快猫短视频

PLANS to rein in global warming by sucking carbon dioxide out of the
atmosphere and storing it in the ocean have been criticised by scientists, who
warn that they may have disastrous consequences for sea life. But despite their
concerns, there appears to be little anyone can do to stop the projects.

Researchers have been toying with the idea of fertilising the ocean with iron
salts. Add iron, the thinking goes, and phytoplankton will bloom, taking
CO₂ from the atmosphere down to the deep ocean when it dies
(快猫短视频, 2 October 1999, p 34).

Now entrepreneur Michael Markels, who kick-started a company called GreenSea
Venture, is planning what he calls the world鈥檚 largest ever ocean experiment.
GreenSea plans to dump iron into 13,000 square kilometres of the Pacific next
year, to absorb up to 2 million tonnes of CO₂ within 20 days. The firm
hopes to make money selling its CO₂ reduction services to governments
seeking 鈥渃arbon credits鈥�.

But environmental scientists claimed last week that the whole strategy is
flawed. Even seeding the ocean with a giant influx of iron for a century would
suck up less than 15 per cent of the CO₂ that human activity generates,
they say. Worse, the resulting plankton bloom reduces oxygen levels in the
water, encouraging bacteria that produce other greenhouse gases, such as methane
and nitrous oxide. 鈥淲e know that when we fertilise we鈥檒l change the food web.
You鈥檒l change the way the ocean functions,鈥� says Sallie Chisholm from MIT.

Despite these fears, Markels is free to continue with his trial. GreenSea
does not need a permit to seed international waters, he says. While dumping at
sea is restricted by the London and Law of the Sea conventions, Markels鈥檚 iron
pellets don鈥檛 count as garbage. They have been made specifically to be thrown
into the ocean and so are legal.

鈥淚t鈥檚 a loophole,鈥� says Andrew Watson of the University of East Anglia in
Norwich, who helped pioneer iron-fertilisation experiments. While he doesn鈥檛
think Markels鈥檚 trial will permanently damage the ocean, he believes 鈥渢he whole
area needs controlling鈥�.

Chisholm argues that the only way to discourage these companies is to stop
them making a profit. She says ocean fertilisation should be disqualified as a
source of carbon credits. Markels admits he would probably stop his trials if
that happened.

Another strategy鈥攍iquefying CO₂ and pumping it directly to the
ocean floor鈥攈as also been criticised. Brad Seibel from the Monterey Bay
Aquarium Research Institute in Moss Landing, California, points out that dumping
all the CO₂ from a single power plant this way would reduce the
pH of the water by 0.1. This increased acidity should be enough to harm
local sea life, he says.

Unlike iron pellets, however, CO₂ is classified as industrial waste
by the London Convention, which prevents it being dumped in international
waters. Rene Coenen, head of the London office for the London Convention, says
it is considering revising the law next year to clear up the legal disparity
between the two methods.