Environment Forum

Voyage around the Americas sees acidification off Alaska


Scientists aboard the Ocean Watch, a 64-foot yacht on a year-long voyage circling the Americas, are testing the waters as they go. Instruments on the vessel have picked up evidence of ocean acidification, another result of the spewing of carbon dioxide from tailpipes and smokestacks, they say.
Much of  CO2 pollution ends up in the atmosphere, but some is absorbed in the ocean, where it is converted into carbonic acid. The average pH of the word’s oceans is about 8.1 and the lower the reading, the greater the acidity. 
Scientists are concerned that if pH levels keep falling ocean waters could eat away the shells of organisms large and small. That would put the web of ocean life at risk, not to mention be a potential disaster for land-loving seafood lovers
Ocean Watch has picked up readings of 7.88 in the Gulf of Alaska. Michael Reynolds, the scientist taking the measurements, said the preliminary data may show that the Gulf of Alaska is a primary “sink” for atmospheric carbon.
The good news is that readings have returned to normal as the voyage continues off the coast of South America.    

The Ocean Watch has taken other environmental observations, on things like declining ice cover in the Arctic, and it sailed through the Northwest Passage, one of only 100 ships to do so in the last 100 years. A special camera is observing the gaggles of jellyfish the ship encounters. The creatures are among the world’s hardiest, so the scientists want to see what kind of jellyfish are thriving in waters that are acidic or are polluted in other ways and what changes they are undergoing.
“The boat is acting as a spotlight on issues known to scientists and local fisherman, but are not known to the general public,” said David Rockefeller, a philanthropist who is sponsoring the $2 million voyage for Sailors for the Sea. He will climb aboard Ocean Watch later this month off the coast of Patagonia.
The sailors are sharing their observations and concerns with the public at ports along their journey.  
Ellen Lettvin, an education expert at the Pacific Science Center, said the Ocean Watch scientists will analyze the data at the end of the voyage and provide it to the National Oceanic and Atmospheric Administration and other organizations tracking the health of the oceans.

Photo:  David Thoreson

Seas rise — vast amounts of ice melt for every 1 mm gain

It takes the equivalent of a massive chunk of ice of 390 cubic kms (150 cubic miles) to raise world sea levels by one millimetre, according to David Carlson, director of the International Programme Office of the International Polar Year.

As an example, he says that works out as a lump 39 kms long, 10 wide and 1 km thick. Or I reckon it could be a blockbuster ice cube with sides 7.3 kms long — that would smother most of  a large city such as Paris (top left — you can see the Eiffel Tower in the middle).

David’s numbers give an idea of the scale of the thaw under way — seas have been rising at about 3 millimetres a year in recent years in a trend that almost all climate scientists blame on global warming caused by human activities. That’s equivalent to a rate of 30 cms a century.

A view from the North – Alaska’s melting glaciers

exitsign1.jpg Welcome to the front lines of global warming in the United States – the Harding Ice Field in Alaska, the biggest icefield in the United States.
   At the Exit Glacier north of Seward – the only glacier in the Kenai Fjords National Park reachable by foot – the giant cerulean blue ice sheet gives every sign of staying put.
   But one only has to glance at the many signs along the roadway and footpath to the glacier’s edge to mark its retreat  – it hit its peak size in 1815 and has been receding ever since. Signs along a footpath leading to the base of the glacier show just how far it has retreated.
   The glacier lost about 10 feet from its front face over the summer of 2008.
   Since the 1980s, land-based glaciers and ice caps like this one in Alaska have contributed the most to sea level rise than any other source within their category, which includes other land-based glaciers like Tanzania’s Mount Kilimanjaro and the Chacaltaya Glacier near La Paz, Bolivia, said Brenda Ekwurzel, a climate expert with the Union of Concerned Scientists.ailikcrash11.jpg
   Unlike the ice cover around the North Pole or giant floating ice sheets, land-based ice contributes directly to sea-level rises.
   According to a 2007 report by the U.N.’s Intergovernmental Panel on Climate Change, glaciers and ice caps have the potential to raise global sea levels by between .15 meters and .37 meters.
   That pales in comparison to the giant ice sheets in Greenland and Antarctica, which could raise sea levels by 63.9 meters if they fully melted.
   At the Aialik Glacier in the Harding Icefield – reachable by boat or plane, the living nature of the ice was more evident.
   On a visit to the glacier via tourboat on Aug. 15 on a trip hosted by the Knight Center for Environmental Journalism, several chunks of ice broke apart and crashed into Aialik Bay.
   glacier7.jpgThroughout the visit, the ice cracked andgroaned, with a sound like thunder claps that punctuated the still air.