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The Little Ice Age is often cited by climate change deniers as proof humans are not causing global warming. The theory goes that Earth is naturally coming out of a period of coolness, and thus the changes in global temperature are merely coincidental.
We’ve known for a while that argument is essentially crap. But now a new study has further cemented its crapness by discovering that the Little Ice Age was almost insignificant, and cannot account for modern temperature increases.
Published in Astronomy and Geophysics, researchers led by the University of Reading examined this supposed period of cooling that’s thought to have taken place intermittently around the world from the 16th to 19th centuries. A decrease in solar activity of the Sun from 1645 to 1715, known as the maunder minimum, is thought to have played a part.
But looking at historical records, including cores of Antarctic ice and paintings from the era, the researchers found little evidence it was that cold at all. This has important implications for the true effect man-made carbon dioxide emissions are having on the climate.
“On the whole, the Little Ice Age was a manageable downturn in climate concentrated in particular regions, even though places like the UK had a larger fraction of cold winters,” said lead author Professor Mike Lockwood in a statement. “Our research suggests that there is no single explanation for this, that warm summers continued much as they do today and that not all winters were cold.”
In particular, they found that the average temperature in the northern hemisphere dropped by just 0.5°C (0.9°F) during the supposed Little Ice Age period. By comparison, the most recent actual ice age 12,000 years ago saw a drop of 8°C (14.4°F).
Frost fairs have also been a key piece of “evidence” supporting the Little Ice Age. In 17th and 18th-century London, the Thames was said to have frozen over on multiple occasions, allowing people to celebrate on the icy river. This stopped in the 19th century, supposedly as the world came out of the Little Ice Age.
But the researchers found the ending of frost fairs had nothing to do with climate change. It was actually the result of an increased river flow, caused by the original London Bridge being demolished in 1825, and the Victoria embankment opening in 1870. Paintings from the era also continued to depict both warm and cool temperatures.
“This study provides little solace for the future, as we face the challenge of global warming,” said Lockwood. “Solar activity appears to be declining at present, but any cooling effect that results will be more than offset by the effect of rising carbon dioxide emissions, and provides us with no excuse for inaction.”
Thames frost fair, by Thomas Wyke in 1683-84. Public Domain
