According to Scientific American and other publications, U.S. scientists from various universities, NGOs, and government agencies have built a world map of the human damages to the oceans. They've overlayed maps of 17 different activities such as fishing, climate change and pollution to produce this world atlas. They've concluded that about 41% of the world's oceans are heavily affected by human activities. Not surprisingly, the areas which remain relatively little affected are near the poles. Now, the researchers hope that their maps will contribute to global efforts to allocate conservation resources. But read more...
You can see above this map which shows how human activities have already impacted the oceans, and where the damages are the most important-- in dark brown. (Credit: Ben Halpern, National Center for Ecological Analysis and Synthesis at the University of California at Santa Barbara) Here is a link to a larger version of this map. And here is a link where you could learn how this map was created. It even includes a short movie.
Here are some excerpts from the Scientific American article. "Marine ecologist Ben Halpern of the University of California, Santa Barbara's National Center for Ecological Analysis and Synthesis and an international team of colleagues first listed 17 ways humans affect the oceans and then mapped each of them. By overlaying each impact on top of one another, the ecologists created a 'current state of affairs for the oceans,' Halpern says. 'I was really surprised that there is no single spot on the planet that isn't being affected by at least one of these factors.'"
Here is another quote from Halpern. "Aquaculture, recreational fishing, sediment input from rivers that are being blocked by dams, atmospheric pollution—we know these are problems or potential problems and we wanted to include them but we just couldn't find the data. Our results are almost certainly conservative. [...] The deep water is such a vast, relatively unexplored area, we just don't know what kinds of impacts we're having on those ecosystems. We spend trillions of dollars going to the moon and we don't really know what's going on in our own oceans yet."
In this news release, the U.S. National Science Foundation (NSF) describes the four-step process used to create the map shown above. "First, the scientists developed techniques to quantify and compare how different human activities affect each marine ecosystem. For example, fertilizer runoff has been shown to have a large effect on coral reefs but a much smaller one on kelp forests. Second, the researchers gathered and processed global data on the distributions of marine ecosystems and human influences. Then the scientists combined data from the first and second steps to determine 'human impact scores' for each location in the world. Finally, using global estimates of the condition of marine ecosystems from previous studies, the researchers were able to ground-truth their impact scores."
Finally, for more information, this research work has been published in Science under the title "A Global Map of Human Impact on Marine Ecosystems" (Volume 319, Number 5865, Pages 948-952, February 15, 2008). Here is a link to the abstract. "The management and conservation of the world's oceans require synthesis of spatial data on the distribution and intensity of human activities and the overlap of their impacts on marine ecosystems. We developed an ecosystem-specific, multiscale spatial model to synthesize 17 global data sets of anthropogenic drivers of ecological change for 20 marine ecosystems. Our analysis indicates that no area is unaffected by human influence and that a large fraction (41%) is strongly affected by multiple drivers. However, large areas of relatively little human impact remain, particularly near the poles. The analytical process and resulting maps provide flexible tools for regional and global efforts to allocate conservation resources; to implement ecosystem-based management; and to inform marine spatial planning, education, and basic research."
Sources: David Biello, Scientific American, February 15, 2008; and various websites
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