We will now turn our attention toward the evolution of Earth's atmosphere and ocean system through geologic time, specifically focusing on our understanding of paleoclimatology (ancient climates). We will consider potential lessons from this knowledge of ancient climate under so-called greenhouse and icehouse conditions. In particular, I will ask you to consider how this knowledge can aid our predictions of, and planning for, future climate change.
Lesson 4 will take us one week to complete. As you work your way through these online materials for Lesson 3, you will encounter additional reading assignments and hands-on exercises and activities. The chart below provides an overview of the requirements for Lesson 4. For assignment details, refer to the lesson page noted.
Please refer to the Calendar in Canvas for specific time frames and due dates.
ACTIVITY | LOCATION | SUBMISSION INFORMATION |
---|---|---|
Short (2–3 page) paper on "Exploring the links between paleoclimatology, the Critical Zone, and modern society" | page 4 | Post to the Lesson 4 - Paleoclimatology Activity dropbox in Canvas |
If you have any questions, please post them to our Questions? discussion forum (not e-mail), located under the Discussions tab in Canvas. I will check that discussion forum daily to respond. While you are there, feel free to post your own responses if you, too, are able to help out a classmate.
Paleoclimatology, the study of ancient climates, has become increasingly recognized as a socially relevant tool for unraveling the causes and consequences of ongoing and future climate change. Scientists use the knowledge and insight gained from reconstructing ancient episodes of climate change to better understand how Earth's future climate may behave during climate states not experienced during recorded human history. In addition, a complete understanding of natural climate variability allows us to better identify and understand the role of human activity on climate change. For example, we know that ancient episodes of warmth have occurred in which crocodile-like reptiles and subtropical forests thrived throughout the high arctic. During these times, the atmospheric hydrologic cycle was amplified, the quantity of precipitation was elevated and more broadly distributed, and weathering and soil formation were intensified with tropical soil-forming conditions extending into the mid- to high-latitude regions of the planet.
Tim and colleagues are working to reconstruct one such interval in Earth history the Paleocene-Eocene Thermal Maximum.
To begin to understand the ties between this work and the carbon cycle, view this video from Svalbard.
(Where is Svalbard? [2])
The record of paleoclimate variation in Pennsylvania includes very ancient paleosols formed during episodes of tropical climate conditions to the more recent deposits of vast ice sheets that extended far to the north into Canada. To learn more view the following video.
Before we delve into the specifics of paleoclimatology, I want you to understand current views on the evolution of Earth's atmosphere and ocean system. Much of this information is highly theoretical, based on scant geologic evidence from the very distant past and computer models. However, this information will provide you with a baseline comprehension of natural variations in Earth's climate, for comparison to human-induced (or anthropogenic) causes of climate change.
I also want you to understand how politics can influence science. Some of the links below, specifically those from the US Environmental Protection Agency for Past and Recent Climate Change, are archived and not easily available - this is a function of a different attitude toward climate change research from our current president and his admininstration. Thus, I have provided other links to similar material though I encourage you to explore the EPA links anyway.
In this assignment, you will begin to explore the links between paleoclimatology, the Critical Zone, and modern society.
Next, carefully study the map below, then learn more about laterites [15]. Mid-Cretaceous refers to a broad expanse of geologic time from ~120,000,000 to 85,000,000 years ago, when the planet was generally much warmer than today with, for example, dinosaurs stomping around in sub-tropical forests near both poles. As you read about laterites you may want to refer back to knowledge gained in our lesson on soils and soil orders, specifically the geographic distribution of oxisols.
L4_paleoclimatology_AccessAccountID_LastName.doc (or .pdf).
For example, student Elvis Aaron Presley's file would be named "L4_paleoclimatology _eap1_presley.doc"—this naming convention is important, as it will help me make sure I match each submission up with the right student!
Upload your paper to the "Lesson 4 - Paleoclimatology Activity" dropbox in Canvas (see the Modules tab) by the due date indicated on our Canvas calendar.
You will be graded on the quality of your writing. You should not simply write responses to the questions and submit them to me. Instead plan on writing a short stand-alone paragraph (or page or whatever you decide is necessary considering any constraints I might have placed on you) so that anyone can read what you've written and understood it. You should strive to be specific and complete in responding to the questions. Your answers should be analytic, thoughtful and insightful, and should provide an insightful connection between ideas. The writing should be tight and crisp with varied sentence structure and a serious, professional tone.
