Is the current 'mass extinction' worisome?

Great Debates
1

"A detailed survey of birds and butterflies in Britain shows a population decline of 54 percent to 71 percent, a finding that suggests the world may be undergoing another major extinction.

Researchers said the study helps support the theory that the sixth big extinction in Earth’s history is under way, and this one is caused by humans."
Is it true that humans are causing a mass extinction on par with the past ones caused by climate change or asteriods?

If so, what does this mean for our future? Can we just live without these plants and animals?

Do we have the moral responsibility to try to save non-useful species?

2

Oops, forgot to link.

Here you go: http://www.cnn.com/2004/TECH/science/03/18/wildlife.gone.ap/index.html

3

as the sixth time this has happened in general, its clear the sky doesn’t fall. just because something is made by humans does not mean it is “extra bad”, humans are not a tainted race that spews evil into all their works.

to have things go away forever is sad for sure, but this is a pretty normal part of the cycle of life, this is not the first case of a new class of life appearing and haveing the whole world reorganize, early early plants even beat us to the title for “destroying the entire world enviroment with toxic pollution”.

humans adapt better than anything that has ever come before there is virtually no enviroment we can’t live in (under water, hard vaccum, the arctic) and we can eat virtually anything (we basicly eat land and energy right now, the food made on it is almost incidental) so it is unlikely that the enviroment will change to something that is totally unsuportive of humans, since there aren’t that many enviroments anymore that aren’t supportive of humans.

so its bad in a sense that loss is tragic and sad, its unlikely to make the sky fall, or the world end, its something thats gone on since life began, and just because its “unnatural” doesn’t make it special. unnatural is a totally arbitary concept to start with.

4

A mass extinction is a “normal part of life” just because it has happened five times previously in the history of the Earth, the last time more than 60 million years before we came on the scene?

By your argument, another World War that killed 30 million people would not really be any big deal, because, what the hey, we had one of those before and we’re still here.

Yeah, humans will survive, but the world will become a much less interesting and beautiful place.

Because of the loss of diversity, we potentially lose thousands of useful products that could combat disease or be used to increase crop productivity.

Because of the disruption of ecosystems, we make the environment much less pleasant and useful for ourselves.

5

While extinction in general is the eventual fate of all species, I would not claim that major events such as the Big 5 are even remotely a “normal part of the cycle of life”. Those events stand out precisely because they were so extraordinary. They were catastrophic extinctions against the steady background of extinctions.

6

There is no evidence to say that all species go extinct. I think it is a natural event (otherwise it would not be occuring). We are unlikely to destroy life on Earth, however, we may very well destroy ourselves. I am roundly against destroying ourselves, I like life and I want to continue enjoying it for as long as I can. Medical science has proven that our cells are programmed to switch off after a certain point, so I believe that we can deprogram these cells and I could ostensibly live forever. However, to live forever I would have to accept certain things, like the inevitable extinction of species, the death of untold numbers of friends and relatives, survive wars, and endure any hardship. I feel that I am prepared to do this, as I have not yet experienced anything that would make me feel otherwise.

However, regardless of how you feel about my chances of achieving immortality, I do think that the ecological damage we have wrought on the world is going to take it’s toll within my lifetime, in fact I think it will happen within my youth. The sky WILL fall, and as our society is global, and no longer specific to a region, it will affect all of humanity, instead of just our ‘known’ world like the Black Plague for instance. Sure they knew about realms outside of their own, just as we have landed on the moon, but they were not terribly affected in a daily way by what someone did on the other side of the planet, the way I am directly impacted by the war in Iraq.

Therefore I believe that those unable to see the inevitable catastrophe (and most of the people who are capable of seeing it) will be wiped out by the coming problems. Famines and Pestilences cause the spread of war, anyone that pays attention to African politics can see this without even looking for a historical example. There are enough issues with the environment that are causing damage NOW, that we don’t need to look too far in the future to see a catastrophic scenario. America the largest empire ever built with the largest most technologically advanced military ever assembled is rolling across the most religiously fanatic land in the entire world, while supporting the second deadliest military in the world. Biblical prophecy is going to come to pass and it’s only the logical extension of the greed that we’ve put forth, and not some big mystical idea that some mushroom cap eating saint needs to write about at this point.

