Atmospheric CO2 drove climate change during longest interglacial

August 8, 2012

Known as the marine isotope stage 11 (MIS 11), the interglacial period centered around 400,000 years ago was the longest and possibly the warmest interglacial in the past 0.5 million years. Because the orbital configurations, atmospheric greenhouse gas concentrations, climate, and faunal characteristics during MIS 11 closely resemble those of the past 5,000 years, paleoclimatologists use MIS 11 as a geological analogue of the present and the near future.

There exist several high-resolution records documenting almost all aspects of terrestrial and marine climate through MIS 11. However, there is neither a clear understanding about how climactic parameters such as (CO2), , the isotopic makeup of carbon in marine and terrestrial reservoirs, and annual air temperature interact, nor a consensus regarding the major drivers of climate change during this interval.

Using 15 of the most robust proxy records of marine and terrestrial climate, Das Sharma et al. employ new statistical and mathematical techniques to quantify the interactions among climatic parameters and to investigate which of these parameters could be the primary drivers of during MIS 11. The authors find that atmospheric CO2 concentration was indeed the primary driver of both terrestrial and marine climate: Sea surface temperature and the isotopic makeup of carbon in terrestrial and marine reservoirs responded “instantaneously” (i.e., within 1,000 years) to changes in atmospheric CO2 content.

They further report that MIS 11 had warm and cool phases that can be detected from sea surface temperature records alone. During the relatively cold phases, sea surface and air temperatures behave coherently and respond to atmospheric CO2 faster. However, during warmer intervals, ocean surface and air temperatures behave more independently of each other and atmospheric CO2. The authors suggest that over the course of the next century, air and sea surface temperatures are likely to change in ways that will be difficult to predict.

Explore further: Carbon cycling was much smaller during last ice age than in today's climate: study

More information: Sea surface temperatures in cooler climate stages bear more similarity with atmospheric CO2 forcing, Journal of Geophysical Research-Atmospheres, doi: 10.1029/2012JD017725, 2012

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2.5 / 5 (8) Aug 08, 2012
Another nail in the denialist coffin.

What manner of public execution will be most appropriate for them?
2.5 / 5 (8) Aug 08, 2012
Here is the hammer VD! Hangin ain't good enough for em.

2.3 / 5 (3) Aug 09, 2012
Mere facts will not stop denialists. They are the zombies of scientific discourse -shoot them full of holes and they just keep on rambling.
This July was the hottest ever recorded in USA. This will not stop denialists. Even as seas rise to inundate Miami and Rotterdam they will continue to parrot the same old argumants.
2.3 / 5 (3) Aug 09, 2012
Another nail in the denialist coffin.

What manner of public execution will be most appropriate for them?

The inuit used to send the undesirables to sea on an ice flow...when they had ice.
1 / 5 (2) Aug 10, 2012
Gee I've noticed a dirth of idiotic blathering from climate denialists during the recent spat of news reports on how climate change is making the current weather far worse and far more common.

While facts never meant much to them, perhaps they've realized that they staked out a lose lose position.

If they are right (and they are not) then the world is getting hotter and there is nothing we can do about it.

If they are wrong, then the world is getting hotter, and it will get a lot hotter than it would have if we had changed our ways starting a couple of decades back.

Either way they are set to roast with the rest of us.

So they have little to celebrate really, which makes you wonder what point it was they thought were trying to get across, and to what purpose.

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