An international investigation into the health of the world's oceans has found that rising global temperatures are spreading disease at an unprecedented level, threatening the global food chains, which of course include us.

The findings suggest that our oceans have 'absorbed' 93 percent of the warming effects of climate change, causing them to become sicker and sicker in the process. This could explain why temperature changes haven’t been felt as broadly on land.

"We all know that the oceans sustain this planet. We all know that the oceans provide every second breath we take," said Inger Andersen, director general of the International Union for Conservation of Nature (IUCN), at the World Conservation Congress in Hawaii this week. "And yet, we are making the oceans sick."

The study, conducted by 80 researchers across 12 countries, is a meta-analysis of hundreds of peer-reviewed studies examining the response of marine ecosystems, from microscopic bacteria to large sea mammals, to global warming.

The investigation revealed that our oceans have been 'shielding' us from the devastating effects of warming since at least the 1970s.

Because oceans take up so much surface area on our planet, as radiation from the Sun hits them, the heat is quickly dissipated. In a world without the oceans, much of that heat would have remained, after bouncing off landmasses and getting trapped in the atmosphere - causing the planet to warm much faster than ours is right now.

"By absorbing a disproportionate amount of heat from global warming, and by taking up the rapidly increasing emissions of carbon dioxide, the ocean has shielded the world from even more rapid changes in climate," the report states.

"However, the extent to which it can continue to do so in the near and distant future is far from clear."

The team says that higher ocean temperatures are likely causing sea creatures to migrate about 1.5 times faster than those on land, forcing creatures like jellyfish, seabirds, and plankton to shift towards cooler waters by up to 10 degrees latitude.

They also say that increased heat has caused the oceans to become filled with harmful microbes at an alarming rate, and that cholera-bearing bacteria and toxic algal blooms are becoming more frequent.

This means that water sources might soon become poisonous to ocean life and, of course, the humans that eat them.

"We are no longer the casual observers in the room," said co-lead author Dan Laffoley, from the IUCN. "What we have done is unwittingly put ourselves in the test tube where the experiment is being undertaken."

Besides making food supplies toxic, the team says warming waters have caused coral reefs - regions where up to 25 percent of all marine fish species live - to die off at unprecedented levels, which will also put a strain on the seafood industry.

By 2050, harvests from marine fisheries in South-East Asia are expected to fall by between 10 percent and 30 percent, relative to 1970-2000, and most of the world's coral reef systems will experience annual bleaching problems.

As of right now, only 38 percent of the world's coral reefs live in waters with low enough acidity for them to thrive - down from 98 percent since the 1700s, when ocean acidification was first starting to rise.

And it's not just tropical areas that are under threat.

The report claims that if the ocean's temperature continues to rise like it is today, Arctic environments will take a major hit, as ice-covered areas are expected to disappear, leaving nothing but open water. In this scenario, polar bears are likely to go extinct between 50 and 70 years from now.

The team hopes that their investigation will convince industries to switch to greener technologies, because our oceans are at a breaking point, and they can’t take the brunt of global warming forever.

"Finally, and most critical, is the need to address atmospheric CO2 and achieve rapid and significant reductions in what we emit," the study concludes.

"To do otherwise will be to 'sleepwalk ourselves into a nightmare', where no level of conservation action in the future will be enough to override the impacts in order to save many of the ocean’s species, ecosystems, and benefits we currently rely on and take for granted."

The report was presented at the IUCN’s World Conversation Congress in Hawaii this week. You can read it in full here.