Everyone I talk to in America seems pretty unwilling to give up their capitalist lifestyle, and I don’t see people willing to say “Yes I will accept any economic consequences whatsoever just bring ALL OF OUR TROOPS EVERYWHERE home.”, I don’t see that happening, so I see World War III around the bend as environmental disaster after environmental disaster occurs, with the spread of AIDS going unchecked in the third world.

The decision to me is clear, it’s find those that you trust, and make a tight knit society of people, and don’t associate with ANYONE that would put ANY amount of money over their relationship with you, because things are going to break down as America begins to lose everything in a time where Productivity is outpacing job growth, the money is increasingly being funneled into the pockets of those that already have most of it. When the dollar falls, and I believe that it will, sooner rather than later, the global impact is going to be like a house of cards, I don’t think speculating in Euros will help you unless your plan is to bail on your euros the moment the dollar collapses capitalizing on it’s sudden increase in value by spending it in the American economy.

So I don’t believe everyone is going to die, but I believe that most people will. People HAVE said the sky is falling for ages, it HAS fallen for ages depending upon your view of scale, and this time we have a global economy, nuclear weapons, and worldwide ecological damage done by industrialization. You may not agree, but I think it’s a foregone conclusion at this point, and the only reason I think that is because when I propose the pragmatic tribalism that has me living WAY BEYOND my ability to bring dollars into my pocket is too idealistic because people are greedy. Well then, let them choke on their dollars when there is nothing else to eat. We’ve been sowing for a long time, I think it’s time to reap the harvest.

Erek

7

the only reason I think that is because when I propose the pragmatic tribalism that has me living WAY BEYOND my ability to bring dollars into my pocket people tell me its too idealistic because people are greedy.

8

it depends how you count a “big deal” a world war that killed 30 million would be a huge sad tragic event, that should be avoided, but it would not be the end of the world, as over 5 and a half billion people would survive. its something to avoid, and if it happens it will be horribly sad, but its not going to make the sky fall and have us all be corpses.

9

[QUOTE=autz]
"A detailed survey of birds and butterflies in Britain shows a population decline of 54 percent to 71 percent, a finding that suggests the world may be undergoing another major extinction.

[QUOTE]

How about looking at the more reasonable conclusion?

Britain is a very closely populated island, and has been for millenia. For most of that time the native people engaged in agriculture using small fields defined by hedgerows. Hedgerwos are literally hedges used as fences. With the coming of modern machinery the small fields, small enough to be ploughed by one man and a horse, were amalgmated into large fields that could make better use of tractors. The hedgerows were seen as a waste of space and resources and were torn up and replaced with barbed wire.

That is the situation in Britain. The island is already depauperate WRT to birds and butterflies, which means that the loss of even one species is a significant percentage. And then the people go and tear up the the hedgerows, which were the last woody vegetaion over huge areas. These hedgerows represented nesting sites, shelter, larval food, flowers as well as dispersal corridors. Naturally rmeoving them was disastrous. It has become the equaivalent of destroying all the forst over 90% of the land area.

That is the single biggest reaosn why there has been such a serious species decline. This isn’t evidence of a mass ectinction. It’s evidence of a depauperate system that has ben subjected to removal of one of its primary ecologiucal niches. Of course there will be extinctions that make up a large percentage of what is left. But Britain is the worst case exam[ple. It is highly atypical and the results can’t be extrapolated globally as this article has done.

10

As far as life goes, keep in mind extinction is a rather continual, not episodic, thing.

The big 5 were extreme so they get the press, but they are the hurricanes to the everyday rain of background extinctions.

This information may simply imply that we’re in for some hail.

