Paleoclimatic research is providing a more detailed look on how the planet’s average surface temperature fluctuated over the Holocene – the current geological era we are in that began ~12.000 years ago. This is practically the time in which the human species really evolved as a civilization, making its mark on the planet, abandoning the hunter-gatherer traditions to settle down into an agricultural, settlement focused lifestyle.
They used indirect markers, like pollen and shells from marine organisms to chart long time warming and cooling trends. They concluded that the hottest period was during the start of the Holocene, with temperatures in the past decade going close to those numbers, but not quite reaching them – that however, will soon change.
“By the year 2100, we will be beyond anything human society has ever experienced,” said study leader Shaun Marcott, a postdoctoral researcher at Oregon State University’s College of Earth, Ocean and Atmospheric Sciences.
According to NASA, the average global temperature for 2012 was 14.61 degrees Celsius (58.3 degrees Fahrenheit); even an increase of a single degree can have catastrophic consequences – bare in mind, this is the average temperature for the entire year for the entire globe. Basically, every 1.8-degree Fahrenheit increase brings with it a (roughly) 20 meter increase in sea levels – but that’s really the least of the problems. In the past century, temperatures have risen by 1.3 degrees, and the trend is accelerating
This research, which was published in Science, was not the first one to reach this kind of conclusion using such proxies, but it is first to pull together so many of them from all over the world, clearly indicating the rate and magnitude of global warming:
“We know that there were periods in the past that were warmer than today — for example, the Cretaceous period 100 million years ago,” said Michael Mann, a physicist and climatologist at Pennsylvania State University. “The real issue is the rate of change, because that’s what challenges our adaptive capacity.”