Ocean Extinction an Destruction


"Ninety-nine percent of all the species that ever lived are now extinct. The modern flora and fauna are composed of survivors that somehow managed to dodge and weave through all the radiations and extinctions of geological hitory."1

Ocean Warming and Rising Sea Levels
The warming of the oceans as a result of global warming may seem to be a temporary bonus to the holidaying tourist, but to fragile, keystone species it is the potential cause for extinction. For example, the Casin's Auklet failed to reproduce in its largest breeding ground2 in 2005 and in 2006. The cause of this failure was warmer oceans which have caused the bird's food to leave the area of the breeding ground.

Ocean warming has a significant effect at the poles. For thirty years, the melt rate was around 8% per decade, although in 2005 and 2006 it became evident that the melt rate has now accelerated sharply - the combined loss in these two years nearing the total loss for the entire previous decade. There is now great concern that the Arctic ice cap is in a final decline, having gone beyond a crucial tipping point. Whereas scientific estimates a few years ago suggested that the summer Arctic could be ice-free within a century, newer estimates place it as likely within only a few decades. There are even some studies that suggest that it could be ice-free during the 2030s, that is, in around twenty years.3 This has severe consequences for a number of reasons. The first is that the ice acts, in effect, like a mirror, shining solar radiation back out into space. The less ice, the more the solar radiation is absorbed by the seas, leading to greater warming.4 "Fresh snow reflects the most light (80-90 percent), but all forms of ice and snow reflect far more sunlight than does water (5-10 percent)."5 Few people expect the Arctic to lose its winter ice, although the fact that we are now contemplating an ice-free summer in the Arctic is very significant, since the Arctic has not been ice-free for over 800 000 years. Yet the likelihood of an ice-free Arctic summer is evidently growing - the September coverage (the month when it is at a minimum) is now 20% less than what it was thirty years ago. Even the winter ice-pack is shrinking at the rate of 4% per decade.6 In 2007, parts of the Arctic experienced an unprecedented heat-wave, with one research station in the Canadian High Arctic recording temperatures above 20C, about 15C higher than the long-term average.7

It should be noted that it is not just the Arctic and Antarctic that are a matter of concern in terms of ice loss. The Greenland ice pack is now experiencing "glacial earthquakes," caused by the movement of massive chunks of ice (around a mile thick and many miles in area), at a much greater frequency than ever before - between 1993 and 2002 there were between six and fifteen such earthquakes, whereas by 2005 this had reached thirty-two.8 Scientists are keeping a firm eye on the Greenland icepack, for were it to melt fully the resulting sea-level rise would be catastrophic in terms of loss of human life (bearing in mind how many people live within a few miles of low-lying coastline). Noting the rapid collapse of the Larsen B ice-shelf in Antarctica in February 2002, and the signs pointing to the possible collapse of Greenland and West Antarctica, Dr. James Hanson, director of NASA's Goddard Institute and arguably the world's foremost authority on climate change, thinks that we have only a decade or so to avert a rise in the oceans of eighty feet."9 Unfortunately, a new study by NASA has confirmed that the surface temperature of Greenland's ice sheet is rising, and that this is leading to substantial loss of ice below.10 While the IPCC estimated that sea level rise this century may reach 20-60cm because of glacial melting, others are suggesting a figure closer to two metres based on recent observations.11

Ocean warming also affects sea levels in another way more obvious than melting ice. When something is heated, it expands, and the same thermal expansion applies to the oceans, and is indeed expected to be the cause of somewhere between 10cm and 43cm rise in global sea levels this century alone, according to the IPCC.12 It should be noted that the total expected sea level rise is greater than this - this figure is simply the amount seas will rise because they have expanded due to heating.

We cannot know by how much the seas will rise, or when this will happen. Some suggest that we have already gone beyond a tipping point, and that we can expect 220 feet of sea level rise over the next few centuries. This would literally be catastrophic for our civilisation. Others suggest smaller figures, perhaps 10 to 20 feet of sea level rise over the next few hundred years, while others suggest a smaller rise over the next few millennia.13 It is clear that whoever turns out to be correct, sea level rise will threaten many hundreds of thousands of human lives over the coming years, as well as many animal species. What we now know is that sea rise is primarily caused by two things - by thermal expansion of the sea, and by "episodes of warming in the waters"14 of the oceans.

