Humans a Natural Disaster?

The history of this planet has seen 5 mass extinctions, suspected of being caused by natural disasters, such as asteroid strikes, volcanic eruptions or sudden shifts in the planet's climate. These extinctions happened 440, 375, 250, 205 and 65 million years ago. It is currently believed that humans are causing the 6th major extinction, larger than that of the dinosaurs 65 million years ago. It is estimated that the current species loss of this planet is 1,000 times as great as it has ever been and is a direct result of human activities.

The World Conservation Union says that there are 844 plants and animals known to have gone extinct in the last 500 years, though they believe that this number is a large understatement. IUCN Red list says the number 784 with 65 species found only in captivity. Sadly, habitat change, habitat loss and the over-exploitation of resources directly cause loss of biodiversity, which shows no sign of abating and is, in fact, increasing. We have, over the years, placed 12% of the Earth's land surface under protected areas, but only 0.6% of the Earth's oceans and we are still grossly abusing our fresh water and timber. Between 1990-2000, we were losing 8.9 million hectares of forest a year, which we have slightly reduced the last 5 years to 7.3 million hectares a year (which is an area about the size of Ireland). We still do not know just how many plant, animal and insect species share this planet with us, but it is believed that 1/5 of them will be extinct in the next 30 years and the number of known threatened species has reached 16,119 from 2003's 12,000 (a 15% increase from the 2002 red list, adding more than 2,000 species).

About 300 invasive species have been introduced into the Mediterranean since the late 19th century, coming in from the Red Sea since the opening of the Suez Canal. Half of the coastlines and nearly 60% of the coral reefs on the planet are threatened with overdevelopment, pollution, and overfishing. CO2 levels are not only increasing global temperatures, but are increasing the acidity of our seas. Naturally, the oceans have a pH of 8.2, but the rate of CO2 input is almost 50 times the normal rate and it is estimated that pH levels will drop to 7.7 in less than 100 years. CO2 levels are rising and dissolving into the oceans to create carbonic acid is happening so quickly that sea dwellers are unable to absorb it, increasing the acidity of the water. A little carbonic acid is beneficial and, in fact, is needed by coral and other species (like crabs, oysters and mussels) in order for them to build and repair their shells, but these shells are made of calcium carbonate (the same substance as chalk) and the building acidity actually dissolves this. These species may die out, unable to build or repair their shells. Some may be able to rebuild their shells, but it is doubtful that they would be able to reproduce. The loss of these spells trouble for the larger marine life, such as salmon, mackerel, herring, cod and baleen whales, who feed on those species most threatened by rising acidity.

Nearly 70% of fish species are either fully exploited or overexploited by humans. Mercury contamination has increased by a factor of five in the Baltic Sea and 85% of marine species have disappeared from the Black Sea due to humans using the oceans and other bodies of water as dumps for waste. In America, freshwater fish face a rate of extinction of 37%. That rate is 42% in Europe and 67% in South Africa. Over-fishing also affects the slow-growing species of our oceans. Of the 547 species of sharks and rays listed, 20% are threatened with extinction. Squatina squatina, the angel shark, has been declared extinct in the North Sea and the Dipturus batis, common skate, has become extremely scarce in the Irish and southern North Seas. Extending fisheries have reduced local populations of Centrophorus granulosus, the gulper shark, up to 95%. Of the 252 species of freshwater fish in the Mediterranean, 56% are threatened with extinction; higher than any other regional assessment of freshwater fish. Alburnus akili in Turkey and Telestes ukliva in Croatia are extinct. 1/3 (174 of the 564) species of dragonfly and damselfly are threatened with extinction. A study that took 10 years to complete says that 90% of all large fish have disappeared from the world's oceans in the past 50 years, due to industrial fishing.

More than 10% of all bird species, 25% of all mammals, and 50% of all primates are threatended with extinction. Out of an estimated 10,000 bird species, 1,100 are on the edge of extinction. Between 1992 and 1995, the Cape Sable sparrow population dropped by 60%, falling from a healthy 6,400 to 2,600 despite the fact that they inhabit a 1.5 million acre national park. However, water management companies feel that the drying Everglades are a nice place to dump excess water, which means that the nesting habits of the Cape Sable sparrow and of many other birds in the area are being disrupted by the increase of water. With global warming an increasing problem and summer sea ice expected to decrease between 50% to 100% in the next 100 years, the polar bear populations are expected to decline 30% in the next 45 years. For years, they have been conservation dependant, but they have been moved onto the list of threatened species. Retreating sea ice is also threatening the walrus populations. We pay little attention to the biodiversity of the Earth's deserts, but the Gazella dama population has decreased by 80% in the last ten years due to unregulated hunting and habitat degradation and may well follow the path of the Oryx dammah. Of the 625 species of known primates, it is estimated that 25% are likely to disappear in the next 20 years. Among the 5 most endangered primates are the golden-headed langur of Vietnam and the Hainan gibbon of China, whose populations numbering only in the dozens. There remain only a few thousand wild tigers in the world and Africa's lion population has seen a 90% decline in the past 20 years, going from an estimated 200,000 to 23,000. 1/5 of all the animals in the US are at risk of extinction.

Botanists say that 1 in 8 plants are at risk of becoming extinct, while fully 1/6 of plants in the US are threatened with extinction. Of 242,000 plant species surveyed by the World Conservation Union in 1997, one out of every 8 (so, 33,000 species) was threatened with extinction. Thousands of our known medicinal plants are being harvested into extinction. The Royal Botanic Gardens in London contains a collection of plants that have since gone extinct in the wild. It is hoped that some may be returned to their native habitat under favourable conditions, but, for some, that is impossible. I remember learning about the last remaining Tazmanian Devil in primary school, and how it died in captivity. The last remaining Encephalartos woodii currently lives in the Royal Botanic Gardens with no hope of restauring the species. There are few Encephalartos woodii trees alive today and all are a clone of the last remaining male specimen, with no female tree with which this species can naturally reproduce.

How many more species will suffer the same fate because of our actions? Biodiversity is known to be beneficial to all life. Take corn for example: The corn crop in the US was almost completely wiped out by a leaf fungus, but was saved by mixing it with a species of wild corn from Mexico. At the very least, we are depriving ourselves of medicines and cures, both known and as-yet-undiscovered. 47 of our major drugs were produced from flowering plants found in rain forests with an estimated 320 valuable drugs remaining undiscovered. On the consumption level: Historically, appriximately 7000 plant species have been used as food and today, 30 of these provide 95% of our food. Over 70,000 plant species are edible and many provide better nutrition than those 30 we rely on so heavily.

If the state of the planet doesn't concern you, perhaps the knowledge that you are causing yourself and your decendants harm by depriving them of the biodiversity needed for survival will make you stop and think a little. If we humans are the cause of this 6th mass extinction, then we have the power to avert it. We have the power to be the sollution and not the problem.