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Originally Posted by Denie
Actually, it is your ignorance on the subject that needs to be addressed. Read...
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't cause global warming? The answer is no.
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I know that CO2 is a greenhouse gas. But it's a weak greenhouse gas and humans only add a few percent of the total to the atmosphere and the US only adds 25% of this few percent to the atmosphere.
My beef is with people who claim or imply that the ice core graphs of temp and CO2 is proof of CO2 causing the warming on the graphs. As far as I'm concerned, this is a lie and/or deceptive. And the lag is also making me question claims about CO2.
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Originally Posted by Denie
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.
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Could have" is the key here.
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Originally Posted by Denie
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.
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If I am not mistaken, the temperature also falls hundreds of years
before the CO2 falls. If true, this to me strongly suggests that CO2 isn't really causing any temp changes on those ice core graphs.
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Originally Posted by Denie
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.
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I noticed that the graphs of ice core and temp show a cycle. I wonder if it's a 21,000 year cycle?
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Originally Posted by Denie
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.
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If it does amplify, I don't see anything that indicates a large amplification.
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Originally Posted by Denie
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.]
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Might be stored" is the key here. They don't know.
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Originally Posted by Denie
And now for your sunspots...
Many researchers have tried to link sunspot activity to climate change, but the new results cannot be used to explain global warming, according to the scientists who did the study." [/b] Link. |
But there is evidence that during past periods of low sunspot activity, the earth was cooler. Conversely, there is evidence that during periods of high sunspots, the earth was warmer.
There is even evidence that shows sunspots affecting the surface temperature of the ocean.
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(b) The globally averaged sea surface temperatures are plotted with the sunspot numbers (Reid; 1999). Both sunspot number and solar cycle length are proxies for the amount of solar energy that Earth receives. The similarity of these curves is evidence that the sun has influenced the climate of the last 150 years.
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The Sun-Climate Connection (Did Sunspots Sink the Titanic?)
Does Gore imply in his movie that stronger hurricanes are the result of GW? Here is what realclimate says about Gore and his movie:
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He also does a very good job in talking about the relationship between sea surface temperature and hurricane intensity.
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RealClimate » Al Gore’s movie
I don't think he's seen the above graph.
Doesn't it seem like an improbable coincidence that both mars and earth started heating up at about the same time and by about the same temp and both have been subjected to the last 70 years of higher sunspot activity? Mars is our neighbor planet and if the sun was affecting earth, it seems to me that it would affect Mars as well (but of course to a different degree).
Kramer