What is Earth's Correct Temperature?
If earth is currently overheating, then what is earth’s correct temperature? 20,000 years ago, Canada was covered by an ice sheet two miles thick. According to PA’s Dept. of Conservation and Natural Resource’s (DCNR), that same glacier extended to northern PA, and all of PA “…was subjected to a climate that was much colder than what we now experience within the state. Most, if not all, of the ground was frozen to some depth throughout the year in a condition called permafrost.” (see p. 25—emphasis added)
Yet the DCNR publication reminds us that the glacier, present in PA 20,000 years ago, was not the norm, and that earth’s climate is usually much warmer than the cool period earth is now experiencing. The DNCR notes “…that glaciers existed during only a relatively few short epochs of time within the earth’s 4.5 billion or more years of existence. Large glaciations occurred about 600 million and 300 million years ago.” (see p. 1)
Recently (which in geologic time means about 16 million years ago) the earth entered another cooling cycle, beginning the glaciation that eventually climaxed in PA 20,000 years ago. The formation of all that ice consumed “…ocean water enough to cause sea level to drop 300 feet or more. This means that about 18,000 years ago the Atlantic Ocean shoreline of eastern North America was about 60 miles east of its present position.”
The DCNR knows that earth’s temperature moves in cycles; that earth is currently in a COOL period; and that earth has been NATURALLY WARMING (meaning warming without any human influence) for about 18,000 years. Is earth’s “correct” temperature the frozen permafrost; is it today’s warmer temperature; is it okay if earth’s current warming trend continues? Is the “correct” ocean level 300’ lower than today; is today’s ocean level correct; is it okay if earth’s oceans rise, even further, when earth returns to, what the DCNR reminds us, is earth’s “normal” condition…of no glaciers?
The history of glaciers—right here in PA—reminds us that earth’s temperatures change naturally. But apart from natural change, isn’t earth suffering from a record amount of carbon dioxide (CO2) in the atmosphere? That’s a good question. What is earth’s correct CO2 level?
Today’s geologic period (Quaternary) has the LOWEST average CO2 levels in the history of the earth. The average CO2 concentration over the last 600 million years was more than 2,600 parts per million (ppm), nearly 7 times higher than our current concentration of about 400 ppm. And at its highest, earth’s CO2 level was 10 times higher than our current concentration.
You hear the term “climate denier” a lot. Let it be on the record: PGCC does not deny this climate history:
· Earth is still in a cool period that started 16 million years ago;
· Earth’s temperature has been rising for the last 18,000 years;
· Earth’s ocean levels have risen over 300 feet in the last 18,000 years;
· Glaciers on earth are the exception, not the norm; and
· The CO2 concentration in today’s atmosphere is very, very low.