Got your waders? :slight_smile:

11

So as long as humans don’t actually go extinct, you’re not too worried about things, no matter how unpleasant and impoverished the world becomes?

12

The significant part of this study is that it is documenting the fact that extinctions are affecting insects - which make up about half of all described species - as well as larger organisms. Britain is one of the few places where the distributions of insects are well enough known for such a study to have been done.

There is ample evidence from elsewhere that extinction rates for macrofauna such as birds, mammals, etc. are far higher now than the normal “background” rate of extinction, and higher than they have been anytime since the end of the Cretaceous, the last major extinction event.

Britain is very far from a worst case scenario, because, as you say it is already depauperate. Hawaii surely is much much worse. I am sure if an equivalent study could be done in Java, which is far more diverse than Britain or Hawaii but which has been severely affected by deforestation and other habitat change, declines in a much larger number of species would be documented. However, the capacity to conduct such a study doesn’t exist at this time.

13

Did not exist 100,000 years ago. Hence all of the diverse life forms seen there today came into being in the past 100,000 years. So, bad as the current loss of species is, there is hope that new species will come about quite rapidly in such tropical environments. In temperate climates species generation is much slower…however, the same thing happens.
I think there is much more danger in having foreign species invading local habitats-the example of the malaleuca tree in Florida comes to mind. Some idiot imported these from Australia, and they are taking over the native forests…not only do they crowd out the native trees, but they burn with terrific intensity-forest fires in S. Florida are now a common occurence.

14

This is incorrect. In the past it has been highly debated whether continuous rainforest exisited in the Amazon basin during the Pleistocene, or whether it was reduced to separate core areas (refugia) by climatic changes. Regardless of which of these scenarios is correct, there is no doubt there has been rainforest in at least part of Amazonia for tens of millions of years. Recent genetic work has largely refuted the refugia hypothesis as the factor generating biodiversity in Amazonia. Many of these species are millions of years old and long predate the Pleistocene. There is absolutely no way that speciation rates as presently understood could keep of with the very high rate of extinction now going on.

15

Actually, it’s unimportant what is causing the loss of diversity. The real questions are what effect it will have on us, and what we can do to mitigate it. True, knowing the causes might help prevent extinctions, but surely there are ways to improve species diversity that will work not matter what the ultimate causes of the loss are.

16

Overwhelmingly the most important cause of recent extinctions has been human activity: most significantly habitat loss due to conversion to other land uses (agriculture, forestry, urbanization), but also including overharvest (hunting, fishing), introduction of exotic species (predators, competitors), introduction of diseases, and pollution.

The only hope of preventing such extinctions is to understand what the causes are. What strategy would you propose that would work against all those causes?

17

I think you misunderstood what I meant (i.e., I didn’t explain it very well). My point was that the specific cause is not important. For example, we can increase species diversity by expanding natural habitats. It doesn’t matter if the original loss of diversity was caused by habitat loss, overhunting, exotic species, or pollution (and these could be due to human activity or natural forces). Providing species more habitat simply increases their survival.

Stopping particular sources of diversity loss is important, but we can do things to improve species survival without determining the exact cause in any specific case.


I personally believe species diversity is a good thing and a worthwhile goal for humanity.  But what scientific evidence is there that preserving diversity is useful for humans?  While "we don't know what we're losing" is something, is there anything more tangible?  I'm hoping for something like "regions with high species diversity suffer less from disease X", or fewer floods, or higher humidity, etc.
18

OK, in general increasing the amount of natural habitat will benefit a variety of species. However, in specific cases where the cause of decline is due to some other factor, simply preserving the habitat won’t do any good. I used to work for the N.Z. Wildlife Service, where there is a severe problem with introduced predators (feral cats, weasels, rats). Even in otherwise pristine habitat, these species have wiped out certain birds. I worked on an island where the forest was primeval, but where feral cats were in the process of eradicating several species. The Wildlife Service had to get rid of the cats to save the birds, not merely protect the forest. Likewise, in the Hawaiian Islands, many birds have become extinct or are on the verge of extinction due to introduced avian malaria. There is not much we can do to save these birds even if we protect the habitat.

