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.
http://www.theregister.co.uk/2012/07/10/global_warming_undermined_by_study_of_climate_change/
The point of science is to attempt to determine truth by designing experiments that would disprove a theory/hypothesis/conjecture. The AGW science of today only rarely allows itself to aim for that outcome.
The conclusion:
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.
And this is one of the questions that current climate science cannot answer, and will not be able to answer for some time. And that question is - what is causing changes in climate? The only scientifically valid way to answer the question is with climate models which demonstrate predictive power and sufficient accuracy. These do not exist.
The other question that climate science cannot answer is - will "we" be better off with warming or not? They guess - they do not know.
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