Research breakthrough: CO2 rises caused warming that ended last ice age
Compelling new evidence suggests that rising CO2 caused much of the global warming responsible for ending the last ice age.
The study, published in Nature, confirms what scientists have believed for sometime, and further supports the view that current rises in human-driven CO2 will lead to more global warming.
“CO2 was a big part of bringing the world out of the last Ice Age and it took about 10,000 years to do it,” said Jeremy Shakun from Harvard University and lead-author of the report.
The study found that globally carbon dioxide rises preceded rising tempuratures at the end of the last Ice Age (©23am.com/Creative Commons)
“Now CO2 levels are rising again, but this time an equivalent increase of CO2 has occurred in only about 200 years, and there are clear signs that the planet is already beginning to respond.”
“While many of the details of future climate change remain to be figured out, our study bolsters the consensus view that rising CO2 will lead to more global warming.”
While previous studies only compared carbon dioxide levels to local temperatures in Antarctica, the current study aimed to reconstruct global average temperature changes, using 80 core samples from around the world.
Looking only at local temperatures in Antarctica, warming appears to precede rising CO2, an argument often adopted by sceptics to disprove carbon dioxide’s role in global warming.
Shakun however, says this is leaving a huge gap in the research.
Putting all these records together into a reconstruction of global temperature shows a beautiful correlation with rising CO2 at the end of the Ice Age,” said Shakun. “Even more interesting, while CO2 trails Antarctica warming, it actually precedes global temperature change, which is what you would expect if CO2 is causing warming.”
Most scientists, according to Shakun, now believe the first factor in rising temperatures in Antarctica was not carbon dioxide emissions but a change in the Earth’s orbit, which resulted in more sunlight hitting the northern hemisphere.
As ice sheets over North America and Europe melted, millions of gallons of freshwater flooded into the North Atlantic Ocean and disrupted the cyclical flow of ocean currents.
Atmospheric CO2 compared to Antarctic temperature and global mean temperature at the end of the last ice age (© Jeremy Shakun)
This meant the current which normally brings warm water north from the tropics – and today keeps Europe mild – was blocked, and the Southern Hemisphere warmed at the expense of the Northern Hemisphere – melting Antarctic ice and drawing up CO2 from the deep water.
Shakun says this all points towards CO2 being an amplifier for warming in the Southern Hemisphere.
He said: “If it was an amplifier, the question is how big an amplifier? Does it explain a lot of climate change, or was it a small piece and other factors were more important? I think this research really points a strong finger at the idea that CO2 was a major player.”
While the research strengthens the link between CO2 and the Ice Ages, Shakun believes it also reinforces the importance of addressing CO2 driven climate change today.
Category: Learning
The data show that the antarctic temperature rise preceded the rise of atmospheric CO2. Thus the warmer climate caused the rise of atmospheric CO2 and not the reverse. Other scientists have pointed out this relationship in other data sets. Atmospheric CO2 does not influence climate. Thank you for the proof. Quod Erat Demonstrandum.
Amazing! What a perfect example of the old ‘place fingers in the ears and chant LA LA LA!’ ‘skeptic’ method.
It’s RIGHT THERE in front of you in black and white for heavan’s sake.
“…while CO2 trails Antarctica warming, it actually precedes global temperature change, which is what you would expect if CO2 is causing warming….”
Desperate or what.
Desperate indeed, look closely at the charts and you will see temperatures drop very sharply while the CO2 levels remain high, meaning the warming was mostly caused by other things.
One word – causation. What caused what? Adjusting a graph to show Co2 scaled to temperature differences at Antarctica do not prove that Co2 caused the temperature changes. The temperature changes could very well have caused the Co2 – melting permafrosts, less ice – more wild fires….
And this article implies that Co2 > Temperature causation is linearly scalable to today’s levels? No wonder people are disagreeing more and more, this isn’t science, it’s propoganda.
Actualy, there is near unanimous agreement among scientists.
There is no debate over the basics and hasn’t been for at least 20 years. The only ‘people disagreeing’ these days are those with a political agenda and not the least understanding of climate science.
Yet another…er…”skeptic” meme crumbles before scientific research. What have you got left now? Oh that’s right – “it’s all due to the invisible alien lizard people” and “climate scientists are all in the pay of Marxists”.
Not really credible is it.
Causation is right. This study indicates that some ice cores show CO2 rising before temperature, while other ice cores show CO2 rising after temperature. This makes me question the validity of using ice cores to try to show a causal relationship between temp and CO2. If they all agreed perhaps ice cores are a good source of paleoclimate data, but if they show this much variability I’d say ice cores are unreliable.
I’ve never trusted ice core data and now this study demonstrates that they are not reliable. Thanks for the heads up.
“…I’d say ice cores are unreliable…”
Well, of course you’d say that.
Unless you thought they supported your political agenda and then, of course, they would be rock solid ‘proof’ that ‘climate change is a hoax’.
The…er…”skeptic argument” has always been extremely weak – now you just look desperate.
This has been debunked. Of course the MMGW people have to say C02 rose first because if it didn’t then it couldn’t have caused the warming. This has long been the hole in the MMGW theory. The fact is every Ice-core ever taken shows temps increases fallowed by Co2 increases. hence the reason why MMGW is BS!!!!