Extinction of Species

There are so many examples of climate-change-induced destruction and extinction, that the following are just a smattering of examples.

"South Africa's succulent karoo flora comprises some 2,500 species of plants found nowhere else - the richest arid-zone flora on Earth - and it's renowned for the beauty of its spring flowers, which depend on marginal winter rainfall." Climate change is forcing the flora to migrate slowly in directions that are incompatible with its continued existence, and this by 2050, 99% of karoo are expected to disappear. Similarly, "to the south of the Cape Fold Mountains is the fabulous fynbos, one of six floral kingdoms on Earth, and the most diverse plant community to be found outside the rain forests." Because of local geographical features, the fynbos cannot migrate, and therefore is expected to lose "over half of its extent by 2050, and along with that a significant number of its 8,000-odd endemic species." Two-thirds of the 4000 shrubs and small trees in Australia's southwest heathlands are expected to become extinct with only one degree of global warming - an amount all agree is already inevitable.1 It is the lack of migration that will certainly lead to extinction on land of many species of flora, particularly those that climb mountains only to discover there is nowhere further to go - New Guinea's alpine habitat is strongly expected to be destroyed because of this.2 This is important because although alpine habitats make up a mere 35 percent of the earth's surface, they house over 10,000 plant species, along with countless insects and larger animals, and are hence known as "megadiverse regions." All across the world, we are starting to see flora migrate towards an inevitable doom, some at the rate of twenty feet per decade.3 We know three essential things - (1) how climate change will affect mountain habitats, (2) how much crisis these habitats can take, (3) exactly when mountain species will become extinct based on the necessary rate of ascent up their mountains and the height of the mountain.4

One area of obvious public concern is the Amazonian rainforests, although this area became a source of grave concern to the Hadley Centre in the 1990s after they rain the HadCM3LC global circulation model which included approximations for the Earth's vegetation. The model suggested used the fact that the rainforests create their own rain, and that increased carbon dioxide in the atmosphere meant that plants opened the breathing holes in their stomata for a shorter time to collect CO2, and as a result of being open for less transpiration, caused less rain to fall. Unfortunately, because of a predicted sizeable drop in Amazonian rainfall, a positive feedback loop would take hold in which the land would turn from being a carbon sink (absorber) into a carbon source (emitter). The rainfall would slump, the Amazon would collapse and a basin-wide increase in temperature of 10F would lead to the Amazon becoming mainly grassland or desert, and the atmosphere containing 1000 ppm of CO2 by 2100 rather than the predicted 710 ppm.5 What we know already is that during the last 40 years, nearly 20% of the Amazon has been cut down, and that this has contributed towards serious droughts, such as in 2005, where water levels were reduced by up to 40 feet.6 Recently, concern has continued to grow about the Amazon because of new projects to upgrade road and river transport, as well as plans to create dams and lay down extensive power and communications cabling. Conservation International has said that these projects "could see the loss of the entire Amazon jungle within 40 years."7

Just as with the poles, though, it is not just flora, but fauna also that are exposed to serious climate change effects. In 2004, in a study published in Nature, Chris Thomas calculated that even with the lowest level of inevitable global warming, around 18% of all species will become extinct. At the top end of predicted levels of warming, as many as 25% could become extinct. Unfortunately, it is now realised that these figures assumed migration, whereas human beings have turned the natural world into a series of disconnected islands that make migration impossible. It is therefore understood that the actual extinction figures will be much larger.

Amphibians are at particular risk of extinction as a result of climate change. The inevitable 2F rise in temperature is enough to render the Thornton Peak nursery frog (Cophixalus sp.) extinct. It will follow in the footsteps of perhaps the most famous climate-change amphibian, the Golden Toad. Living on the slopes of Monteverde, the Golden Toad was the first species whose extinction in 1989 could unquestionably be attributed to climate change - in this case, by virtue of the drying out of the surrounding area to the point that breeding pools ran dry, as well as the increased tendency of mistless days that led to the desiccation of the toads themselves. Other amphibians that have become extinct include the cloud forest anole (norops tropidolepis) and the montane anole (norops altae).8

