The study predicts that the maximum rise by the year 2100 is 30cm (Photo : Reuters)
Evidence have shown that sowing the ocean with particles of iron can suck up and store carbon dioxide which may reduce the impact of climate change , according to German researchers.
The study, organized by the Alfred Institute for Polar and Marine Research using geoengineering, has come under attack from fellow scientists and environmentalists. The Guardian reports geoengineering is controversial as critics warn there are unintended environmental side effects in the process.
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"The time has come to differentiate: some geoengineering techniques are more dangerous than others. Doing nothing is probably the worst option," said Prof. Victor Smetacek of the Alfred Institute.
Although probes into ocean fertilization are banned under international law, for scientific purposes, the practice is allowed.
A goal of the study is to take carbon dioxide from the atmosphere and store it deep in the ocean so that it no longer adds to the greenhouse effect. According to the Mother Nature Network, "this would be done by scattering the ocean surface with iron dust, a nutrient for microscope marine vegetation called phytoplankton."
As plants digest the iron, they also take in atmospheric carbon dioxide thanks to natural photosynthesis.
The researching team added iron sulphate next to an Antarctic ocean, where iron levels are extremely low. The addition of the iron prompted an increase of phytoplankton to begin growing within a week. As the phytoplankton began to die after three weeks, they sank towards the ocean floor, taking the carbon they had incorporated with them.
The scientists chose the experiment location carefully, within a "60km-wide self-enclosed eddy" in the ocean that acted as a giant "test tube," according to reports. With the location secured, it was possible to compare what happened within the eddy with control points outside the eddy. After observing for a month, the researchers concluded at least half of the bloom had fallen to depths below 1,000m and that a "substantial portion was likely to have reached the sea floor" at 3,800m.
The scientists conclude in the journal Nature that the carbon is therefore likely to be kept out of the atmosphere for many centuries or longer.
On the ethics of geoengineering, Smetacek told the Guardian, "We could reduce emissions significantly and increase the scope for sequestration on land [by freeing grazing land for forestry] if we managed to convert the global population to vegetarianism. Would that be geoengineering?"
In 2009, Britain's Royal Society conducted their own research into geo-engineering, chaired by Prof. John Shepherd. Their conclusion contradicted the German researches reports, and found that ocean fertilization would not suck up that much carbon dioxide and could be dangerous to the marine biosphere.
"Whilst the new research is an interesting and valuable contribution in this evolving field, it does not address the potential ecological side effects of such a technology in what is a poorly understood field," said Shepherd to AFP.
The environmental non-governmental organization ETC Group campaigned against geoengineering, stating the study, "only focuses on a few narrow aspects and disregards or ignores others. The intended purpose of ocean fertilisation is to significantly disrupt marine ecosystems through drastic changes on phytoplankton, which is the base of the marine food web, so the effects would propagate throughout the ocean in unpredictable ways."