Extreme Temperature Diary- December 15th, 2018/ Topic: The Pliocene…CO2 Levels Now Mirror This Past Epoch

Saturday December 15th… Dear Diary. The main purpose of this ongoing post will be to track United States extreme or record temperatures related to climate change. Any reports I see of ETs will be listed below the main topic of the day. I’ll refer to extreme or record temperatures as ETs (not extraterrestrials)😊. 

The Pliocene…CO2 Levels Now Mirror This Past Epoch

Many a climate article in the past decade have compared “current” and “future” CO2 levels to those of past geological times in Earth’s history. I’ve barely touched on the science of paleoclimatology on this site, so I’ll begin delving into that more as we go through time on the Diary. Let’s start by examining just what climate conditions predominated the planet during the Pliocene when CO2 levels were just over 400 parts per million, which is the same concentration that carbon pollution has brought us to as of 2018.

Of most relevance this dystopian article from Grist peaked my interest from this week: https://grist.org/article/welcome-to-the-eocene-where-ice-sheets-turn-into-swamps/

(We will examine the Eocene tomorrow.) Quoting Grist:

Our current rate of warming will quickly lead us back to a climate that predates the evolution of modern humans, according to a new study in the Proceedings of the National Academy of Sciences. That kind of rapid change has no direct comparison in all of Earth’s multi-billion year history.

“The only thing that comes to mind is a meteorite impact,” says co-author Jack Williams, a paleoecologist at the University of Wisconsin-Madison.

The researchers analyzed the current, near-past, and near-future climates for every part of the planet, and then compared them to what likely existed during similar warming periods of the distant past. The results were shocking, even to Williams.

“We are creating a geological-scale climate event,” Williams says. “These things don’t happen that often, and we don’t know how humans will do through it.”

Without rapidly reducing emissions, we’ll quickly go back to a climate similar to somewhere between the Pliocene and Eocene — geological epochs that occurred about 3 million, and about 56 million years ago, respectively. Both would have hellish consequences and likely reshape human civilization permanently.

During the Pliocene period, global temperatures were about 2-4 degrees Celsius warmer than today and sea levels eventually stabilized about 60 feet higher than current levels. It was a world largely inconsistent with natural ice formation.

By 2030, under a business-as-usual scenario, Pliocene-like conditions become the closest match for most land areas, according to the study. Under a moderate climate action scenario, like the lax pledges of the Paris Agreement, that could be extended out to 2040. Only a drastic, economy-wide makeover within the next decade, consistent with limiting warming to 1.5 degrees C, would avoid the transition.

“This is coming up pretty fast,” Williams says.

For my readers who want some education here is how Wikipedia defines the Pliocene, when the earliest hominids started to roam the Earth: https://en.wikipedia.org/wiki/Pliocene

The Pliocene ( /ˈpləˌsn/;[2][3] also Pleiocene[4]) Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58[5] million years BP. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch. Prior to the 2009 revision of the geologic time scale, which placed the four most recent major glaciations entirely within the Pleistocene, the Pliocene also included the Gelasian stage, which lasted from 2.588 to 1.806 million years ago, and is now included in the Pleistocene.[6]

 The global average temperature in the mid-Pliocene (3.3–3 mya) was 2–3 °C higher than today,[11] carbon dioxide levels were the same as today,[12] and global sea level was 25 m higher.[13] The northern hemisphere ice sheet was ephemeral before the onset of extensive glaciation over Greenland that occurred in the late Pliocene around 3 Ma.[14] The formation of an Arctic ice cap is signaled by an abrupt shift in oxygen isotope ratios and ice-rafted cobbles in the North Atlantic and North Pacific ocean beds.[15] Mid-latitude glaciation was probably underway before the end of the epoch. The global cooling that occurred during the Pliocene may have spurred on the disappearance of forests and the spread of grasslands and savannas.[16]

Human evolution during the Pliocene

Pliocene mammals of North America


As noted by the above right chart the first identifiable pre-humans began to roam the planet during the Pliocene. The Earth cooled down enough to allow for human habitation and slow development. Us humans of the current age are beginning to experience a climate not seen since the dawn of man. Will we adapt? Certainly if we can limit warming below +2C above preindustrial conditions according to the best science and experts of this day. The Wikipedia depiction to the left shows how different the fauna was back in the Pliocene 5 to 2.5  million years ago. 

It has often been written that we are living at the dawn of a new age, the Anthropocene, or the age when humans through their activities changed the face of the Earth so abruptly that there will be a distinct geological and fossil division in earth strata. If some beings are around millions of years from now to dig through the Earth it won’t be hard at all to recognize this district time when the use of fossil fuels and human overpopulation changed Earth’s climate and brought many species to extinction. Imagine in the scant time, geologically, of no more than 600 years from say about the year 1500 2100 there has and will be immense change, first through European colonialization and invention, then through industrialization. We are living in strange, horrific but at the same time wonderfully jaw dropping times indeed.


Here is some more weather and climate news from Saturday:

(As usual, this will be a fluid post in which more information gets added during the day as it crosses my radar, crediting all who have put it on-line. Items will be archived on this site for posterity.)

(If you like these posts and my work please contribute via the PayPal widget, which has recently been added to this site. Thanks in advance for any support.) 

The Climate Guy


Leave a Reply

Your email address will not be published. Required fields are marked *