Enlarge / The ice age weather (left) gave way to one that slowly warmed until industrial times. (credit: Matthew Osman)
The climate “hockey stick” refers to a reconstruction of temperatures over the past 1, 000 years. The data shows flattish temperatures over the last millennium , like the handle of a Hockey stick, ending in a “blade” of rapidly rising temperatures since the particular industrial revolution. The idea first appeared in a paper by Michael Mann and Raymond Bradley of the University of Massachusetts and Malcolm Hughes of typically the University of Arizona. The work became famous after appearing in a UN climate report, after which it was the focus of climate denial, hacking , defamation , and disinformation, all of which was dramatized in a recent BBC TV drama called “ The Trick . ”
Today, in a paper published simply by Nature, scientists show that this “handle” of the “hockey stick” extends back 9, 500 years, while its “blade” is taller—the last decade was 1. 5° C hotter than the average temperature over the last 11, 700 years. “Human-caused global temperature change during the last century was likely faster than any changes during often the last 24, 000 years, ” said lead author Dr. Matt Osman of the University associated with Arizona.
An animation showing the warming that ended the last ice age. (credit: Matthew Osman)
Taking your temperature of times before thermometers
To measure temps at times long before the invention of thermometers, scientists must use indirect proxies. For the new study, scientists carefully vetted over 500 proxy records from oceans around the world; the data shows the fossilized remains regarding plankton and microbes in sediments where the age is known from radiocarbon dating.
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