Humans have a lot of ways to measure their health. We take stress tests on our hearts. We check our cholesterol. Heck, we can stick a thermometer under our tongue to see if that chill is just a cold room or something more malicious. But those things only give a snapshot of certain systems; it's hard to measure the big picture.
And if it's hard for us humans, imagine attempting to measure the health of the world's oceans, which cover 71 percent of Earth's surface, and hold 97 percent of the world's water. While we can learn a thing or two by taking the ocean's temperature, we need more robust systems to determine how the ocean's overall health is faring.
The Ocean Health Index is one attempt to do that. The index, a partnership between Conservation International and the National Center for Ecological Analysis & Synthesis (NCEAS) at University of California, Santa Barbara, has a few purposes.
"The Index is a measurement/evaluation tool, a tool to inform and encourage policy and management actions, and a communications tool," Lindsay Mosher, coordinator for the Ocean Health Index, says via email.
The OHI calculates an annual global score for ocean health, as well as individual scores for nations on well they're protecting and stewarding their share of ocean waters. So how does the United States stack up?
Well, could be better. The United States scored a 70 in 2016. The good news is that's super close to the overall 2016 global score of 71. The bad news is that the scale goes to 100, and 70 is a pretty mediocre grade. But let's dive in and learn a little more about how the ocean's health is measured, and why the United States places where it does.
The OHI annually measures 10 goals that range from biodiversity to tourism and recreation. (You can see the full list of goals here or at the bottom of the article.) Note that the OHI is keen to measure not just the ocean, but how well people are using it: That means things like artisanal fishing opportunities, or whether people who need to fish can, are measured alongside conservation efforts.
In some regards, the United States is doing pretty well. On the artisanal fishing opportunities front, it scores a 100. It seems to excel in coastal protection and biodiversity, with both areas scoring 85, but Mosher cautions that the U.S. shouldn't be clapping itself on the back.
"While Biodiversity and Coastal Protection remain the highest scoring goals, reference points for both goals include maintaining coastal habitats at or about their extent in 1980," she says. "So decline of their scores from 100 have occurred in less than four decades. Continuing threats to habitat condition would lower scores further."
But when measuring how sustainably people harvest nonfood products from the ocean, the U.S. gets a measly 44. The U.S. also received a low score of 47 for how many people are employed in a tourism or marine recreation industry.
The United States, with its score of 70, placed 85 in the list of 221 regions. Germany (score of 85) and Australia (score of 80) were the only regions with populations of a million or more to score 80 or higher for ocean health. Howland and Baker islands, two uninhabited U.S. atolls located in the Pacific near the equator, claimed the No. 1 spot on the index, with a score of 91. Globally, the score has fluctuated only one point for the entire five-year study period.
"The score sends a message that the ocean isn't ‘dying' the way many people think, but that people and marine life will fare much better when we use it in more sustainable ways," Mosher says.
So what to take away? Well, the U.S. score does keep dropping from a high of 76, meaning that the country isn't improving the health of its oceans . However, the steady global score is a reminder that the oceans are still thriving habitats and that change — for better or worse — happens slowly.