Hot earth people and climate change

Hot earth people and climate change

Week 1 – June 22nd

Announcements

Be sure you explore the course Canvas page so you know were all course materials are located.

Contact me via email at lstachowiak@ewu.edu or via Canvas messenger.

As I’m sure you’ve heard from your professors before, we get a lot of emails haha. If you don’t get a response from me with 72 hours, don’t hesitate to send me another message. Your first message may have gotten lost in my inbox so no worries on checking in for an update! 

Discussion #1 is this week

Lecture Outline

Introduction to geologic time (deep time)

The Anthropocene – what is it and when did it start?

Indisputable data sources that show change

Opinions and Misunderstandings

Readings With Lecture

Week 1 Readings:

Syllabus and term schedule

Browse through Chps. 1 & 2 in your textbook.

Notice that each chapter has suggested readings at the end and activities you can work through with data. These are great resources for further learning if climate science is a passion!

Climate change isn’t just a global threat – it’s a public health emergency Adrienne Hollis (2019)

link here: https://time.com/5672636/climate-change-public-health/

And we’re off! Let’s start with concepts of deep time and the Geologic Time Scale…

Geologic Time Scale

The Quaternary

Roughly last 2.5 million years

MOST of the Quaternary was the Pleistocene

last ~10-12K years is Holocene

We are now in what is called the anthropocene

How do we track geologic time?

Two main criteria:

Clear evidence for the transition in strat record

Geographically extensive (can be found everywhere)

The Anthropocene

Anthro- prefix means “of human origin”

This is the epoch of humans — in essence, the human population has increased to such a size, and humans individually have such large ecological footprints, that it is now virtually impossible to find a place on Earth not touched by humans.

This is truly shocking when you think no other species in the history of the Earth (that we know of) has ever had such an impact…

The Anthropocene

Comprehension and Critical Thinking Break!

What are some lines of evidence you think are strongest in support of the end of the Holocene and the beginning of the Anthropocene?

What are some things humans have done to permanently and pervasively impact Earth?

Want to discuss these with me? Just give a shout!

Evidence for The Anthropocene

Check out this series of graphs that shows increases in various metrics through the end of the 20th century. The “great acceleration” is a common theme in ecological studies related to human impacts on the environment.

Evidence for The Anthropocene

Here are additional examples. Check out the graph on radioactive fallout! To me, this is one of the strongest lines of evidence for the presence of the Anthropocene. Radioactive fallout from the mid 1900s can be found in soil all over the Earth.

What does it mean?

Global-scale impacts by humans have been great enough to designate a new epoch in geologic history

Change in dynamical systems can lead to feedback loops. Research what these are if you are unfamiliar…

Indisputable Data for Climate Change

Sea level is rising due to global ice melt

Atmospheric and sea surface temperatures are increasing each year

Wildfire activity is increasing due to increasing aridity and changing local climate dynamics

Ecosystem changes occur each year, sometimes in ways without analogs to the past

Atmospheric Carbon Dioxide

The Keeling Curve

408.5 ppm

Opinion often trumps science

Personal experiences often dilutes facts

Weather is OFTEN confused with climate

Climate Data

Critical Thinking and Comprehension Check!

So what gives? What are some reasons you can think of that prevent progress on climate action?

What might be some misconceptions that people have that contribute to a lack of understanding?

Links to Check Out!

The Keeling Curve in real time

The Keeling Curve

Intergovernmental Panel on Climate Change

Home Page

350.org Climate Reform

https://350.org/

Intersectional Environmentalism

https://www.intersectionalenvironmentalist.com/

NAACP Environmental and Climate Justice

Environmental & Climate Justice

Looking Ahead…

Next week we’ll dig deeper into the differences between weather and climate

You’ll gain exposure on different types of weather and climate observations

You’ll learn how to plot weather data for certain dates in history using a well-known meteorology and climatology website.

Carbon CYCLE

Week 4 – July 13th, 2020

Announcements

Discussion #2 this week on Canvas Discussion Board

Exam #1 Due Sunday by midnight

Lecture Outline

Overview of Carbon Cycle

The Carbon Cycle in the Anthropocene

Focus on carbon in oceans and air (atmosphere)

Note about textbook here – the book discusses things like ocean storage and acidification. We’re swinging back around to these topics in more detail later in the term when we get to the NCA. Please feel free to read them now, but they’re not part of this week’s materials!

