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2019-07-26

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Cool meal: An Amur tiger at a zoo in Chicago, U.S., enjoying an ice treat filled with meat on a summer day.   | Photo Credit: AP

World temperatures rose faster in the late 20th century than at any other time in the last 2,000 years, according to a study released on Wednesday.

Climate variability — the fluctuation of surface temperatures over time — has long been the subject of debate.

While average global temperatures are currently around 1°C hotter than pre-industrial times, there have been a number of periods of cooling and warming over the centuries. This had led sceptics of manmade global warming to suggest that human activity is not the main driver of climate change.

Researchers used data compiled from nearly 700 temperature indicators — tree rings, sediment cores, coral reefs and modern thermometer readings — to provide a comprehensive timeline of the planet’s recent climate history.

The findings are clear: at no point in modern human history did temperatures rise so quickly and so consistently as in the late 20th century — the period where the world’s post-war, fossil fuel-powered economy reached unprecedented heights of production and consumption.

A paper, published in the journal Nature, examined regional temperature trends over time.

A second paper, in Nature Geoscience, examined rates of surface warming, averaged over sub-periods each a few decades long.

The study found that pre-industrial temperature fluctuations were largely driven by volcanic activity.

But it also concluded that humans had never witnessed such rapid global warming as in the latter part of the 20th century.

Commenting on the studies, Mark Maslin, Professor of Climatology at University College London, said their results “should finally stop climate change deniers claiming that the recent observed coherent global warming is part of a natural climate cycle”.

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