Issue #1435 11 November 2009
Culture & Life
Oceans at risk
Oceanic waters cover approximately three quarters of the earth’s surface and contain nine tenths of the planet’s water resources and the majority of living beings. The oceans have been and are essential for life and, in fact, are a substantial part of our biosphere, have an influence on our climate, while their conditions have a bearing on our health and well-being.
While the Maldives are world-renowned for their upmarket tourist resorts, the world often forgets they are also home to an indigenous population with a 2,500 year-old culture. With an average land height only 1.5 metres above sea-level it is the country most likely to completely disappear under the sea by the end of the century.
According to a statement released on June 1 this year by 70 scientists from all over the world, including some from Cuba, the rapid increase in carbon dioxide (C02) emissions since the Industrial Revolution in the 19th century has created an increase in ocean acidity that could have profound consequences for marine plants and animals, especially those that need calcium carbonate to grow and survive, as well as other species that depend on the former for food.
The level of acidity that ocean waters have reached in the last 200 years is probably the highest experienced in hundreds of thousands of years, and the situation is becoming even more critical, given that this level is increasing by a rate 100 times faster than in any previous moment.
This situation is directly related to human, especially industrial, activity, which has provoked an enormous increase in atmospheric C02. Part of that carbon dioxide has remained in the atmosphere, where it is one of the principal causes of the increase in the greenhouse effect; another part is established in land plants; and the rest, meanwhile, has been absorbed by the oceans.
According to reliable scientific data, the atmospheric C02 is currently at its highest ever level in at least the last 800,000 years, and very probably in the last 25 million years, which has led and will lead to a significant increase in atmospheric and ocean temperature in the next few decades. At the same time, the ocean has absorbed around 430,000 million tons of atmospheric carbon dioxide (C02), which represents something like one third of all C02 emissions produced by humans.
The major part of international trade and almost 30 percent of oil extractions take place in the marine environment. The value of the world fishing industry is calculated at approximately US$50 billion and its volume is around 90 million tons. Some 36 million people are employed in the fishing and agricultural sector and will lose their work if the current situation continues to worsen.
Over the last 10 years, UN experts have alerted the world to what they consider to be the greatest threat to the world’s oceans: pollution from land-based sources, overfishing, and the destruction of marine habitats. Now this new factor – the growing relative acidity of ocean waters – the reach and consequences of which have only become clear in the last few years, can be added to that complex picture.
The natural absorption of C02 by the world’s oceans does contribute to mitigating the adverse affects on the climate that come from anthropogenic emissions of this greenhouse gas, but the damage produced in marine ecosystems by acidification represent too high a price to sit back and accept this situation, and thus scientists have raised the alert.
Barely four years ago, the Royal Society of London (the UK’s national academy of science) published an exhaustive review of oceanic acidification and its potential consequences. The term “oceanic acidification” was coined by Caldeira and Wickett two years earlier.
There is growing evidence of a varied range of biological effects and marine biochemical processes related to the carbon cycle. In that way, they have now verified impacts, both in the Polar Regions and in tropical areas, attributable to this.
In practical terms, it should be noted that although ocean acidification is a global phenomenon, changes in the chemical makeup of the oceans will present themselves in different ways in each region, meaning that some will be more rapidly affected than others.
For example, it is estimated that the increase in acidity will be more quickly evident in the Bering Sea and in the Eastern Pacific. But it will also produce adverse effects, such as a decrease in the concentration of carbonate ions that are crucial for the structure of coral reefs in tropical oceans like those that encircle the extensive and famous Great Barrier Reef, located between Australia and New Guinea.
According to studies undertaken in the past few years, in the time period following the Industrial Revolution almost all tropical and subtropical areas that had coral reefs were surrounded by water with a composition favourable to coral growth. On the contrary, it is feared that if atmospheric C02 comes to stabilise at 450ppm (parts per million) only a small fraction, around 8 percent, of the tropical and subtropical reefs will remain surrounded by water favourable to their growth. In the case of such concentrations reaching 550ppm, there could be a massive break up of coral reefs globally. For cold water coral reefs, the prospect is not much more promising. The way things are going, by 2110 approximately 70 percent could be surrounded by water unfavourable to their development.
While it is true that some live organisms will benefit as a consequence of changes in ocean conditions, the majority of species will be negatively affected, given that their growth and development in current conditions is the result of a long period of adaptation. Therefore, it is feared that if the current deterioration of ocean chemical conditions is not halted, the damage to marine ecosystems could be very severe.
Thinking about possible methods of mitigation, the potential to correct or reduce the increase in acidity through the massive addition of chemical substances into the oceans would seem extremely improbable, owing to elevated costs and the fact that it is difficult to predict if such substances would, at the same time, have adverse effects on the marine environment.
The only plausible alternative is to minimise as far as possible changes of even greater magnitude and for even greater time periods to the composition of the oceans, by reining in the increase of atmospheric concentrations of C02 through a drastic reduction of the emissions of the said gas from human activity. That is how scientists from all continents see it, and they are demanding effective measures from governments to achieve a no less than 50 percent reduction in C02 emissions – based on volumes emitted in 1990 – by 2050 and further reductions afterwards.
Another United Nations Climate Change Conference (the 15th) is scheduled for December 2009, aimed at reaching an agreement to achieve these necessary reductions. A recent preparatory meeting with secondary organisations took place in June with very unpromising results (if one could call them results).
Only time will tell if the arrogance and greed of the powerful will prevail on this crucial issue or if good sense and rationality will open a way in the socioeconomic ordering of the world. No matter how you look at it, the latter is essential if the oceans are to be saved and, with them, all of humanity.
* The author is president of the Cuban Academy of Sciences.
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