Almost Half of the World's Ocean Life Has Died Off Since 1970

The oceans are a massive expanse of salty water that sustain our planet. They generate half of Earth's oxygen and suck up harmful CO2 created by burning fossil fuels. But over the decades, a lethal mix of overfishing, pollution, intense ocean acidification, and climate change has increasingly endangered the ecosystems and coastal communities that they sustain.

According to the World Wide Fund for Nature's 2015 Living Blue Planet report, since 1970, Earth has lost a whopping 49 percent of global marine animal species. For their investigation, researchers tracked 5,829 populations of 1,234 mammal, bird, reptile and fish species, making this study twice as large as a previous one published by the WWF in 2014. That study found that Earth's population of wild animals had dropped by 52 percent since 1970.

The 2015 report states that climate change, overfishing, and pollution are the main culprits behind this rapid decline in marine populations.

"Climate change is already having an impact on habitats like coral reefs, and this is a major concern for the future," Louise McRae, the study's lead researcher from the Zoological Society in London, told me over the phone. "If this continues we'll have lost our functioning coral reef by 2050."

With three billion people depending on fish stocks as their main source of protein, and over 850 million people benefiting from the economic, social, and cultural services provided by coral reefs, Earth stands to lose a lot if this rapid-fire decline in marine populations continues.

According to the 39-page report, the ocean generates "economic benefits worth at least $2.5 trillion per year." However, at present, "only 3.4 percent of the ocean is protected, and only part of this is effectively managed."

"Increasing marine protected area coverage to 30 percent could generate up to $920 billion between 2015 to 2050," the researchers write.

"The positive news is that this is reversible—we can actually do something about these population declines," said McRae. "On the individual level, people can make an individual choice to buy only sustainably sourced fish."

"But it really does need some high level action as well […] a good strong global agreement on climate change will certainly ensure the protection of coral reefs in the future," she added, saying that debates of such kind should feature prominently at the Climate Change conference, taking place later this year.

Earth is undergoing its sixth mass extinction event, and investigative documentaries such as The End of the Linehave already found that corporate greed, consumer ignorance, and government complacencyare the driving forces behind our depleting fish stocks and marine species decline. With such sobering facts and figures at our fingertips, learning to eat seafood sustainably, and pushing our governments to take further action increasingly seems a top priority, if we want to keep our oceans healthy.