming the impacts of these temperatures on ocean systems and biodiversity can be devastating.
The North Atlantic has been hit particularly hard by heat waves, including off the eastern coast of Atlantic Canada. According to the Copernicus Climate Change Service (CCCS), daily anomalies in the region reached an unprecedented six to eight degrees Celsius (C) or higher in some areas during the second half of July.
The average anomaly for July as a whole was 1.05 C, which the CCCS says is an “exceptional” anomaly for the time of year.
A temperature anomaly is the departure value from a long-term average reference temperature. A positive anomaly over zero indicates that the observed temperature was warmer than the reference value.
Global waters as a whole have also been experiencing long periods of unusually high sea surface temperatures since April. The highest temperature recorded by CCCS this year was 20.96 C on July 31 — a slight increase from the previous record of 20.95 C in March 2016.
The Fisheries Council of Canada says they expect to see consequences of warming waters arise in the coming years.
“We are seeing some climate impacts now and they will intensify and more generally turn negative in the decades to come. Ultimately, that could impact jobs in the sector,” the council said in an email statement to Global News.
John Driscoll, fisheries and science policy analyst at the David Suzuki Foundation, says his biggest concern is the cascading consequences on the food web.
“I think for the immediate marine ecosystem, the marine species that Canadians are so familiar with, the big concern is just alteration and disruption of food webs. And those are infamously difficult to predict,” Driscoll told Global News.
The removal of a single organism in a food web can have drastic effects on the entire ecosystem. A lack of a predator’s typical food source leads to starvation and extinction.
A food web disruption caused by heat waves has been observed before.
The humpback whale population in Southeast Alaska faced a serious disruption during a marine heatwave between 2014 and 2016. The whales moved into areas they wouldn’t typically be found, and both birth rates and survival rates plummeted, according to the U.S. National Parks Service.
“It’s easy for us as land-based animals that are used to extreme fluctuations in heat to underestimate the importance of changes in temperature to marine species,” Driscoll said.
But for many predators, different parts of their life cycle are timed with specific events in the ecosystem such as plankton availability. If the timing changes due to the heat, or the prey isn’t where it needs to be, or is replaced by something slightly different, then predators may not have what they need to survive.
“This cascades through the food web,” Driscoll says.
“When you have a lack of prey in one place or time, then the species that eat them may be malnourished and not survive as well and that can filter up to your larger animals like whales.”
Driscoll says that while these consequences will likely take months to play out, unceasing rising sea temperatures will make efforts to stall food web disruption more difficult.
James Snider, leader of the World Wildlife Fund (WWF) – Canada’s science, knowledge and innovation team, says the high sea temperatures are “eye opening” in terms of impact.
“Whether it’s large migratory species like leatherback sea turtles (or) North Atlantic right whales… these species are incredibly sensitive to a change in climate and the changes in sea temperature,” Snider told Global News.
Snider says he is particularly concerned about narwhals, a whale species, as they are highly dependent on sea ice and other sea ice dependent species.
Ninety per cent of the world’s narwhals can be found in Canadian waters in the summer.
“The changes in sea temperature that we’re seeing I think are just an indication that the extent to which this is occurring, and the effects of climate change, are real. They’re happening right now,” he said.
Snider says the current sea temperatures are a strong reminder of the need for urgent action and ambitious policies to make sure greenhouse gas emissions are being reduced in Canada and around the world.
The 15th Conference of Parties to the UN Convention on Biological Diversity, or COP15, adopted the “Kunming-Montreal Global Biodiversity Framework” (GBF) in 2022, including four goals and 23 targets for achievement by 2030.
One target includes protecting and conserving 30 per cent of Earth’s lands and waters by 2030.
“There is a very important role of our protected conservatories to provide safe and secure habitat for many of these species and providing refugia in some cases for a changing climate,” Snider said.
“I think (there’s also) the opportunity for modernizing our approach to protected areas, including in the marine environment, seeing that there are inherently dynamic places that we’ll need to respond to the changes in distribution of marine species, as they in turn respond to a change in climate,” he said.
The CCCS says rising sea surface temperatures can also lead to socio-economic impacts due to effects on fisheries, aquaculture, tourism and other industries.
Rising sea temperatures can also play a part in how hurricanes form.
Scientists at the National Oceanic and Atmospheric Association’s (NOAA) Prediction Center announced Thursday that they are increasing the likelihood of an above-normal Atlantic hurricane season to 60 per cent.
“Forecasters believe that current ocean and atmospheric conditions, such as record-warm Atlantic sea surface temperatures, are likely to counterbalance the usually limiting atmospheric conditions associated with the ongoing El Nino event,” a NOAA press release says.
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