Increased meltwater into the oceans is also having a dramatic effect on the ocean salinity, since large amounts of freshwater essentially diluted the saltwater oceans. "Arguably, the largest oceanic change ever measured in the era of modern instruments is in the declining salinity of the subpolar sea bordering the North Atlantic."15 One of the expected results of decreasing salinity or of warmer oceans is that the oceanic circulation patterns may slow down or even shut off.16 This may seem overly dramatic and certainly seemed ridiculous in the film "The Day After Tomorrow," yet there continue to surface new climate models that suggest that the Gulf Stream, as it is commonly known, could shut down fairly rapidly as a result of meltwater in the oceans. "Fairly rapidly," it should be noted, is a reference to decades, not a matter of days as in the aforementioned film. If this were to happen, temperatures across Europe and North America would plunge, while Australia, South America and southern Africa would see dramatic increases in temperature. The reason that the model keeps surfacing is because we are aware that the Gulf Stream has been destabilised in the past - 12 700-11 700 years ago, 8200-7800 years ago, and possibly also 4200-3900 years ago. Added to this the observable decline in ocean salinity, and there is good reason why the Hadley Centre notes that there is a 5% probability of the Gulf Stream shutting down. While this may not at first seem very high, the enormous consequences of it make it very much worth noting.17

Increasing Ocean Acidity
The oceans absorb a phenomenal amount of carbon dioxide from the atmosphere, acting as a sponge that saves us from the full effects of global warming. In fact, around a quarter or all human CO2 emissions - about seven gigatonnes - are absorbed into the sea The problem that is now becoming apparent is that in the process of absorbing the carbon dioxide, some of those emissions are being turned into carbonic acid. The end result of this is that "the oceans today are literally 30 per cent more acid than they were in preindustrial times."18 This poses significant problems to life on Earth. All creatures that rely on calcium carbonate for their skeleton will soon be unable to create those skeletons, and since they are at the foot of the food chain, everything above them will start to be threatened.

To be more exact, the oceans are becoming less alkali. "Average pH values in the top 100m (330ft) of the ocean have decreased from around 8.15 in pre-industrial times to about 8.05 today. That change may seem small, but because pH is measured on a logarithmic scale, every change of one point is equal to a tenfold increase or decrease. A 0.1-point drop in pH translates to a 30% increase in hydrogen ions throughout the upper ocean."19 This net result of this change, which is entirely caused by the absorption of human CO2 emissions, means that the oceans have not been so "acidic" since the last mass extinction. It could be the first human-induced global oceanic pollution crisis, whose consequences "could be even more severe for life overall than global warming."20 If the bottom of the food chain cannot form, then the creatures that currently eat them will collapse, as will all others above them. The decrease in pH of the oceans is therefore a matter of grave concern.

The Corals
It is now recognised that coral reefs are severely threatened, although to what extent is still uncertain. In some years, reefs suffer greatly, for example in 1998, 42% of the Great Barrier Reef was bleached, and in 2002, 60% of the Great Barrier Reef suffered as a result of a huge pool of warm water. It is important to note that where cool patches of water remained, the coral was undamaged.21 If global warming continues, it is safe to assume that corals will suffer significantly, or may even collapse. "If oceans become significantly warmer, they may start to release more carbon than they absorb.... Ocean chemistry is changing a hundred times more rapidly than it has done in the past 100,000 years, and acidity may reach levels that have not occurred for tens of millions of years. The dissolved carbon dioxide, carbonic acid, is corrosive to calcium carbonate shells and exoskeletons. Even low projections for future carbon dioxide emissions indicate that corals could be rare on tropical and subtropical reefs by 2050."22

In 2002, an article in Science by seventeen leading coral reef experts demonstrated how, based on projected human emissions, most of the world's reefs will be massively damaged by 2050. Later the same year, fifteen reef experts demonstrated that "a further rise of 1C (1.8F) in global temperature would see 82 percent of the reef bleached; a 2C (3.6F) increase 97 percent, and a 3C (5.4F) "total devastation."23 The coral reefs are clearly particularly susceptible to climate change, indeed during the El Nio event of 1992-3, three coral species from the eastern Pacific became extinct.24 It is assumed that coral reefs will survive climate change in some form or other, although it is similarly evident that the number of species, and the extent of coral reefs, will be enormously reduced.

