What we do to the oceans we do to ourselves

Here’s your weekly Science Matters column by David Suzuki with Faisal Moola.

What we do to the oceans we do to ourselves

Our planet with its atmosphere is an exquisitely interconnected system of ocean, air, and land. Water flows through all of it and keeps it – and us – alive. Water continually cycles above, on, and below the Earth’s surface, driven by the sun’s energy. It evaporates from the seas, transpires from plants and soil, flows from glaciers and aquifers, and falls as rain or snow. It covers 71 per cent of the Earth’s surface. It can be liquid, gas, or solid. And it regulates the planet’s temperature.

Part of the way water maintains a fairly steady surface temperature on Earth is by mixing with carbon dioxide to create a heat-trapping blanket in the atmosphere. But when we pump too much carbon dioxide and other pollutants into the air and water, it upsets the balance.

Even though our oceans and atmosphere are vital to all life, we often treat them as waste-disposal sites. We are putting more carbon dioxide into the atmosphere than the plants on land and in the oceans can reabsorb and process, and so it builds up, trapping more heat and causing the planet’s long-term temperature to rise.

Many of consequences have been widely reported, but global warming’s effect on the oceans hasn’t garnered the attention it deserves. As well as raising the temperature of the oceans, increased carbon dioxide concentrations cause acidification. The oceans absorb and store carbon, which makes them a good hedge against climate change. But when too much carbon ends up in the ocean, the ocean’s pH levels fall and the water becomes more acidic.

Scientists warn that this could have a significant impact on coral reefs, perhaps even wiping them out entirely. If the reefs disappear, half of all life in the oceans will go with them. The process that affects corals – lower pH levels hindering their ability to calcify their skeletons – will also reduce the ability of phytoplankton to form calcium carbonate in their shells and skeletons. This, in turn, will reduce the ocean’s ability to absorb and store carbon, leading to increased global warming.

Despite the warnings from scientists, ocean acidification hasn’t been a big part of climate-change negotiations. That may change. In May, delegates from 76 countries at the World Oceans Conference in Manado, Indonesia – many of them island or developing nations that will feel the greatest impact of ocean acidification – drafted a resolution to put the issue on the agenda at the international climate negotiations in Copenhagen, Denmark, in December.

Let’s hope they succeed in waking up the world to this serious issue. We can’t continue to ignore the state of our oceans. Of course, acidification – caused mainly by what we put into the air – is only one problem we’ve created for our oceans. We are also dumping a lot of crap (often literally) into our seas.

One of the most sickening images is of the giant plastic islands swirling in five ocean vortexes. One in the North Pacific is estimated to be larger than Quebec. Now a group of scientists and conservationists is planning to visit the vortex in an effort to figure out how to clean it up.

According to the United Nations Environment Programme, 13,000 pieces of plastic are floating in each square kilometre of ocean, and much of it accumulates in the five large swirling ocean gyres.

Marine animals eat the plastic as it breaks down, and contaminants work their way up the food chain, all the way to humans.

It offers hope to see the scientists looking for answers to this problem, and it’s good to see nations coming together in an attempt to address ocean acidification. But we must all do more to prevent these kinds of problems from occurring in the first place. We can do this by reducing our waste and emissions and by encouraging governments to show more leadership in protecting the Earth and oceans that cover most of its surface.

The oceans are where life is thought to have originated, as is indicated by the saltiness of our blood. The oceans flow through our veins and continue to give us life. Half of the oxygen we breathe comes from the oceans. What we do to the oceans we do to ourselves. It’s something to keep in mind as we celebrate World Oceans Day on June 8. The theme this year is "one ocean, one climate, one future."

Science Matters has been running weekly since 1999. To read past columns, please visit www.davidsuzuki.org/science_matters/.