Extinction

[Ollie]

Interesting article by Jeremy Clarkson in the Times recently:

http://www.timesonline.co.uk/tol/comment/columnists/jeremy_clarkson/article1908938.ece

Do you think he has a point? Personally I think there are a few good points in there, but I'm not really sure what to make of the article as a whole!

[MariaD]

"when push comes to shove, the only creatures that really matter are those in our social group. And our children."

It's statements like this that make me dislike Clarkson.

I think he's missed the point somewhat. No, it doesn't make much difference to our children if they don't see a particular species in the wild. However, the extinction of individual species is just one part of a much broader picture.

By destroying a species' habitat and causing it to die out, we not only kill one species, we change the whole ecosystem of an area and reduce biodiversity. We may like to think that all we need to survive is McDonalds and Starbucks, but we depend on those ecosystems to feed us, make the soil fertile and provide the air that we breathe. The results of one extinction may be small, but the results of dozens of extinctions in a short time-span (which is what is currently happening) are unknown.

Add to this the fact that climate change is likely to be a major cause of future extinctions. Climate change isn't just going to affect a few polar bears - it will affect every species on earth, including us.

[Marmot]

But will a species neccessarily die out? increase in temperatures can lead to an increase in photosynthesis and thus there is a greater amount of base level food for animals to eat. Organisms are designed to adapt and evolve, theyve been doing it for millions of years due to natural climatic shifts that have had nothing to do with us. And even if one species does badly another will do better and it will all balance out again. Or if they dont like where they are organsim can migrate to a more temperate area.
Not so easy for the polar bears ill grant you - but then if we werent eating the fish stocks, the seals would be doing better and the bears wouldnt have to travel so far in order to get plentiful supplies of food.

What is more worrying about increase in global temperatures is the present of gas hydrites stored in the permafrost of the north sea, if sea temperatres warm up the frozen sea bed will release this trapped hydrogen which would lead to catastrophic climate change which in comparison to a little temperature rise would be nothing!

[MariaD]

I think the issue is that climate change is currently happening a lot faster than has been usual in the history of this planet.

As you say, gradual change is a driving force behind evolution. However, historically there is evidence to suggest that rapid change can lead to mass extinction - just look at the dinosaurs. If species were good at dealing with rapid change through evolution or migration, they wouldn't currently be going extinct because of loss of habitat and food. Ecosystems can, and do, stop functioning due to changes in environment or the loss of one or more species - eutrophication and the Venice lagoon spring to mind.

You're right that climate change encompasses more than just an increase in temperature alone, which is why I prefer to use the term 'climate change' rather than 'global warming'. Global warming just sounds like it's going to get sunnier and we'll all be able to grow olives in our back gardens.

[David]

I do think it's sad that I can't see t-rex in the wild though, really! And tigers for that matter; I do think large mammals are more important than insects, because there are far fewer of them and they reproduce much slower. Finding a new species of frog is all well and good, but I dont see how that means killing off tigers, a faily unique type of creature, is fine. Like I say, I think it's a shame I'll never get to see a dinosoar etc.

And yes 'only your family and friends are important'
I think being able to go beyond this mentality is one of the things (morality) that sets humans apart from animals. Something Jeremy doesn't seem to have (though personally I don't even think his arguement is relavent, as I'd keep endangered species for purely selfish, let alone selfless reasons).

[MariaD]

Jeremy Clarkson's environmental views are well known for being a bit... er... controversial, though, aren't they?

His turn of phrase is funny, and it sells papers (and his books), but I wouldn't take his views on ecology that seriously.

[newtrekker]

these are good points however archeological evidence suggests as maria says climates are always shifting.
but there have been far larger climate shifts than this one wey before we even found fossil fuels, i my opinion the theory that greenhouse gasses like Co2 and refrigerants like R-12 and HCF-23 (11,700 times more powerful "greenhouse gas" than Co2) are cuasing the climate shift is not conclusive but there not exactly helping i dont think!

[David]

Even if we aren't causing climate change though, I'm sure extinctions of large animals have been caused by human habitat change.

[Marmot]

its not really climate chage thats affecting the tigers, its the loss of habitat through tree felling, or being hunted due to the belief that eating their heart will make the hunter super strong.

other gasses do have a greater green house affect i'll grant, however, its the shear volume of CO2 which is an issue, as well as the fact that it remains in circulation for up to 1000 years before its drawn down into a carbon sink - a way in which a molecule is effectively removed from the system.
Geologically speaking we've only recently left an ice age, and past records (proxys from ice cores, peat bog sediments etc) all show that after an ice age the global climate always rebounds before settling.
Infact the high levels of greenhouse gasses in the atmosphere meant we avoided a predicted cold patch due to our increased warmth. This cold patch would have significantly affected crop yields and elad to food shortages.

Im just playing devils advocate, but it is good see both sides of the debate. The rebound of temperatures can be accounted for upto about the 1950s, but yes, human induced carbon release "probably" accounts for the further increased temperature rise.

the current working hypotheis of the dinosaur extinction is the meteorite impact at Chucxulub, measuing about 10km across - resulting in an impact force of 100 million meg tons, sent up sulphur clouds which along with debris from the impact blocked out the sun for nearly 2 years, caused a massive short term cooling, and then due to the release of CO2 and other greenhouse gasses lead to a world wide global warming - and its supposedly these two shifts which eventually knocked out the dinosaurs. Smaller mammals which were burrowing where able to survive in their holes, rodents and scavengers were able to survive by living off all the carcasses, those in fresh water where buffetted by the water column and those at high altitudes seemed to have escaped.
Actually i say knocked out the dinosaurs, parrots, pigeons, swallows, birds in general. all have a lineage back to the dinosaurs

[David]

up to 1000 years

Come on - we both know that that doesn't mean anything like what you are implying it does.

[Marmot]

good thing you made me double check that - fell into the trap of sensationalism and got confused on my zeros. The residence time is only a 100 years, but the implication is still the same, a CO2 molecule is still going to adding to the warmth of the atmosphere a 100 years after its release - the implication is that even if all carbon emissions ceased right this second, the carbon dioxide already present will continue to act as a beafed up blanket for another 100 years

[newtrekker]

in a life cycle of a planet 100 years in nothing really but the point is still valid, with the population of humans increasing exponentially every year i dont see any way of stopping the destruction of forests and so on for farmland or housing, this does not by any stretch mean i agree with loosing forests or species but the point still remains this planet just wont be big enough for humans to co-exist with everything else soon. what with lack of space, oil reserves running low, food prices soaring international relations wearing thin and natural disasters popping up all over the shop i think the next hundred years or so are gunna hold some real tough times for a lot of people.

[David]

By 'residence time' do you mean the mean time a molecule will be present in the atmosphere, or still the 'highest likely' time? Also, is the human population really still increasing exponentially? I hope not!!

[Marmot]

- it does depend which report you use as which definition is used, theres also the label of "transit time", "response time", "e-folding time", "turnover time", "adjustment time" - not the simplest by any means.

its looking prett steap for the forseable future!
http://japanfocus.org/images/UserFiles/Image/2456.asahi.jasglobalcontributor/World%20Population%20Growth%20to%202050.JPG
10 billion by 2050

[David]

ugh. I hope those predictions don't come true. Don't think this is the place for my rather hard line views on population control though.