This is the first teaching of this course called Paleoclimate. We have a lot to do this semester – we will core a lake, core trees and visit ice cores. The course was formerly Climate Change – you can glance at the previous posts at this site and see the work other past classes. With the issues surrounding Climate Change at the forefront these days, the course takes on a new urgency. I look forward to learning about the past operation of Earth’s climate by examining the paleoclimate records of others and generating our own. We then will examine how these findings are relevant to anticipating our present and future greenhouse world.
Climate Change 2017 is pleased to have been asked to date the Tracy House, Apple Creek Ohio. The log house/cabin is now stored in the soon to be Apple Creek Community Center and Library. The house will be reassembled this coming summer. The date is unambiguous and most of the timber was cut after the growing season of 1826 and it is likely that the house was originally constructed in 1827, one of the first to be built in the East Union Township. A copy of our report can be found here.
Nick gives the crew the rundown.
Graph showing an 100 year overlap between the North East Ohio (NEO) ring-width chronology and the ring-width chronology from the Tracy House. For the full 230 year period of overlap the correlation is 0.75 – pretty impressive, it shows the power of tree-ring dating and the sensitivity of white oak to climate in Ohio. To learn more about the utility of this data view this.
Dean extracts a core from a beam of the Tracy House under the watchful eye of Annette – the TA, as Conner looks on.
Extracting a core being careful to preserve the outer ring of the core (don’t bend the extractor John).
Another successful core extracted.
Special thanks to the Apple Creek Historical Society for working with us on this project.
Below is the group resting after work on a 70 degree F day in February at Browns Lake Bog where they cored some of the remnant old growth oak stands of Northeast Ohio.
Two class projects kick off the Climate Change course. The first deals with tree-ring dating (dendrochronology, blog post coming soon) of historical structures and then analyzing the tree-rings for their climate significance. The second is is shown below and it concerned with analyzing sediment cores that document climate variability since the last Ice Age. Below are some photos of the bog coring – great thanks to Dr. Tom Lowell and his Glacial Geology class from the University of Cincinnati – the folks who did most of the work.
Setting up the coring rig at Browns Lake – early in the day snow covered the ground by 4 pm it was gone.
The core boss (Dr. Tom Lowell) oversees the extraction of another meter of mud from the bog.
The probing team sends down 7 rods through the mud until refusal. Mapping the mud thickness gives an idea of the geometry of the bog and allows for the construction of an isopach map.
Extracting peat – the upper 5 meters or so are peat.
Setting up the production line.
Coring a tree to determine the recruitment time – the hypothesis is that these trees moved into the bog recently (past 200 years) – the first trees here since the Ice Age. This nutrient limited bog was fertilized by wind blown dust during European Settlement allowing these vascular plants to obtain a foothold in the previously sphagnum moss dominated bog.
Hey there is a Wooster student – good job Ben.
Nick samples the bog water for its isotopic composition.
2016 was one of the warmest years since we have been keeping track of global temperatures over the last 150 years. 2017 will be warm as well; in April we will see carbon dioxide levels break an all-time (since humans walked the Earth) high – likely over 410 ppm.
This course is an exploration of climate basics, paleoclimate and contemporary climate change. Understanding how and why climate changes is important for interpreting the past geologic record and evaluating contemporary climate change. After an overview of Earth’s ocean-atmosphere system and energy balance, we will explore Quaternary (last 2 million years) dating methods and techniques of reconstructing past climates through field and lab projects. Students will work with paleoclimate data sets from ocean cores, ice cores, tree-rings, lake cores and corals. Labs will include computer modeling, analysis of time series and field and lab projects extracting lake sediment cores and collecting and processing dendrochronological data.
Preparation questions: For each class you will be required to answer preparation questions – they will be linked to the weekly syllabus. They should be answered before the following class as they are designed to guide the discussion for the next class.
Text books: We will be having readings from a variety of texts, n one text is required however a good one is the The Thinking Person’s Guide to Climate Change by Robert Henson (2015). Some readings throughout the class will be from THE GLACIAL WORLD ACCORDING TO WALLY and THE ROLE OF THE OCEAN IN CLIMATE YESTERDAY, TODAY , AND TOMORROW (available online and at the password protected readings tab)- written by Wally Broecker, a renowned climate scientist from Lamont-Doherty Earth Observatory.
Goals: Climate Change is a Q (quantitative) course thus students will need to generate, manipulate and interpret quantitative data. In addition we will use geologic concepts to solve problems and understand and apply scientific methodology. This course is also field and lab intensive and so students will demonstrate their ability to apply Field/Laboratory skills. As we will be performing original studies of lake and tree-ring proxies in the Wooster region students will be need to demonstrate independence of thought and expression (and also behave properly when we are out on trips). The work in this class will demonstrate integrative thinking by problem solving through multiple approaches. Finally through writing reports and giving class presentations the students will develop their communication skills.
Specific Learning Goals are to deepen your understanding in and to think critically about:
– the fundamentals of the Earth’s climate and how biogeochemical cycles and ocean-atmosphere systems operate and interact.
– how the observational and proxy records of climate change are generated and analyzed.
– the role and significance of natural and anthropogenic (human-caused) forcings on climate and strategies that can mitigate the impact of climate change.
Below are posts from Climate Change 2016 as well as previous Climate Change classes.