"When the first global survey of amphibians was completed in 2004, it revealed that almost a third of the world's 6,000-odd species were threatened with extinction. Many of these endangered species began their decline after 1976, and according to Simon Stuart of the International Union for the Conservation of Nature, "There's almost no evidence of recovery."9

Close to home, the UK's rarest insect - the streaked bombardier beetle - which exists only on a brownfield site in the Thames Estuary, looks set to become extinct because the site is due to be redeveloped. The extinction would be perhaps made even crueler by the realisation that the beetle was only discovered two years ago.10

It is certain that we have committed an extraordinary number of species to extinction already. If we continue to behave as we currently do, nearly 60% of species known today are likely to become extinct. "A study published in science journal Nature in January 2004 concluded that, if mid-range predictions for greenhouse emissions and the climate's sensitivity to them prove correct, 15-37% of the world's plant and animal species will be "committed to extinction" by 2050."11 But, if we do act now, we can halt the extinction of two species for every one species that must become extinct. We know for sure that we can stem the tide of extinction.12Unfortunately, we cannot just set up protective sanctuaries because, as we have seen, the very climate for these species is changing and they often have to move to find appropriate habitats. Instead, we have to treat the problem at its source - by seriously limiting our emissions.13

It should be noted that one group of species will gain from climate change - the groups of parasites that cause malaria. There are already places in the world that are inaccessible to human beings because of malaria, such as below Mt. Hagen in Papua, New Guinea. Since malaria is set to spread with increased intense rainfall, one of the outcomes of global warming, this means that human populations will be affected by the spread of malaria.14 The Independent newspaper reported (May 26th 2008) that the Asian Tiger Mosquito (Aedes albopictus) has now established itself in Italy, and that the Government's Health Protection Agency is concerned about their establishment in the UK, bringing chikungunya fever, dengue or yellow fever. While not necessarily complaining about these ailments, it should be noted that in 2007, NHS Direct received an unprecedented number of calls about insect, particularly mosquito, bites.15 In Peru, malaria was almost wiped out 40 years ago, but in 2007 over 64,000 cases were registered. It is widely recognised that the case of the rapid increase is because of climate change and deforestation, since off-season rain has allowed puddles of stagnant water to form. The effects of deforestation are also noticeable, since malaria has now spread to areas where logging has been extensive.16

The importance of the spread of malaria cannot be underestimated. The most virulent malaria parasite is plasmodium falciparum, which causes about half of the world's cases. It attacks the brain with alarming speed, so that "an African youth can be happily playing soccer in the morning and dead of falciparum malaria that night. Falciparum is a major reason nearly 20 percent of all Zambian babies do not live to see their fifth birthday."17 Malaria was at one point on the brink of extinction, but in 1962 after the publication of the book Silent Spring, DDT, which had been sprayed lightly on potentially infected homes, became virtually impossible to procure. So the chemical that was halting the spread of malaria ended up being effectively withdrawn from the market because it was poisoning so many other species. "The ban on DDT...may have killed 20 million children."18 Renewed DDT spraying has started to decrease cases on infection in some countries, but the long-term environmental cost of this cannot be ascertained.

1. Flannery (2005), p. 180-1 Describes national parks as "islands in a sea of human-modified environments"
2. Flannery (2005), p. 172-3
3. Flannery (2005), p. 173-4
4. Flannery (2005), p. 172
5. Flannery (2005), p. 196-8
6. National Geographic, Jan 2007, p. 49
7. The Gurdian newspaper, 2nd Oct 2007, p. 17
8. Flannery (2005), p. 115, 118-9
9. Flannery (2005), p. 121
10. The Independent newspaper, Oct 5th 2007, p. 17
11. Clark (2006), p. 10
12. Flannery (2005), p. 183
13. Flannery (2005), p. 176-7
14. Flannery (2005), p. 176-6
15. The Independent newspaper, Aug 17th 2007
16. The Gurdian newspaper, 30th Oct 2007, p. 17
17. National Geographic, Jul 2007, p. 41
18. National Geographic, Jul 2007, p. 50