Global Warming and Extinction?

Question

Sorry for the brief dramatic opening, but between the Permian period at the end of the Paleozoic age and the beginning of the Triassic period of the start of the Mesozoic era there seems to be a mass extinction of living things. Obviously, it was not a complete extinction, but this article by Shu Zhong Shen, et al. in Palaeoworld shows a cooling, then a warming and references others that show it was global in nature. Could it be that what we are surmising as Global Warming today is just another of several natural events that periodically happen? There were no humans 248 million years ago, or were there?
http://www.sciencedirect.com/science/journal/1871174X

Answer 1

There are lots of theories on probably the worst mass extinction period on the earth, the end of the Permian (actually the last period of the Paleozoic Era). The evidence for there being a period of very low oxygen after this is pretty compelling with the presence of minerals that form in low oxygen environments. Prior to that there was an abundance of oxygen and indicated by the very large insects that can only survive in high oxygen. I have heard theories that volcanic activity in present day Siberia ultimately resulted in heat from CO2 which released methane hydrate which burned and lowered oxygen levels, increased CO2 which further increased methane hydrates in a vicious cycle. I am skeptical of the methane hydrate theory. The ocean at depths of a mile or more are probably not going to be affected enough by rising temperatures on the surface though I am sure that many would disagree.

To me it seems more likely that there is an unknown comet collion on the oposite site of the earth from Siberia at the time of the Permian extinction. The Asteroid sent shock waves around the earth and resulted in massive volcanic eruptions in Siberia.

The same thing happened at the end of the Mesozoic. The comet hit near Mexico sending shock waves around the earth resulting in the outpouring of the Deccan basalts in India (theoretically).

The evidence for the Permian comet was probably subducted beneath another plate. Scientists probably wouldn't want to propose a theory that doesn't have much evidence. They would also like to encorporate something which has modern consequenses such as global warming implying that we might also cause the earth's climate to spin out of control. I just don't think it is very likely in my opinion and mostly idle speculation on their part.

Answer 2

There is evidence for extraterrestrial causes of both of the mass extintions you mention. The first link in sources details a new crater found in Antartica which may have lead to that extinction.

The end-mesozic event certainly helped, if not completely, killed off the dinosaurs and many other species.

The K-T event is a mass extinction, the 2nd largest ever (to the Permo-Triassic) is famous for the large bolide (extraterrestrial object) impact that occured off the Yucatan, creating the Chixulub crater. Glass from the crater is dated to 64.98 +/- .01 million years ago.

This event caused global devistation, evidenced by:
1) Differing Sr ratios from global wildfires
2) Microdiamonds from fried Carbon
3) Tsunami deposits found all over the southeast US
4) Stishovite (a variety of quartz which forms in extreme pressures)
5) Worldwide Iridium anomaly. Ir is usually found abundantly in space, but it is very rare on earth. All over the world, at the K-T layer, the amount of Ir is much higher than normal.

It is theorized that the impact created magnitude 12 earthquakes and blocked the sun for as long as 9 weeks.

However, none of this has anything to do with the current global warming, whihc is certainly human caused.

CO2 is 30% higher than it has been for 650,000 years. Methane is 130% greater. These are two of the main pollutants humans put into the atmosphere in excess, and they are two of the primary greenhouse gases.

Look at the 'hockeystick', which shows a dramatic warming since 1950 after a fairly stable climate for 1000 years. In fact, the 10 hottest years in recorded history have all happened since 1990, with 2005 being the hottest, and 2006 is shaping up to maybe break that record.
(see links below)

How's that for proof of man's fault in this? There is ample proof, any real scientist will tell you that.

There has NEVER been an article doubting man's influence on global warming published in a peer-reviewed journal. A recent study of almost 1000 proved that.

Yes, the earth naturally heats and cools, but the rate and amount we are warming now is unprecedented in the recent geologic past. We are doing this, and we must stop it. This is not some political statement or rhetoric. This is science trying to educate a crass, ignorant public of the damage they are doing. The magnitude of temperature increase ALREADY is about 10x that of the 'little ice age' of the middle ages, and rate and amount are only going up.

Just to be clear, glacial and interglacial cycles are mainly controlled by astronomical fluctuations, but we have a detailed record of the last 7 cycles, and what the climate and CO2 is doing now is way different and extreme. The rate of increase is much higher than in the past AND the value itself is much higher.

HI CO2:
http://news.bbc.co.uk/1/hi/sci/tech/4467420.stm
HOCKEY STICK:
http://news.bbc.co.uk/1/hi/sci/tech/5109188.stm
General climate stuff:
http://news.bbc.co.uk/1/hi/sci/tech/3897061.stm

Answer 3

international warming and international cooling would have an same impact on life. it really is why better than ninety 9% of the life sorts which have ever lived on the earth at the instantaneous are extinct. verify this like for a narrative on how GW killed off the numerous thousands of years in the past. do not ignore that GW is organic and guy has no longer some thing to do with it.

Answer 4

There has been many climate changes in earth's history and they will happen in the future, even without our help.
We have seen a change over the last decades, at the same time that we have released a lot of carbon dioxide. This is maybe to much of a coincidence to believe in.

intelligent_friendlistener, I think it is the other way around 95% of the scientists believe we are causing global warming. That is of course no proof that they are right.

Answer 5

While global warming & cooling are natural events that happen over time, this current "event" appears to be accelerated by human greenhouse gas emissions.

Answer 6

95% of scientists agree with the FACT that this is just another cycle of the Earths climate. Ice core samples everywhere in the world support this. The fact that the newspeople like the doom and gloom outlook of the 5% nay saying scientists - as this is more dramatic and sells paper is laughable. Then that lying inventor Al Gore gets involved and they go into some sort of dispicable estacsy. We have nothing to worry about excep Al Gore farting his so called "greenhouse gas" out his mouth.

Answer 7

its the cycle of the world, regardless of what they say the world is actually getting cooler, and we are way overdue for another iceage, i fear there is too much info to be putting into this little space so i wont bother, email me if you want more of a talk on it though :D

Answer 8

greenhouse gases & acceleration of warming?