Climate was HOTTER in Roman, medieval times than now: Study
IPCC has got it all wrong, say boffins
Posted in Energy, 10th July 2012 11:44 GMT
Americans sweltering in the recent record-breaking heatwave may not
believe it - but it seems that our ancestors suffered through much
hotter summers in times gone by, several of them within the last 2,000
years.
Phew, what a scorcher, Marcus. Let's get in the frigidarium
A new study measuring temperatures over the past two millennia has
concluded that in fact the temperatures seen in the last decade are far
from being the hottest in history.
A large team of scientists making a comprehensive study of data
from tree rings say that in fact global temperatures have been on a
falling trend for the past 2,000 years and they have often been
noticeably higher than they are today - despite the absence of any
significant amounts of human-released carbon dioxide in the atmosphere
back then.
"We found that previous estimates of historical temperatures during
the Roman era and the Middle Ages were too low," says Professor-Doktor
Jan Esper of the Johannes Gutenberg-Universität Mainz, one of the
scientists leading the study. "Such findings are also significant with
regard to climate policy."
They certainly are, as it is a central plank of climate policy
worldwide that the current temperatures are the highest ever seen for
many millennia, and that this results from rising levels of atmospheric
CO2 emitted by human activities such as industry, transport etc.
If it is the case that actually the climate has often been warmer without any significant CO2 emissions having taken place - suggesting that CO2 emissions simply aren't that important - the case for huge efforts to cut those emissions largely disappears.
Needless to say, prominent alarmist scientists and the UN's
Intergovernmental Panel on Climate Change (IPCC) have not taken this
view, arguing instead that the well-documented Roman and medieval warm
periods may have taken place but either weren't very warm or only
happened in limited regions (though this latter idea has lately been seriously undermined by research in Antarctica).
In the IPCC view, the planet was cooler during Roman times and the
medieval warm spell. Overall the temperature is headed up - perhaps
wildly up, according to the famous/infamous "hockey stick" graph.
The new study indicates that that's quite wrong, with the current
warming less serious than the Romans and others since have seen - and
the overall trend actually down by a noticeable 0.3°C per millennium,
which the scientists believe is probably down to gradual long-term
shifts in the position of the Sun and the Earth's path around it.
"This figure we calculated may not seem particularly significant,"
says Esper. "However, it is also not negligible when compared to global
warming, which up to now has been less than 1°C. Our results suggest
that the large-scale climate reconstruction shown by the
Intergovernmental Panel on Climate Change (IPCC) likely underestimate
this long-term cooling trend over the past few millennia."
According to the scientists' new paper, published in hefty climate journal Nature Climate Change,
the cooling effect of orbital shifting on the climate has been up to
four times as powerful as anthropogenic (human-caused) warming
pressures. ®
Hope you are all trying to keep cool - the family pets needn't be out. I will be up to speed soon - I'm editing 1200 photos from my trip. Too bad that Glacier is a World Heritage site. Darn! I should've exercised my First Amendment rights to some Canadian or Aussie by discussing politics.
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