Our oceans are hotter than ever. Scientists say they worry about what that means for our future

Our planet is changing. So is our journalism. This story is part of Our Changing Planet, a CBC News initiative to show and explain the effects of climate change and what's being done about it.

Amid another record warm year for the planet, one of the most dramatic and alarming changes occurred in our oceans, according to the National Oceanic and Atmospheric Administration (NOAA).  

They are the warmest they've been in recorded history.

In fact, the ocean heat has been topping its own record annually for the past seven years, with last year's record set despite the absence of El Nino — a warming in part of the Pacific Ocean that tends to drive up global temperatures.

While many Canadians — most of whom are land-locked — may not be focused on the state of our world's oceans, people across the globe will be affected by the changes happening in them: species of marine life moving out of their typical regions and into others, creating an imbalance in aquatic life; a rise in sea levels; warmer waters that can add fuel to already powerful hurricanes and changes in our food webs. 

Our oceans are in a "new normal," concluded a study published in the journal PLOS Climate this month that found 2014 was the first year the world's oceans exceeded the 50-per-cent threshold of extreme heat.

"We need to understand that climate change is not really not just a future scenario," said Kisei Tanaka, a marine biologist with NOAA and lead author of the study. "It's something that's happening as we speak. And it has been happening for some time."

These changes, mostly seen in the form of marine heat waves — think of what happened off the coast of B.C. during last summer's heat wave where a billion marine creatures were killed — aren't spread out uniformly across the world's oceans, but are more pronounced in parts of the North Atlantic and the Indian Ocean. 

However, they are increasing in frequency — and are already taking their toll on marine life.

As is typical with climate change, it's the people in the north who are seeing the most rapid alterations to their way of life.

"What you're going to see over time is that parts of the Arctic Ocean will begin to look like Pacific and Atlantic oceans and the species, the ecosystems that thrive here, you're going to see their numbers decrease," said Hilu Tagoona, a senior Arctic advisor for Oceans North, a charitable organization that supports marine conservation together with Indigenous and coastal communities.

"And that's already being seen. Over the last 25 years, the species that typically thrive here, the numbers are going down."

Our oceans store about 90 per cent of our planet's heat. But that energy won't stay trapped forever. And when it is released over time, it means our atmosphere will warm even more.

Tim Boyer, an oceanographer with NOAA's National Centers for Environmental Information, said it's hard to quantify just how much a much a difference it would make if our oceans released their heat energy.