Those of us fortunate enough to have experienced Earth sciences in primary and secondary school probably learned about gradual climate change through geologic time, such as the gradual waxing and waning of continental-scale ice sheets during the last ice age. This view of paleoclimate change is appropriate in the context of Earth history and geologic time. However, more recently, paleoclimatologists have gathered evidence for widespread abrupt changes in climate that occurred in the not-too-distant past, on time-scales equivalent to a human lifetime. For those who are attentive to these issues, this realization has served as a "wake-up call" to action—humanity's effect on atmospheric composition and climate change may push the climate system toward a "tipping point" from which rapid regional and global changes in climate of unknown magnitude and duration may occur. The question remains whether human action to reduce greenhouse gas emissions can avert such events.
Read the following text chapter:
The first few pages of the chapter provide a brief overview of paleoclimate proxy interpretations, information you should now be familiar with and therefore can skip here if you choose. Pay particular attention to the discussion of the Younger Dryas, the most recent widespread episode of abrupt climate change for which abundant, globally distributed terrestrial and marine data has been collected.
The concepts and terminology through this portion of the chapter should mostly be familiar to you.
When you reach the sections entitled "Patterns of Climate Variability" and "Trends Recorded Instrumentally," you may find that the terminology is unfamiliar—do not fret. Your primary focus through this portion of the chapter should be to understand that human records of recent-past climate change do exist and provide evidence for and are relevant to our understanding of ongoing and future climate change. Also, read the final section entitled "Synopsis of Observations."
To properly understand and plan for the potential range of variability in Earth's future climate and its effects on the Critical Zone, we must look to the ancient past to understand that Earth's climate has experienced extremes in climate, cold and warm, outside of the span of human history. You just read a lot about paleoclimatology, learned about various government agencies that are interested in paleoclimatology, and viewed maps of glacial and extremely warm greenhouse deposits of the past to consider what socially relevant information might be gleaned from those distributions.
As you shift your attention toward Lesson 5, you should feel comfortable describing: basic concepts of paleoclimatology and the type of information that can be collected to reconstruct ancient climates; Federal agencies with ongoing research in paleoclimatology; examples of paleoclimatologic information that may be relevant to your life and society; and issues regarding the rate of climate change and what we know about the potential abruptness of climate change. In Lesson 5, we will complete Unit 3 by studying regional climate change and taking a more focused look at links between atmospheric processes and the Critical Zone.
You have reached the end of Lesson 4! Double-check the list of requirements on the Lesson 4 Overview page to make sure you have completed all of the activities listed there.
If you have anything you'd like to comment on or add to, the lesson materials, feel free to share your thoughts with Tim. For example, what did you have the most trouble with in this lesson? Was there anything useful here that you'd like to try in your own classroom?
Links
[1] http://www.livescience.com/4180-sahara-desert-lush-populated.html
[2] http://en.wikipedia.org/wiki/Svalbard
[3] http://www.pbslearningmedia.org/resource/tdc02.sci.life.cell.stetteroxygen/life-before-oxygen/
[4] http://www.ncdc.noaa.gov/paleo/paleo.html
[5] http://www.epa.gov/climatechange/science/pastcc.html
[6] https://climate.nasa.gov/evidence/
[7] http://www.epa.gov/climatechange/science/recentcc.html
[8] https://19january2017snapshot.epa.gov/climate-research_.html
[9] http://www.pbslearningmedia.org/resource/ess05.sci.ess.earthsys.esglaciers/earth-system-ice-and-global-warming/
[10] https://e-education.psu.edu/earth530/node/1649
[11] http://www.teachersdomain.org/resource/ess05.sci.ess.earthsys.glaciers/
[12] http://www.pbslearningmedia.org/resource/ipy07.sci.ess.earthsys.glacierphoto/documenting-glacial-change/
[13] http://www.teachersdomain.org/resources/ipy07/sci/ess/earthsys/glacierphoto/index.html
[14] http://www.dcnr.pa.gov/Geology/GeologyOfPA/GlacialGeology/Pages/default.aspx
[15] http://en.wikipedia.org/wiki/Laterite
[16] http://books.nap.edu/openbook.php?record_id=10136&page=19