I read there is a nominal 800-year lag between a global warmup and the release of CO2 from the oceans.?

Question

My question is this. We had the MWP, about 800 years ago, plus/minus, a good global warmup, even melting the Greenland icecap to a significant extent.

I have yet to see anything published on what part of the reported vast and sudden buildup of CO2 is the delayed CO2 from the MWP, and how much longer this delayed CO2 is expected to continue to come up out of the oceans.

Is there anybody who will comment on this, and maybe cite scientific proofs that a significant part of our present CO2 buildup is or is not related to the delayed CO2 release from the MWP, and therefore is not under man's control at all?

Or a proof that the MWP warming is the one that did NOT release CO2, delayed by hundreds of years, like every other one has in the history of many global warming/cooling cycles?

Anyone care to tackle this, with some reliable citations? And traceable papers? And the President of GM is not in my mind a reliable scientist!

Please folks. I said about 800 years ago. The MWP started back in the 8- or 900's, as I saw the curves, and was a typical global warming, peaking around 1000-1200, and then decaying slowly until the start of the plunge into the LIA.

So if you add 800 years to say 1200, puts us at 2000, and the gas release I am assuming does not all come out as a big sudden bubble.

And I see curves with various roundings, and other statistical manipulations, some of them are said not to apply when they seem to track, like solar activity, which often is left unrounded to be more difficult to read, I think.

And if you want to argue, is not the unprecedented (I hear) dust storm on Mars in line with our earth predictions of huge storms from warming,,,and is not Mars warming? I keep reading no.

But, my question still stands, I have not seen ANY curves showing what proportion of the CO2 levels came from the MWP at any time.

Tell me, what happened this time? Where did that expected CO2 go?

Answer 1

Good observation.

Answer 2

Good skeptical question, based on science and data. For once, I can beat Trevor for length of answer and clarity .

The basic answer is that the MWP was a very minor warming, as these things go. Not remotely enough to release enough CO2 to be a major part of the increase seen in the last 30 years.

Check out this graph of historic CO2 levels.

http://www.globalwarmingart.com/wiki/Image:Carbon_Dioxide_400kyr_Rev_png

The warmings that raised CO2 from about 200-275ppm (from the oceans, where else?) were on the order of 3 degrees C. The MWP was on the order of 0.3C. Assuming it's a linear relationship (not exactly, but that's why I give a wide range in the answer below), that would cause a rise in CO2 of about 5-10 ppm. Not very much compared to what we're seeing.

Once again, excellent question.

Answer 3

It's an excellent question and not one that can be answered quickly.

There's been much talk about the '800 year lag' but it's wrong to call it such, a more accurate description would be an 800 year lead-in period or build-up period.

Imagine you placed a heavy iron bar in a fire, the fire gives off constant heat but the bar doesn't become red hot immediately, it takes perhaps 10 minutes. There's a 10 minute lag between starting to heat the bar and it becoming red hot but all the while the bar is getting hotter and hotter.

It's the same with CO2 and global warming. As soon as the planet starts warming more CO2 is released and the main source of this are the seas and oceans. Unlike the iron bar that only takes 10 minutes to heat up, the seas and oceans are so vast they take about 800 years to heat up. All the time that they're heating they're giving off ever increasing amounts of CO2. Once they start cooling again the amount of CO2 being released starts to drop.

The MWP peaked in approx 1050, 800 years after this coincided with a cooler than average period known as the Little Ice Age (LIA), this graph illustrates it nicely http://www.globalwarmingart.com/wiki/ima...

After the peak of the MWP, CO2 levels started to fall back again and as the planet moved into the LIA they continued to fall, effectively CO2 levels were tracking temperature changes but with a delay because the seas and oceans cool and warmer much slower than the atmosphere does.

If the ambient air temp is greater than the temp of the seas and oceans then they'll keep heating up and more CO2 will be released. It's possible for the atmosphere to be in a cooling phase but as long as it remains warmer than the oceans then the amount of CO2 released from the oceans will continue to increase.

It's also necessary to take a couple of other things into account. One is the atmospheric lifespan or residency period of atmospheric CO2, this is 115 years if there are no external factors involved. The second thing to account for are the external factors, primarily the carbon sinks and sources and their net contribution. For example, the world could be warming, the oceans giving off more CO2 but all the while biomass is acting as a sink and the atmospheric concentration of CO2 could be falling.

For purposes of clarity, the MWP did not correspond to a vast or sudden build-up of CO2. For 17,000 years the general trend in CO2 levels had been a very slow upward one increasing from approx 180 parts per million by volume to 280 ppmv.

I hope this makes sense, add more details or email me if you'd like further info.

Answer 4

You're missing a pretty crucial point - historically when atmospheric CO2 levels were following ~800 years behind global warming, the planet had a pretty constant trend (warming or cooling) for the 800 year period.

http://www.grida.no/climate/vital/02.htm

As you can see, the little bumps in the data don't match up - only the long-term trends do. Over the past 800 years, the planet spent most of the time cooling rather than warming:

http://en.wikipedia.org/wiki/Image:2000_Year_Temperature_Comparison.png

so it makes no sense for the current warming to be due to the MWP.

This is easier to understand if you look at the mechanism for the 800 year delay. As the oceans warm, eventually they begin to release CO2 because carbon dioxide is less soluble in warmer water. Basically rather than absorbing CO2, at a certain temperature the oceans begin to emit CO2, which then increases the greenhouse effect and amplifies global warming. But since the planet has cooled from the MWP (until just recently), the oceans would not have reached this temperature due to the MWP warming.

Now humans are emitting CO2 independent of the global temperature, which is why there's not currently an 800 year delay between atmospheric CO2 concentrations and global warming.

http://en.wikipedia.org/wiki/Image:Mauna_Loa_Carbon_Dioxide.png
http://www.ncdc.noaa.gov/img/climate/research/2005/ann/global-blended-temp-pg.gif

Answer 5

if you look at a Keeling chart you can see that our current CO2 trend coincides with the Industrial revolution. http://www.whrc.org/resources/online_publications/warming_earth/scientific_evidence.htm Also, in the past CO2 was one of the feedback loops.. in other words something else would trigger global warming, releasing more CO2 which would exacerbate the problem... just like we have feedback loops today of less light being reflected due to a smaller surface area of the highly reflective ice caps. As part of a feedback loop.. it was just another facet of natural global warming... which would inevitably trap a large portion of the carbon in the ground eventually... in todays world.. we are taking carbon that has been trapped in the ground for millions of years and reintroducing it to our atmosphere.. causing a feedback loop to become a primary facilitator of heat trap.

Answer 6

coming from the oceans it the volcano's under the sea that's causing it

Answer 7

none of these 7 studies indicate a warming period 800 years ago:

http://en.wikipedia.org/wiki/Image:1000_Year_Temperature_Comparison.png

this one doesn't either:

http://en.wikipedia.org/wiki/Image:Sunspot-temperature-10000yr.svg

this one kind of does - but 14C not as reliable for solar activity determination:

http://en.wikipedia.org/wiki/Image:Carbon14_with_activity_labels.svg

Answer 8

My answer would be "sort of"