Additional Details
7 months ago
Guess there is noneWhat does the lag of CO2 behind temperature in ice cores tell us about global warming?
This is an issue that is often misunderstood in the public sphere and media, so it is worth spending some time to explain it and clarify it. At least three careful ice core studies have shown that CO2 starts to rise about 800 years (600-1000 years) after Antarctic temperature during glacial terminations. These terminations are pronounced warming periods that mark the ends of the ice ages that happen every 100,000 years or so.
Does this prove that CO2 doesn%26#039;t cause global warming? The answer is no.
The reason has to do with the fact that the warmings take about 5000 years to be complete. The lag is only 800 years. All that the lag shows is that CO2 did not cause the first 800 years of warming, out of the 5000 year trend. The other 4200 years of warming could in fact have been caused by CO2, as far as we can tell from this ice core data.
The 4200 years of warming make up about 5/6 of the total warming. So CO2 could have caused the last 5/6 of the warming, but could not have caused the first 1/6 of the warming.
It comes as no surprise that other factors besides CO2 affect climate. Changes in the amount of summer sunshine, due to changes in the Earth%26#039;s orbit around the sun that happen every 21,000 years, have long been known to affect the comings and goings of ice ages. Atlantic ocean circulation slowdowns are thought to warm Antarctica, also.
From studying all the available data (not just ice cores), the probable sequence of events at a termination goes something like this. Some (currently unknown) process causes Antarctica and the surrounding ocean to warm. This process also causes CO2 to start rising, about 800 years later. Then CO2 further warms the whole planet, because of its heat-trapping properties. This leads to even further CO2 release. So CO2 during ice ages should be thought of as a %26quot;feedback%26quot;, much like the feedback that results from putting a microphone too near to a loudspeaker.
In other words, CO2 does not initiate the warmings, but acts as an amplifier once they are underway. From model estimates, CO2 (along with other greenhouse gases CH4 and N2O) causes about half of the full glacial-to-interglacial warming.
So, in summary, the lag of CO2 behind temperature doesn%26#039;t tell us much about global warming. [But it may give us a very interesting clue about why CO2 rises at the ends of ice ages. The 800-year lag is about the amount of time required to flush out the deep ocean through natural ocean currents. So CO2 might be stored in the deep ocean during ice ages, and then get released when the climate warms.]
To read more about CO2 and ice cores, see Caillon et al., 2003, Science magazine
Guest Contributor: Jeff Severinghaus
Professor of Geosciences
Scripps Institution of Oceanography
University of California, San Diego.
http://tamino.wordpress.com/2006/12/10/s...
As far as I%26#039;m aware, there isn%26#039;t any other significant discrepancy in the AGW theory, and I%26#039;ve asked skeptics to provide me with such flaws several times. The tropospheric warming is the only valid evidence they%26#039;ve ever come up with.
Most skeptics will claim %26#039;the onus is on you to prove your theory, not us to disprove it%26#039;. However, the body of scientific evidence overwhelmingly supports the AGW theory, and the scientific community agrees on this. It is the accepted theory, and thus the onus is now on skeptics to disprove it. There are %26#039;holes%26#039; in the evolutionary and gravtiational theories, too
Global Warming and Cooling, Ice Ages, a perspective
http://mysite.verizon.net/mhieb/WVFossil...
Sun spot number: correlation with global warming
Solar variations and cosmic rays may be driving climate change
http://motls.blogspot.com/2004/09/sunspo...
NASA Study Finds Increasing Solar Trend That Can Change Climate
http://www.sciencedaily.com/releases/200...
Gengi: That is an article that reviews what other people have said. The way science works, is by criticizing what he said, not who said it. But again we see a typical response. Do not discuss the science, attack the man.
Even when CO2 and temp rises about the same time does not guarantee causation.
Climate is a complex chaotic system, and definite proof one way or another is not going happen.
No theory explains all phenomena perfectly, and one sign of the insanity in AGW is beating down people whenever an anomaly is discovered (like CO2 lagging temp) with ever more fanciful and complicated theories to show why CO2 just has to be the culprit.
Other interesting data, like soot decreasing the reflectivity of the arctic, seem to get kind of pushed aside.
No one knows if anthropogenic CO2 swamps the natural water vapor/clouds feedback loop. No one knows if the enormous uncertainties in all the AGW theories are signficant or not.
Now we do know that people like warm weather. Otherwise people would be abandoning the tropical/temperature climates for Canada, the Arctic, and Antarctica. That is why AGW doesn%26#039;t get any political traction from any gov%26#039;t -- even ones that promise at every opportunity they are %26quot;concerned%26quot; and want to do everything they can. In practice, they don%26#039;t.
Excuuuuuuuuuuuuuuuse me! CO2 lagging temperature is %26quot;misunderstood%26quot;? What the heck is there is misunderstand?
The doctrine is that rising CO2 increases temperature, either leading or lockstep. CO2 lagging doesn%26#039;t support this notion, at all.
Some mysterious happenstance, force, whatever warmed the earth and then CO2 levels rose. But that mysterious force then disappears when CO2 reaches a certain concentration and then CO2 is the major factor.
Hello Occam%26#039;s razor. (Given two explanations that account for the data, pick the shorter one.)
Instead of accepting that no theory accounts for all the loose ends, AGW creates endless tortured explanations.
this is %26quot;Evidence %26quot;.
note this journal is considered to be on the fringes of science (aka pseudoscience). it has also published papers related to UFOs, reincarnation, astrology, cryptozoology, consciousness-related physical anomalies so i don%26#039;t think its review process can be that good or its standards that high.
AGW is also a matter of degrees. There is a world of difference between a slight rise in temperatures and the %26quot;planetary emergency%26quot; that Al Gore portends. Furthermore many of these impending changes could take centuries to play out. People in 1900 couldn%26#039;t begin to imagine the challenges of the 21st century, it%26#039;s unlikely we have an accurate idea of the world 100 years hence.
Anyone who says things like %26quot;the science is in%26quot; and %26quot;the debate is closed%26quot; has zero knowledge of science. The history of science is full of orthodoxy overturned by new discoveries. The truth is there is a lot we don%26#039;t know about the climate and the forces that drive it.
That something hasn%26#039;t or can%26#039;t be disproved doesn%26#039;t make it true. The burden of proof is on those that advance the belief not those who are skeptical. That we don%26#039;t know all that nature does to alter the climate is not proof that we are doing it. Certainly the geological record is proof that nature can cause the effects we see, so that needs to be considered.
The biggest issue I have with AGW isn%26#039;t the science, it%26#039;s the politics. This whole thing looks suspiciously like a panic being generated by people who have a vested interest in scaring the public into surrendering our wealth and our liberties. Whether or not climate change will do more harm than good is still an open question, but history has shown that losing one%26#039;s freedom has never been a good thing.
We should be very suspicious of people who can create a long list of potential disasters without balancing it with potential benefits. Very little in this world is all good or bad.