We are no longer separated by oceans. We are joined by them.

Cape Town, where I currently live, is an area of incredible natural beauty and biodiversity. Right now, it also encapsulates everything that's happening to the world's oceans.In the last 10 years we've seen a 63 percent drop in the number of African penguins along our coastline.We have fights over fishing quotas.A ship ran aground off Blouberg beach three years ago. It still hasn't been removed. It's still spilling oil along the beach, killing sea birds and other marine life. Nearby, the Black River spews plastic pollution into Table Bay.When my father was born the world's population was 1.8 billion. Today we are 7 billion, and we're expected to be 9 billion by 2050.In just two generations we will have increased our number 5 times over.As we approach World Maritime Day on the 27th, it's important to remember just how crucial the world's oceans are for us. The air we breathe, the water we drink, the fish we eat – they all rely on the oceans.But they are not in a good state.Sea ice in the Arctic is now even less than when I swam across the North Pole in 2007. I've swum in all five oceans and I've seen changes in every one of them - changes that have come about because of our actions.It's not too late to restore the health of the oceans. We have it within our power to make a positive difference. But we must change our attitudes.We cannot bully the world's oceans into providing us with more fish, or expect them to absorb all our pollution without having it thrown back at us. Because all ecosystems are interconnected.I remember watching an autopsy of a sea bird caught hundreds of kilometres out in the north Atlantic. A scientist brought the carcass into a meeting of European ministers and opened it up right there. Inside it was full of plastic. Chunks of red, white and green, tangled up in fishing line.That plastic could have come from your town, or from mine. It could have travelled from inland, along a river, to the sea.Our actions have impact thousands of kilometres away.Remember Fukushima? One year later, radiation from the east coast of Japan was detected in tuna caught off the west coast of the United States.The truth is, we are no longer separated by oceans. We are joined by them.Don't turn your back on the world's oceans. Turn towards them. If we all make even one small change in our behaviour, we can make a difference to our oceans. Together, we can create a Blue Future.Photo Credit: Mike Hutchings