[R-G] No ocean is untainted by the polluting hand of Man

[Anthony Fenton]

 From The Times
February 15, 2008
No ocean is untainted by the polluting hand of Man
Map showing marine damage to the oceans caused directly by humans
[Link to Map: http://extras.timesonline.co.uk/pdfs/marine_map_1.pdf]
Mark Henderson, Science Editor


Almost half of the oceans have been badly damaged by humanity and no  
region has been left untouched, the first global map of Man’s impact  
on marine ecosystems has revealed.

The ambitious project to chart the changing ocean environment shows  
that Man has exacted a much heavier toll on the seas through fishing,  
pollution and climate change than had been thought.

The world map, which was created by dividing the oceans into  
kilometre squares, shows that 41 per cent have been affected strongly  
by 17 human activities, a much higher proportion than expected.

Some of the worst-affected marine areas are found around the British  
Isles. Parts of the North Sea, the Channel and the North Atlantic off  
the Irish and Scottish coasts have all been assessed as suffering  
very high ecological damage.

The map is the first to combine information on how different human  
influences are affecting the oceans. It examined indicators of  
environmental health, including coral reefs, fisheries, kelp forests  
and water quality.

Ben Halpern, of the US National Centre for Ecological Analysis and  
Synthesis (NCEAS), who led the study, said: “This project allows us  
to finally start to see the big picture of how humans are affecting  
the oceans. 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.”

David Garrison, the biological oceanography programme director at the  
US National Science Foundation, which funded the initiative, said:  
“This research is a critically needed synthesis of the impact of  
human activity on ocean ecosystems. The effort is likely to be a  
model for assessing these impacts at local and regional scales.”

The map, which was presented at the annual meeting of the American  
Association for the Advancement of Science in Boston yesterday, was  
produced by drawing up human impact scores for each marine square. A  
paper describing the map has been published in the journal Science.

Each type of human influence fits one of four categories: climate  
change, pollution, fishing and shipping. Climate change has had the  
greatest impact, particularly though rising sea temperatures and its  
effect of acidifying the oceans. The effect of fishing is the next  
most important, especially the damage that has been caused to coral  
reefs from trawling and stock depletions from overfishing.

In many regions the effects of these are combined with pollution,  
particularly run-off of fertilisers from agricultural land and  
invasive alien species that are often introduced in the ballast tanks  
of ships.

“Clearly we can no longer just focus on fishing or coastal wetland  
loss or pollution as if they are separate effects,” said Andrew  
Rosenberg, a professor of natural resources at the University of New  
Hampshire, an indepedent scientist who was not involved with the study.

“These human impacts overlap in space and time and, in far too many  
cases, the magnitude is frighteningly high. The message for  
policymakers seems clear to me: conservation action that cuts across  
the whole set of human impacts is needed now.”

Beyond British waters the regions that are most affected are in the  
South and East China seas, the Caribbean, the East Coast of North  
America, the Mediterranean, the Red Sea, the Gulf, the Bering Sea and  
several parts of the western Pacific. The areas near the poles have  
been affected the least but these regions are at risk of damage  
through global warming.

“Unfortunately as polar ice sheets disappear with a warming global  
climate and human activities spread into these areas there is a great  
risk of rapid degradation of these relatively pristine ecosystems,”  
Carrie Kappel, of NCEAS, a principal investigator on the project, said.

Dr Halpern said that while the picture is grim it could be reversed  
by urgent action. “There is definitely room for hope,” he said. “With  
efforts to protect the chunks of the ocean that remain relatively  
pristine we have a good chance of preserving them.

“My hope is that our results serve as a wake-up call to better manage  
and protect our oceans. Humans will always use the oceans for  
recreation, extraction of resources and commercial activity such as  
shipping. This is a good thing. Our goal is to do this in a  
sustainable way so that our oceans remain in a healthy state and  
continue to provide us with the resources we need and want.”

British scientists welcomed the study but said that the poor scores  
for British waters could reflect better recording of environmental  
problems.

Emma Jackson, of the Marine Biological Association, said: “The  
unsustainable way in which we exploit the goods and services that  
marine eco-systems provide are shown in this paper and, as a nation,  
we should be concerned.

“But we should consider that the UK human impact hotspot, which  
Halpern and colleagues have highlighted, is partly due to the fact  
that we are fairly good at recording our human activities. It is also  
down to a legacy of historical pressures, which we are now beginning  
to do something about by protecting our marine areas.”

Professor John Shepherd, of the National Oceanography Centre in  
Southampton, said: “This is a bold attempt to make a global map of  
human impacts on the ocean. The high impact shown for UK waters is  
probably due to heavy fishing, intensive exploitation of oil and gas  
resources, shipping and tourism. Not all of these lead directly to  
ecosystem damage but there is no doubt that mankind’s impact is  
significant.”

Professor Chris Frid, of the University of Liverpool, said: “As the  
management of human impacts on the environment seeks to be more  
holistic and ecosystem-based it is critical that we have means of  
assessing the sites of human impacts.

“Spatial mapping of the ‘footprint’ of human impacts is a useful way  
of doing this as different impacts — fishing, oil exploration,  
aggregate dredging — can then be superimposed. The results confirm  
the fact that coastal seas close to populous and industrialised areas  
are most impacted.

“The major limitation of this approach is the pseudo-precision of the  
maps. The original scientists did not score the impact of each  
activity in each square but their responses were transferred by the  
authors to these grids and then aggregated.

“The resulting broad patterns will be correct but the detail in terms  
of footprint and intensity will be approximate and must not be used  
as the basis for management decisions, for example on where to allow  
development.”