The Great Barrier Reef Marine Park was established in 1975 and originally included 5.6% of its area in no-take zones. That was expanded to over 33% in 2004. Photo by Ove Hoegh-Guldberg/University of Queensland
This year's World Oceans Day has the theme "one ocean, one climate, one future." This couldn't be a more timely focus. With so much attention on the climate change impacts we can see from land, the drastic changes occurring beneath the waves often go unnoticed. But the Great Barrier Reef is unraveling a tale we need to listen to. Coral Reefs at Risk
As a marine biologist and avid diver, I've been fortunate to log thousands of hours underwater to study Australia's Great Barrier Reef. And when considering climate change and the oceans, coral reefs are like the canary in the coal mine.
Warmer water temperatures and ocean acidification — both caused by more carbon dioxide in the atmosphere and seawater — are killing coral ecosystems at a much faster rate than we expected. We've already lost 40 to 50 percent of the coral in the Western Pacific and South-East Asian reefs. The world's coral could die within our lifetime, and with them, thousands of species of fish and molluscs living there -- the daily protein for an estimated 100 million people on tropical coasts.
Coral bleaching caused by warmer than normal sea temperatures. Scientists have recently shown that coral reefs are protected bounce back three times faster than if they are being impacted by overfishing. Photo by Ove Hoegh-Guldberg/University of Queensland
Getting Results with Conservation Efforts
The oceans are like the Earth's life-support system, providing food, regulating our atmosphere and shaping our coastal environments. We can't afford to ignore the threats the oceans face.
For one, we can help our oceans withstand the changes already happening. One way to do this is to protect the biodiversity and balance of ecosystems by setting aside key areas for conservation in marine protected areas.
Australia tried this approach more than 30 years ago, and the results are here for everyone to see: more and bigger fish. Australian fishermen will tell you that it was tough for the first few years, since fishing is limited inside these reserves. But now that fish are repopulating areas outside the reserves, the local fishing and tourism industries are big supporters. We all benefit from a healthier ocean.
Marine protected areas can also make ecosystems more resilient to storms and other environmental stresses and -- amazingly -- the impacts of climate change.
I was part of a team of scientists that showed that bleached coral reefs -- damaged because of warmer waters -- recover three times faster in areas with healthy populations of parrotfish, which eat seaweed and prevent it from overwhelming sick and dying coral.
This is just one small example to illustrate the power, and importance, of marine protected areas. The web of ocean life has many connections and dependencies. We can't begin to understand all of them, but we can use what we do know to act now and prepare for the future.
And we know this: Given the chance, nature can bounce back surprisingly quickly.
Coral reefs build extensive ramparts made of calcium carbonate which act as barriers to the power of oceanic waves. Here are coral reefs photographed from the air surrounding Heron Island on the southern Great Barrier Reef. Photo by Ove Hoegh-Guldberg/University of Queensland
Australia and California as Examples of Coral Conservation Efforts
That's why Australia recently increased the percentage of the Great Barrier Reef designated as marine protected areas to nearly 35 percent, from just 5 percent five years ago. Australia's 300 marine reserves cover a total area that is larger than the state of California, helping to restore declining fisheries.
And speaking of California, the famously green state is taking a leading role in addressing both climate change and marine health issues. California is currently in the process of protecting its renowned coastal waters with a network of marine protected areas through the Marine Life Protection Act. With unique and threatened marine habitats set aside for the future, the state's fish and wildlife are more likely to withstand assaults over time, like fishing pressure and climate change.
Of course, marine conservation alone is not sufficient to avert a crisis in our oceans. We must commit, as a global community, to reducing greenhouse gas emissions as well. It will take a concerted effort for our planet, and our oceans, to recover.
But we are not too late. By supporting marine protected areas, we can make a real difference this World Oceans Day and many days to come.
Professor Ove Hoegh-Guldberg is Director of the Centre for Marine Studies at University of Queensland where he is Queensland's Smart State Premier's Fellow, Director of the Stanford Australia overseas program, reviewing editor at Science Magazine and Deputy Director of the Australian Research Council Centre for Excellence for Coral Reef Studies.
More on Coral Reefs
Focus Earth: May 15, 2009: Coral Reefs in Trouble and Melting Tundra
6 Steps to Saving the World's Coral Reefs
Coral Reef Loss in Southeast Asia to Reduce Food Supplies 80%: Strong International Action Needed