By Bob McDonald, host of the CBC science radio program Quirks & Quarks

Bob McDonald

The world’s largest underwater observatory has officially opened in Victoria and will provide an unblinking eye on the most unexplored realm of our planet. Neptune Canada is an array of scientific instruments laid out over 800 kilometres of ocean floor, running as deep as 2,600 metres. For the next 25 years, we will be able to explore this dark realm and see how the largest environment on our planet is responding to the climate change happening above it.

When you think about it, we know the surface of Mars better than we know the surface of the Earth. Three-quarters of our planet is in total darkness, under tons of pressure and barely above freezing. The largest mountain ranges on Earth are underwater, and while the floor of the ocean has been mapped by sonar, and research submarines have been down to a few locations, most of our planet remains unexplored.

The Neptune array covers a wide range of environments, from near-shore through continental slopes, into the abyss and hot hydrothermal vents. Instruments planted there provide real-time data on the movement of the Earth’s geological plates, underwater landslides and of course, the unusual life forms that call the dark region of the Earth their home.

But perhaps one of the more relevant roles is the long-term monitoring of the ocean’s slow response to climate change. The majority of carbon dioxide that we are pumping into the atmosphere is absorbed by the oceans, and the consequences of that absorption can affect all life on the planet.

When carbon dioxide interacts with seawater, the water becomes more acidic, which is not good for coral reefs or animals that build shells. The acidity prevents the formation of calcium carbonate seashells and can dissolve the calcium in corals. In other words, it eats away at the very bottom of the food chain. So, while over-fishing is scraping life out of the oceans from the top down, acidification is taking it from the bottom up.

Neither scenario bodes well for the future. Ocean acidification is one of the biggest global concerns today, which makes the role of Neptune extremely important.

Discussions about climate change often concentrate on changes in the atmosphere, but changes in the ocean, which happen more slowly, have a more profound effect on planetary systems. The ocean is the great moderator of our climate, a buffer for sudden change. But like a heavy vehicle you try to push out of a snow bank, it takes a lot to get it moving; but once in motion, is hard to stop.

We have been pushing the oceans with excessive carbon dioxide for more than a century. We’ve been heating it up and changing its chemistry, its currents and the life within it. At the same time, we’re depending more and more upon the limited resources of the seas because, as the saying goes in real estate, they’re not making any more land.

The need to cut back on our carbon emissions goes way beyond changes in the atmosphere and the effect those changes will have on planet Earth. With this new telescope into the darkness below, we can really see our world as Planet Ocean.