Earth's sixth mass extinction is underway - but are we bothered. 


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Earth's sixth mass extinction is underway - but are we bothered.



Five times in the past 440 million years, life on earth has suffered a mass extinction eliminating between half and 97 per cent of species. In the words of the paleoanthropologist and conservationist Richard Leakey, such events “restructure the biosphere”. Life takes millions of years to recover – and only does so by undergoing fundamental changes, such as mammals succeeding dinosaurs.

We are on the breaking tip of a sixth great wave of extinction the likes of which have not been seen on Earth for at least 65 million years. And while past ones have been blamed on intense warming or cooling of the climate, or asteroid impact, this is in danger of being the first to have been brought about by one of the very species ultimately at risk – ourselves. This is the alarming finding of a study published this month in the journal Science Advances. The research was designed to determine how human actions over the past 500 years have affected the extinction rates of vertebrates: mammals, fish, birds, reptiles and amphibians. It found a clear signal of elevated species loss which has markedly accelerated over the past couple of hundred years. Terrestrial and marine creatures have each slumped by 39 per cent, it adds, while freshwater ones have done almost twice as badly, crashing by 76 per cent. In all, the report concludes, there are 52 per cent fewer vertebrates alive on Earth than there were when someone now in their forties was born. These particular outer branches of the great tree of life have stopped. Some of their remains will be preserved, either as fossils in layers of rocks or glass eyed exhibits in museum cabinets. But the Earth will no longer see them scurry or soar, hear them croak or chirp.

Its finding meshes closely with that of another study, reported in The Telegraph in August, which concluded that the number of insects worldwide had fallen by 45 per cent since the Seventies, while human populations had almost doubled. The two reports – together form a rounded picture of what is happening to both vertebrate and invertebrate life.

“Isn’t extinction a natural process?” you may ask. Extinction would not provoke concern if it simply ticked along at a natural rate. Fossils and molecular traces of evolutionary lineages show that species “tick over”—they are born and die—on a million-year timescale. Herein lies an analogy: we humans live for 75 years or so. In a sample of 75 people, one expects one death a year and, in a sample of seven people, one in about a decade. Taking a million years for a species’ lifetime, one expects one in a million to go extinct naturally each year. Equivalently, of the 10,000 known species of bird, one should become extinct every century. The actual rate is a very unnatural one every year—100 times higher.

You may wonder to what extent does this matter? Why should we worry if the natural process of extinction is amplified by humans and our expanding industrialised civilisation? One response to this question essentially points out what the natural world does for us. We depend on ecosystems for example, to provide freshwater, protect against flooding, absorb air pollution, mitigate climate change and provide much of our food, both at land and sea. Particular beneficiaries range from the rich inhabitants of the world’s megacities – more than half of which are vulnerable to natural disasters such as floods and droughts – to the world’s poorest rural people, often almost entirely dependent on their natural surroundings. Not for nothing is it said that the world economy is a wholly owned subsidiary of its environment.

The relationship between species diversity and ecosystem function is very complex and not well understood. There may be gradual and reversible decreases in function with decreased biodiversity. There may be effectively no change until a tipping point occurs. The analogy here is popping out rivets from a plane’s wing. The aircraft will fly unimpaired if a few rivets are removed here or there, but to continue to remove rivets is to move the system closer to catastrophic failure.

And yet the world’s wildlife and wild places have suffered from decades, sometimes centuries, of accelerating assault. Forty per cent of the planet’s forests, for example, have been felled since the 18th century, while 60 per cent of the globe’s “ecosystem services” have been degraded in the past half century alone. And population growth – which, far from slowing down as had been expected, may almost double human numbers this century – and ever-increasing consumption threaten those that remain.

The illegal wildlife trade wreaks horrendous damage on some species: yet another report last month showed that ivory smuggling has tripled over the past decade, while Africa’s black rhinos – poached for their horns – collapsed from 100,000 animals to 2,410 between the Sixties and Nineties. And increasing emissions of carbon dioxide make things far worse, both by warming the climate and by turning the oceans more acidic than they have been for 300 million years.

Establishing national parks and other protected areas can help. Yesterday’s report says wildlife has declined less than half as much in them, and some – such as tigers in Nepal and gorillas in the Congo – have increased markedly. But such areas must be well managed and defended and, even at best, are vulnerable to a climate change forcing species to move out. Curbing the illegal trade is also important, as governments are increasingly realising.

