As climate change has gradually heated oceans around the globe, it's also been making ocean waves stronger and more deadly, according to a new study published in Nature Monday.
Upper-ocean waves are driven by local wind patterns, which are driven by temperature differences between different layers of the air. So as we pump greenhouse gases into the atmosphere and heat up the air, we're also strengthening certain wind patterns and weakening others. The net effect on our oceans is stronger winds making stronger waves.
"We show that the global wave power, which is the transport of the energy transferred from the wind into sea-surface motion, has increased globally," the authors wrote.
For people working industries that rely on ocean transportation—such as fishing and global cargo transport—this means that their already-dangerous jobs are going to become even more dangerous over time. Commercial fishing specifically has a mortality rate 32 times higher than the general working US population, and 18 percent of these deaths can be attributed to being struck by waves.
The study found that since waves, on average, have gotten 0.41 percent stronger every year from 1948 to 2008, as measured in kilowatts per meter. This may not sound like a lot, but consider that this is an average. The waves in the Southern Ocean, which surrounds Antarctica, have gotten about 2 percent stronger every year.
It's already incredibly dangerous to travel to Antarctica by sea: heavy-duty ice breakers are required in areas with more sea ice, and an ultra-luxury tourism trend of traveling on cruise ships to the frozen continent has been growing steadily almost every year.
It's often easier and safer to travel to Antarctica by plane, and we'll probably have to rely on that method even more going forward. But that requires constructing more expensive, destructive runways on the frozen landscape. (China is planning to construct a nearly mile-long plane runway for researchers.)
2017 was the warmest year for the global oceans on record, largely because oceans take up 90 percent of the extra heat in the atmosphere that's generated by humans due to our release of greenhouse gases. Oceans also warm more slowly than other global arenas—like forests, deserts, or even the air itself. This means that overall and over time, oceans have a greater capacity get hot and stay hot for a long time. The ways in which we're altering our oceans will persist for years.
It's worth noting that we're also affecting the ocean in places we can't see. Atlantic meridional overturning circulation (AMOC), is a global circulation process that sends cold water to the surface and warm water to the depths of the sea around the globe, which helps regulate salt levels around the globe. Since climate change is heating ocean water everywhere, this process has been weakening, putting all salinity-specialized ocean creatures at risk.
The consequences of climate change go far beyond making our world a little hotter each year. As we emit greenhouse gases, we set off environmental feedback processes to which the ocean is particularly vulnerable.