Why Hotter Oceans Are Another Canary in the Climate Coal Mine

Add it to the list of indicators that we are living in a world remade by fossil fuels.

Last year, headlines reported that in 2021, oceans were the hottest ever, on average. For the third year in a row. Now, a new study shows that 2022 set a new benchmark, with the hottest oceans on record, as measured by ocean heat content.

For decades, oceans have absorbed much of the excess heat energy trapped in the atmosphere, thanks to rising levels of greenhouse gas emissions from fossil fuels and other sources. As much as 90% of the extra heat in fact, according to NASA.

The latest research shows that global warming emissions aren't just making the oceans hotter, but also changing oceans' salinity and stratification. The study finds the ocean's salinity-contrast index is also the highest level on record, which implies that salty water (oceans) is getting saltier and fresh water is getting fresher.

The big-picture takeaway here is that warming is changing the Earth's entire hydrological system.

More Heat, More Storms, More Problems

The extra heat held in the oceans acts as a catalyst for a host of climate impacts. As meteorologist and Climate Reality Vice President of Science and Solutions Ryan Towell notes, "We know that warmer oceans can produce wetter and stronger storm systems. We also know that it’s a contributor to rapid strengthening of storms."

The danger goes beyond storms, touching the complex life systems that call the oceans home. As Towell explains, "Warming oceans impact ecosystems and organisms. For instance, we’ve seen the devastation caused by coral bleaching events in the Great Barrier Reef and beyond. And changes in species migration patterns."

In addition, ocean warming can lead to weaker ocean currents, which has big implications for weather patterns and pattern shifts. All of which to say, the change that begins in the ocean won't stay in the ocean and could transform what we think of as normal weather all across the planet.

Or to put it another way, more and more hot water is going to put us into more and more hot water in the years ahead.

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