Vol 2 N° 4 [October–December 2004]



p 2 - A carbon sink that can no longer cope?

p 6 - Multimillion dollar water project for Iraq
p 7 - A strategic plan for Afghanistan’s universities
p 8 - Two years to assess global agriculture
p 8 - Asian journalists learn to report the science of HIV/AIDS
p 9 - UNESCO and WMO join forces to combat flood damage
p 10 - The ICTP turns 40

p 10 - Osman Benchikh on why the age of renewables has now begun

p 13 - The solar school
p 16 - Who needs maths at a time like this?

p 20 - Diary
p 20 - New releases
p 20 - Governing bodies

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Acid rain, acid ocean

Homo industrialis has only walked the Earth for 200 years but, in that time, he has burnt ever-greater amounts of coal and oil, and churned out vast quantities of concrete. Half the carbon produced by this frenetic industrial activity has seeped into the world’s oceans.

The oceans have become a sink – and a very effective one at that. A study published in Science last July estimates that the oceans have absorbed 118 billion metric tons of carbon dioxide (CO2) over the past two centuries, about one-third of their long-term potential. As a result, the concentration of CO2 in the atmosphere has only increased by 36% over the same period. Without the ocean carbon sink, the atmospheric concentration of CO2 would have been higher today and global warming more severe. We owe the oceans a lot.

But, we ask in the current issue, can the ocean continue to cope with being a vast carbon sink? A symposium organized by UNESCO’s Intergovernmental Oceanographic Commission last May has concluded that we may yet pay a very high price for this service to humanity. The high concentration of CO2 in the oceans is making them more acidic and there are signs that this is beginning to affect marine life.

With fossil fuel-burning on the increase rather than the reverse, things are poised to get worse for corals, pteropod molluscs, some plankton and perhaps even some fish, which may encounter a whole range of ‘health problems’ as the ocean acidifies, including reproductive difficulties and asphyxiation. That would spell catastrophe for the world’s fishing and coastal tourism industries.

As the surface waters become more saturated with carbon, the ocean may also become a less efficient sink. With less carbon being absorbed by the oceans, more would enter the atmosphere. That would accelerate global warming. Most experiments have been conducted in laboratories up until now, so we cannot say for certain at this stage what lies ahead for the marine food chain. But we need to find out. And fast. Hence the resolve of the science meeting last May to fix urgent priorities for studying ex situ, and above all long-term in situ, the effects on marine life of an acidifying habitat.

W. Erdelen
Assistant Director-General for Natural Sciences


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