Andre Jute wrote:

global warming. Except the graph, and all the official statistics from
the IPCC, show that global warming precedes CO2 emissions.


Hiya Andre. I'm normally a lurker here, but can't resist jumping in to
comment. You are wrong in your conclusion that global warming does not
result from CO2 emissions.



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'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 "feedback", 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'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.]



http://www.realclimate.org/index.php...-in-ice-cores/


Jo