Yesterday I posted an article saying that the Earth has been warmer than today for hundreds of millions of years. A couple of readers asked how scientists know what the temperature would have been back then, and a reader provided this wonderful explanation. I love her final two sentences.
How do we know what the climate was like hundreds of millions of years ago?
There are one-celled creatures called foraminiferas which have lived in the oceans for about 550 million years. When they die they become buried in the ocean sediments. Recent sediments are of course soft but pressure and heat have hardened older sediments into sedimentary rocks. These strata have been analyzed with microscopes and these one-celled creatures indicate what the climate was like at the time they died since they are sensitive to temperature.
There are thousands of varieties of foraminifera and some varieties need warm temperatures and others can tolerate cold temperatures. SoO paleontologists have been able to document a pretty clear picture of ancient climates.
You will notice that paleontologists are NOT interviewed about “global warming”. No point in injecting a few facts into the debate.