Coral reefs are important for us in two distinct ways. Firstly, one in four sea creatures spends some of their life cycle in a coral reef. Secondly, there are a few island nations whose very existence depends on the protection provided their low-lying countries by the reefs.25

The Poles - Above Sea Level
The poles are particularly susceptible to climate change and therefore scientists observe them carefully. It was with great trepidation that at the end of 2004, it became evident that Antarctic hair grass (Deschampsia Antarctica), which previously was a very marginal species had started flourishing, and where once there was snow, there were now practically meadows.26

But it is not the Arctic and Antarctic flora that is of great interest, but the fauna. While Al Gore's important film "An Inconvenient Truth" was criticised for suggesting the melting polar ice has led to polar bears drowning, this is now reported by the Inuit, who have also noticed that polar bears are starving so much that they are turning to cannibalism in order to survive.27 This well-documented starvation has arisen because the summer fast is now a month longer than previously. It is also noted that the average birthweight of cubs dropped 15% from 1981 to 1998 and that (according to WWF estimates) if this starvation continues, females may become too thin to reproduce by the year 2012."28 Similar concerns are expressed over penguin populations - "the emperor penguin population is half what it was thirty years ago, while the number of Adelie penguins has declined by 70 percent."29 The World Wildlife Fund for Nature says that four species of penguin are now directly threatened by climate change - the gentoo, chinstrap, adelie and emperor.30 So too, the ivory gull has declined by 90% in Canada in the last twenty years alone, and looks unlikely to survive.31

Climate change sometimes leads to some creatures flourishing, for example the spruce bark beetle in Southern Alaska. This creature is normally controlled by two successive hard winters, but because of the increased winter temperatures in recent years, the spruce bark beetle has now killed 40 million trees in southern Alaska. Not only does increased winter temperature lead to less beetles being killed off, but the spruce budworm which also threatens the trees lays more eggs at higher temperatures too.32

The change from snow to rain is also having a pronounced effect in the Artic - autumn rain now freezes over food for the Peary Caribou, leading to a population crash from 26,000 in 1961 to 1,000 in 1997.33 Similarly the ringed seal now is struggling to breed since not enough snow is falling for them to create their snow-covered dens. Harp seals in the Gulf of St. Lawrence are experiencing similar difficulties - if there is no ice, they cannot raise their pups, as is now happening with disturbing regularity (1967, 1981, 2000, 2001, and 2002). The ivory gull has declined by 90% in Canada in the last twenty years alone, and looks unlikely to survive.

The Poles - Below Sea Level
It is becoming increasingly evident that an alarming change is developing in the oceans, based particularly, but not exclusively, around the polar regions. Below the frozen ice, krill - tiny creatures that form the basic diet of penguins, seals and whales - thrive. After an extensive survey in the Southern Ocean, it is now known that while krill numbers were stable between 1926 and 1939, from 1976 to 2003 they suffered a sharp decline of nearly 40% every decade. Having noted the crash in population, the cause needed to be identified, and it quickly became clear that the reduction in krill was so closely in tandem with reduction in sea ice that climate change is the indisputable cause.

As noted earlier, when one species collapses, another often fills the niche, and in this case the niche is being filled by salps, which is problematic because they are so devoid of nutrients that the creatures who lived on krill would get no benefit from consuming salps instead.34 The outcome of all this is clear. The crash in the population of krill will certainly result in dramatic losses amongst penguins, seals and whales. It is well documented that in the last fifty years human beings have taken 90% of the fish stocks from the seas. Now we are coming to realise that our emissions may have caused so much extra damage to the ocean food-chain that many species may become extinct, and the food-chain is likely to never fully recover.


1. Wilson (1992), p. 344
2. Flannery (2005), p. 318
3. Henson (2006), p. 73
4. Flannery (2005), p. 316
5. Flannery (2005), p. 15
6. Henson (2006), p. 72
7. The Independent newspaper, Oct 3rd 2007
8. Flannery (2005), p. 318
9. Flannery (2005), p. 318
10. The Ecologist, Vol 38, Issue 3, April 2008, p. 11
11. The Independent newspaper, Sep 8th 2007, p. 34
12. Flannery (2005), p. 146
13. Flannery (2005), p. 148-150
14. National Geographic, June 2007, p. 69
15. Daniel Glick, National Geographic, q. Flannery (2005), p. 189
16. Dow and Downing, (2007), p. 33
17. Flannery (2005), p. 189-96
18. Thomas Lovejoy, Planet Earth (1996), p. 127
19. Henson (2006), p. 116-7
20. Flannery (2005), p. 319
21. Flannery (2005), p. 108-9
22. Dow and Downing, (2007), p. 48
23. Flannery (2005), p. 109
24. Wilson (1992), p. 271
25. Flannery (2005), p. 105
26. Flannery (2005), p. 95-7
27. Flannery (2005), p. 318
28. Henson (2006), p. 77
29. Flannery (2005), p. 98
30. The Independent newspaper, Dec 11th 2007, p. 24
31. Flannery (2005), p. 102
32. Flannery (2005), p. 98
33. Flannery (2005), p. 100
34. Flannery (2005), p. 95-7