A dedicated, select group of geologists, physicists, archaeologists, political scientists, biologists, english and history majors joined forces to learn a bit about Climate Change in the natural laboratory of Northeast Ohio. Here they surround a glacial erratic in Secrest Arboretum of the OARDC – here we have meteorological records extending back to the late 1800s CE and a pretty extensive collection of stands of trees that are used in our climate studies below.
The first project: the glacial transition in a sediment core from Browns Lake Bog
Dr. Lowell gives the rundown at Browns Lake Bog – Tom is a professor at the University of Cincinnati and long-time collaborator and the core boss.
Initial description of the 5 meter core – we obtained two radiocarbon ages, measured magnetic susceptibility, loss on ignition, in addition to core description and sediment analyses.
The Upshot of the Lake Work – The two ages were chosen at transitions in the character of the peat and mineral matter – we identified a major shift at the time of the Bolling – Allerod warming and at the cooling of the Younger Dryas. The abrupt climate changes and discussion of how the world moves from the Pleistocene to the Holocene is brought home to Ohio in this core (Figure below).
Project 2: Tree Ring Dating of the Biggio Barn
The barn owner gives the rundown on the history and possible ages of the hand hewn timber frame. The dating of the barn project introduced the class to the science of tree-rings.
Hong Kong dendrochronologist, Vincent shows the class how by standing on two milk crates he cores a beam – the instructor adds a stabilizing foot to the precarious sampling strategy.
The upshot of Barn Dating: Ten of the beams from the Biggio Barn were cut in the spring of 1840 CE. The building then was likely constructed shortly after that cut date. A copy of the report to the owner from the class can be found here. The ring-width data obtained in this study are used in drought studies below.
Project 3a: Extracting a Temperature Proxy Record from Larch in Kamchatka
Vincent Hui, Abbey Martin, Sarah McGrath, Matthew Shearer, Ann Wilkinson
The purpose of this study was to analyze Kamchatka larch (Larix cajandery Mayr.) tree ring widths from Fareast, Russia. The team standardized the chronology using two methods, (1) negative exponential, and (2) regional curve standardization (RCS), and they then compared how the standardization technique influenced correlations. Both standardized series were correlated with meteorological records showing high positive correlations for summer temperatures. The RCS showed stronger correlations and was used for NTREND comparison, temperature reconstruction, and spectral analysis. Together these correlations and comparisons showed the larch primarily responds to summer temperature and can be used to reconstruct summer temperatures.
The team of researcher (with out Vincent) who did the Kamchatka study at Wooster Memorial Park where a recent planting of 700 trees and prairie will sequester more carbon in the future than the previous agricultural land use.
2 – The team recommends the RCS method for standardization with a sample size of 190 series.
3 – The RCS series showed similar trends as the NTREND series, suggesting the Kamchatka site follows similar trends as the rest of the northern hemisphere.
4 – Ring-widths show a general increase in temperature over the last 350 years for the interior of Kamchatka.
Project 3b: Past climate inferences using data from Johnson Woods
Sharron Osterman, Annette Hilton, Cameron Steckbeck, Gina Malfatti, Amineh AlBashair
- The Johnson Woods team assembled a newly compiled data set originally sampled in 1985 by Dr. Ed Cook (LDEO), by the Wooster Tree Ring Lab in 2003 and most recently updated by Dr. Justin Maxwell (Indiana State University). They found there was a marked release in the tree ring record across northern Ohio about the time of European Settlement in the region. This may be in part due to the disturbance in the record, however it could also persist due to the positive response that tree growth has to summer precipitation.
- Above is a histogram showing the correlations of the Johnson Woods ring-width series and monthly precipitation and temperature records from the OARDC spanning 1880 to 2014 CE.
One Question on the final exam:
What is the Climate response of European Larch to climate of Ohio – Secrest Arboretum (and why might it be relevant?).
Obtaining high quality cores for ring-width chronologies from European Larch at Secrest Arboretum.
The upshot here is the ring-width chronology below. The class worked on this as part of the final exam and found that similar to the oaks in the region, the European Larch is sensitive to summer precipitation and is stressed by high summer temperatures. The tailing off of the ring-widths during recent decades could be the result of warmer summer temperatures – a hypothesis that needs testing. The relevance of this study is that as climate changes in the high latitudes of Europe and Asia, where larch dominates – it may be the case that warming may stress the species leading to decreases in bioproductivity – these ideas need further work to test if this is a viable hypothesis.
A day in Johnson Woods – the full class in the rain.
We also learned that Dan Misinay (’16) is a pretty fair teaching assistant.
The class wanders around the gas power plant on the Wooster campus – two years ago the college transitioned from coal burning to natural gas – the carbon dioxide emissions on campus have been cut in half. However, now the College buys its power for cooling (air conditioning) off campus from the grid, where much of the electricity is powered by coal, but with a growing portfolio of clean energy sources (special thanks to Lanny Whitaker who showed us the plant and explained where our energy comes from – thank you). We also thank Nick Wiesenberg (our able Geology Technician) for his knowledge of trees, barn dating and general troubleshooting, Tom Lowell and his students for the high quality sediment cores, our TA Dan and a host of tree-ring scientists who contributed data to our efforts in this course. A portion of the Kamchatka tree-ring record was supported by NSF- AGS – 1202218.