You’ve heard of Taxol, derived from yew trees and used to treat breast cancer? A high percentage of medicines contain compounds derived or developed from natural products. And wild ancestors of domestic plants have been used to provide genes for disease resistance to crops. I work with people here who are actively involved in “biodiversity prospecting,” looking for useful drugs by sampling tropical forest plants and coral reef organisms. They have had recent “hits” in finding compounds active against malaria and leishmaniasis (a tropical disease). It’s still a long way to the development of a marketable drug, but the potential is there. And there are many many species that contain what could be useful compounds - only the tiniest fraction have ever been tested.

It has been demonstrated in the Amazon and in Costa Rica that deforestation has changed and decreased regional rainfall. Although this is an ecosystem effect, and not one of biodiversity per se, biodiversity is important in maintaining the functioning of these ecosystem. For example, one of my colleagues has recently shown that overhunting, by removing the animals that disperse seeds, is producing changes in forest composition.

I could go on for several pages on this topic, but suffice it to say that yeah, there’s plenty of evidence that biodiversity is useful to humans.

19

The Value of Biodiversity

This is just one of many such articles than can be found on the net.

20

Of course butterflies are at least as dependant on the existence of hedgrerows as birds. Possibly moreso sine the larvae often have very narrow food requirements. Remove all woody plants within 10 km and many of those species that rely on woody plants will die, no question.

While that is probably true it is also very open to interpretation. Most species don’t leave any fossil remains at all. Moreover of those remains we do have most would not be sufficient to determine species status with any certainty. Many species today are known only through minor or superficial morphological or even genetic differences that would never or rarely be preserved in fossils. So at best we have a rough estimate of species diversity in the past.

We have an even rougher estimate of previous extinction events. For example around 50, 000 years ago vast areas of ‘jungle’ vanished from northern and central Australia due to causes yet to be determined. Pollen analyses suggest plant species diversity equivalent to the more depauperate rainforest, which is still an order of magnitude higher than the sclerophyll woodlands found in the same area today. Then we have other examples. The prairies of north America being derived from woodland. The need for world reef systems to move to cope with sea level changes, which must result in extinctions. The loss of gallery forests in Africa. The transformation of forests in NZ after the arrival of people. The deforestation of Europe etc.

So what was the extinction rate for such massive changes over many large areas? We have absolutely no idea because most species don’t leave fossils that can identify them. It would have been large, but it is not a figure that is factored into any calculation of previous extinction rates I have ever seen. Instead these pre-historic rates are calculated off the known fossil species with some allowance for habitat diversity but never on a scale to cope with these types of massive ecosystem extinctions.

So while I believe that the current extinction rate is on the high side of average I will not be convinced it is the worst since the cretaceous until I see some evidence that these prior ecosystem transformations have been taken into account,

I completely fail to follow your logic here. Britain is depauperate. It is home to only 100 or so birds, many of them occasional visitors. What that means is that a loss of only 2 species represents a catastrophic 2% loss. Were Britain home to 1000 bird species, as might be expected of a similar sized area of tropical island rainforest then the loss of 2 species would be a much less significant 0.2% loss.
I can’t see how being depauperate can fail to make a few extinctions look anything but catastrophic.

The fact that so many of these species of birds and insects only survived at all due to the existence of hedgerows, which are now being demolished serves to make the problem even worse. It really is close to being the worst case scenario. Hawaii may well be worse being tropical and isolated island for so long. But in that case we really are looking at the extreme and. While extrapolating form Hawaii into a global figure would be less valid than doing so for England, that still doesn’t make extrapolating form Britain any more valid. What is happening in England is atypical for a variety of reasons. You can’t just extrapolate from Britain to the whole world with any validity. Not unless you want to posit similar mass deforestation worldwide. Yet this is exactly what these researchers have done.

To me it is just bad science.