It’s easy to believe that climate change is a relatively recent phenomena, that is, recent as far as the start of the Industrial Revolution about 150 years ago. But changes in Earth’s climate have occurred before, even millions of years ago. After all, no matter how the carbon accumulates in the atmosphere, the Greenhouse Effect still happens to raise global temperatures. So, in order to discuss more about ancient climate change and their similarities to today, the Perpetual Notion Machine welcomes John “Jack” Williams to the show as our guest.
Jack is a paleoecologist at UW-Madison and tells PNM reporter Dennis Shaffer that despite climate changes, Earth has been through a cycle or consistent pattern of ice ages, the oldest coming about 800,000 years ago. But climate changes have occurred as long ago as 3 million years, during the Pliocene epoch, and 50 million years, during the Eocene epoch. Jack mentions some reasons as to why the Earth warmed significantly during these two periods, such as changes to the Earth’s orbit around the Sun and tilting of the Earth’s axis. In a study published in December, using computer models, analysis shows that current climate temperatures could approach that of the Pliocene by the year 2030. With an amount of about 410 ppm carbon in the atmosphere, the warming is close to 2 degrees Celsius, and the Pliocene had about 3 degrees Celsius. But even more dramatic, the models show that Earth could reach the devastating levels of the Eocene by 2100.
To read the UW-Madison press release of Jack’s study, click here.
To learn how and where paleoecologists find the evidence of climate change, here’s a webpage from the British Geological Survey.
Also, there’s a very good article that describes the climate change during the Pliocene.
And finally, to give you some information about the Eocene climate, check out this Youtube video from the Canadian Museum of Nature.