In the end, though, the only solution is for the species doing the damage to tread more lightly. That does not mean living less well, only less wastefully. There are signs that it is beginning to happen. The report says that Brazil, Turkey – and even China – are on track to achieve the same standard of living as Germany in the Eighties, with smaller ecological footprints per person. Yet humanity as a whole is still consuming each year what it would take one-and-a-half planets to provide sustainably.

This latest research tells us what we already knew. Humans have in the space of a few centuries swung a wrecking ball through the Earth’s biosphere. Liquidating biodiversity to produce products and services has an end point. Science is starting to sketch out what that end point could look like but it cannot tell us why to stop before we reach it. If we regard the Earth as nothing more than a source of resources and a sink for our pollution, if we value other species only in terms of what they can provide to us, then we will continue to unpick the fabric of life. Remove further rivets from spaceship earth.

 

2. Answer the following questions and do the given tasks.

1) How is the looming wave of extinction different from the previous ones?

2) Speak about the alarming findings proving that the sixth mass extinction is underway.

3) Is extinction a natural process?

4) What is the impact of decreased biodiversity on humanity?

5) Comment on the analogy with the rivets of an aircraft.

6) Prove that the world economy is a wholly owned subsidiary of its environment.

7) What steps should be taken to prevent species loss? What are the difficulties entailed in them?

8) What is meant by “treading more lightly”?

 

3. Find in the text metaphors and comment on them.

 

4. 1) Find in the text words that mean movements and sounds produced by animals.

2) Here are some other animal sounds and movements. Which type of animal, bird or insect do you think might make them?

A. Lumber, flit, crawl, flutter, strut, swoop, buck, burrow, frisk, gore, prance, scrabble, paddle, wallow.

B. Buzz, howl, chirp, squawk, hoot, hum, screech, roar, growl, croak, bellow, chatter, squeak, cluck, whine, grunt, bleat, trumpet, hee-haw, pipe, low, caw, snarl, cheep, yowl, yelp.

3) Which of these words can be used figuratively? Use the dictionary to help you.

4) Choose the correct word.

a) The room whined/buzzed with activity as we all scribbled down voluminous notes.

b) The car roared/growled past, then continued out of sight.

c) I used to croak /snarl at everyone I disliked.

d) When our German friends saw us, they hooted/clucked with laughter.

e) ‘So you've come back,’ he squeaked/grunted in a tone that held little welcome.

f) ‘The recession is over,’ piped/trumpeted newspaper headlines this week.

g) He decided he wasn't going to wallow/crawl in self-pity and feel sorry for himself.

h) The thin white curtain, pulled back, fluttered/frisked in the cool air.

i) Up until then Kylie's biggest audience had been an adoring family who watched as she pranced/swooped around the lounge impersonating her favourite pop stars.

j) Journalists are busily goring/burrowing into the business affairs of the prime minister's family.

k) He grasped their hands in turn and beaming, chirped/screeched, ‘Welcome, welcome!’

 

5. Write down the words connected with increasing and decreasing. Compare their valency.

 

Text 2

1. Explain the meaning of the following: wildlife park, safari park, national park, game reserve, protected area, roadside zoo, petting zoo.

2. Work in two groups. Group A read Text 2A, group B read Text 2B. Read your article and find in your text words and word combinations that have these meanings.

TEXT A TEXT B
- in a way that causes harm or damage deliberately and for no acceptable reason; - the state of being kept as a prisoner or in a confined space; - making you feel angry because it seems unfair or wrong; - to stare at somebody/something in a rude or stupid way; - a place where something is stored in large quantities; - deserving to be laughed at rather than taken seriously; - principles or reasons which explain a particular decision, course of action, belief, etc.; - the planned producing of a group of animals or plants; - to put a type of animal, bird or plant back into a region where it once lived; - reared in a zoo; - the borders or edges of a place; - a detailed plan for doing something new, or something that is a model for how something should be done. - a collection of captive animals, frequently exotic, kept for display; a precursor to the modern zoo; - to move someone or something very quickly; - an area surrounded by a fence or wall and used for a particular purpose; - involving death or violence in a shocking way; - an animal that kills and eats other animals; - a long period of time when there is little or no rain and crops die; - to contribute something of value to a discussion, project etc.; - a sudden decline in the number of people or animals; - not happening very often or not existing in many places; - involvement with or influence in the community, especially in the context of social welfare; - to make something stronger or more effective; - the tendency for children to spend less time outdoors than they did in previous generations.

 

 



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