With 2015 standing as the hottest year to date—surpassing records less than 365 days old—one might think that global temperatures are rising at unprecedented rates, but research published in the latest edition of the journal Nature Communications suggests otherwise.
The study, led by scientists at Friedrich-Alexander-Universität Erlangen-Nürnberg in Germany, reported that the temperature changes that took place millions of years ago likely occurred at the same rate as today’s warming, and that the speed of past warming tends to be underestimated.
As study authors Dr. Wolfgang Kießling, a paleobiologist from FAU, his colleague geosciences student Kilian Eichenseer and David B. Kemp from the Open University’s Environment, Earth and Ecosystems Department explained, climate scientists study the impact of historical climate change as a way to predict how modern ecosystems will react to similar warming.
Previously, the general consensus has been that modern-day climate change is happening more quickly than at any point in the past, but the researchers explained that this is a false assumption based on the comparison of shorter modern-day periods to longer historical time spans.
Like comparing apples to oranges
“Today we can measure the smallest fluctuations in climate whenever they occur. Yet when we look at geological history, we’re lucky if we can determine a change in climate over a period of ten thousand years,” Eichenseer explained in a statement.
Case in point: From 1960 through 2010, ocean temperatures increased by a rate of 0.007 degrees per year, Dr. Kießling said. That’s 42 times faster than it increased 250 million years ago during the Permian-Triassic boundary. The temperature of the ocean increased by 10 degrees during that time, he explained, but since scientists can only measure over a 6,000 year period, it equates to a seemingly low rate of just 0.00017 degrees per year.
In their new study, the authors reviewed about 200 analyses of climate changes from different eras in geological history, and found that the rate of warming (or cooling) appears to slow down in correlation with the length of the time period being evaluated. The reason for this, they said, is that rapid changes in climate do not consistently occur in the same direction over a long period of time, and that there are always times when temperatures remain constant.
“However, we are unable to prove such fast fluctuations during past periods of climate change with the available methods of analysis,” Dr. Kießling said. “As a consequence, the data leads us to believe that climate change was always much slower in geological history than it is today, even when the greatest catastrophes occurred. However, that is not the case.”
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Feature Image: Thinkstock
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