Human Damage to World Oceans Mapped, 40% “Strongly Impacted”

by Ian O'Neill on February 14, 2008

Science study map of most imapcted oceans on the planet (credit: B. S. Halpern/Telegraph Online)
If we needed any more proof that we as a race are damaging the worlds oceans, for the first time, our impact has been mapped by new study to be published in Science. It makes for uncomfortable viewing. Taking 17 known types of human impact on marine ecosystems, this new research suggests that only 4% of the oceans are relatively untouched, whilst 40% are strongly impacted by human activity. The most impacted marine ecosystems include the North Sea, the South and East China Seas, the Caribbean, the Mediterranean, the Red Sea, the Gulf, the Bering Sea, the East coast of North America and in much of the western Pacific.

The new, high-resolution map of predominantly yellow regions and red dots could be mistaken for a global temperature map. However, this map is the first of its kind, mapping damaging human activity in the worlds oceans. At first glance it is obvious that most of the oceans have been affected in some way by the continued onslaught of human activity, with only the Polar Regions holding some of the most pristine and untouched seas. These are about the only portions of the map where the reach of human activity cannot grasp, but as global warming increases, the protective ice-sheets are likely to reveal more sea for humankind to exploit.

This new research was released today at the AAAS Annual Meeting and will be published in the February 15th issue of Science. The scientists behind this study are attending a special three day seminar on “Managing Threats to Marine Ecosystems”. Although this work highlights the concerns about damage to our oceans, it may also aid future efforts to preserve areas of low human impact and will help us identify the worst affected regions.

Whether one is interested in protecting ocean wilderness, assessing which human activities have the greatest impact, or prioritizing which ecosystem types need management intervention, our results provide a strong framework for doing so.” – Kimberly Selkoe of the National Center for Ecological Analysis and Synthesis (NCEAS) in Santa Barbara, CA and the University of Hawaii.

The map was created by dividing the Earths oceans into a grid of 1km×1km squares. The 17 contributing human factors were identified (including fishing, coastal development, fertiliser runoff and pollution from shipping traffic) and the extent at which each grid-point was influenced by each contributing factor was calculated. An “impact score” was then allocated at each location to rate how 20 different types of ecosystem are affected by each factor. It was found that an astonishingly high 41% of the oceans had medium-high to high impact ratings. 0.5% had very high impact ratings, representing 2.2 million square km (850,000 square miles).

Although these results may seem grim, it is the first chance scientists have had to evaluate the worst affected oceans, and many appear upbeat about managing the oceans better, preserving what is left of our pristine seas.

Our results show that when these and other individual impacts are summed up, the big picture looks much worse than I imagine most people expected. It was certainly a surprise to me. [...] With targeted efforts to protect the chunks of the ocean that remain relatively pristine, we have a good chance of preserving these areas in good condition.” – Ben Halpern, assistant research scientist at the University of California, Santa Barbara, research leader. “

Source: AAAS, Guardian Online


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Hello! My name is Ian O'Neill and I've been writing for the Universe Today since December 2007. I am a solar physics doctor, but my space interests are wide-ranging. Since becoming a science writer I have been drawn to the more extreme astrophysics concepts (like black hole dynamics), high energy physics (getting excited about the LHC!) and general space colonization efforts. I am also heavily involved with the Mars Homestead project (run by the Mars Foundation), an international organization to advance our settlement concepts on Mars. I also run my own space physics blog:, be sure to check it out!

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