Readings With Lecture

Week 4 Readings Include:

Chp. 5 in textbook

Review all previous readings as necessary as you complete your Exam this week

You’ll notice this week’s set of slides is light. That’s because it’s an Exam week and I don’t want to burden you with too much information in the same week. If you’re interested in learning more about the carbon cycle in more detail, as always, don’t hesitate to reach out!

…….

…..and we’re off! Let’s start out with a couple figures that help visualize the carbon cycle. As you’ll notice…there’s lots of ins and outs…

The Carbon Cycle

Here’s a detailed visualization of the cycle that has values to help track the flux of carbon around Earth.

The graph on the next slide is similar, but shows proportions rather than direct values.

The Carbon Cycle

Carbon in the Ocean

The ocean is the largest carbon “sink” or reservoir, above land and air

Storage in ocean can be hundreds to thousands of years depending on depth and incorporation (i.e. does it become part of a fossil that sticks around for millennia?)

Carbon in the Ocean

Deep depths contain the most carbon as it falls to the ocean floor through time, decay, and gravity

I had a professor in my undergrad call it “the rain of corpses and feces,” which while graphic, is accurate! Everything sinks to the bottom or gets swept up in currents if it floats.

Carbon in the Ocean

As previously stated, we’ll get back to ocean acidification and start discussing things like ocean circulation changes later in the term

However, ocean acidification is a problem and I’ll bring it up here quickly…

Carbon in the Ocean

Warmer oceans and more carbon dioxide in the atmosphere (from various sources) leads to two things

Liquids cannot hold as much dissolved oxygen when they are warmer

Atmospheric carbon dioxide is exchanged at the ocean-air interface, such that the upper layers of the ocean are suddenly becoming rich in dissolved carbon

Chemical reactions with seawater lead to build up of carbonic acid (bicarbonate) in oceanwater

Thus…oceans are getting acidic!

Carbon in the Air

Lots going on in this graph, but the one to focus on for that atmosphere is the red Mauna Loa dataset (Keeling Curve!)

Carbon in the Air

We can track carbon dioxide emissions various ways, but two of the common ways is by source (e.g. country) and industry type (e.g. transportation, cement production, etc)

Check out this graph on country contributions of CO2 emissions in gigatons/year!

Carbon in the Air

Here’s another graph from your textbook that shows by industry type

Did you know cement production contributed so much to carbon dioxide emissions?

Carbon in the Air

Here’s another one that’s broken up by country to show usage per person per year.

What do you notice about the US? Eeeks…

Carbon Cycling

Ultimately, carbon cycles. It moves from atmosphere to ocean to land over many, many years

Where it stays impacts the chemistry of the medium

It makes oceans acidic

It causes air to hold energy better, like a blanket rather than a net (more on that in Chp. 6)

It changes even foodwebs! – I teach GEOG/BIOL 306 in the spring terms and we talk about biogeography in the Anthropocene! 

Ok you now have the basics of carbon cycling and how it’s stored in various places on Earth

Take some time to quickly check out the links on the next slide if you’re interested in learning more about carbon and carbon cycling!

Links to Check out!

Carbon Footprint Calculator

https://www.carbonfootprint.com/calculator.aspx

350.org; international organization focused on lowering atmospheric carbon

https://350.org/

Global Carbon Project (mentioned in your textbook!)

https://www.globalcarbonproject.org/

Looking Ahead…

In Week 5 we’ll look at energy flow and Earth’s energy budget

We’ll explore various aspects of the atmosphere, with specific focus on building knowledge of atmospheric circulation

This is generally review for those who have taken GEOG 100, but can be a bit technical for those who haven’t. Don’t hesitate to reach out if you’re ever stuck on something!

Weather vs climate

Week 2 – June 29th

Announcements

Lab #1 is this week

Lecture Outline

Geography in the News – Hurricane Lorenzo, 2019

Basic intro to weather

Basic intro to climate

Weather vs climate

NCEI Explorer primer

Readings With Lecture

Week 2 Readings

Chp. 1-2 in textbook

Lost Cities and Climate Change Kate Marvel (2019)

PDF is on Canvas (Files > Reading Materials > Marvel_2019)

And we’re off! Let’s start with the story of Hurricane Lorenzo, a category 5, from last year…

Hurricane Lorenzo

Reached Cat 5 status Saturday, Oct 5th, 2019

Highest sustained winds were ~165 mph

What made this one unique? Put another way, how many Category 5 hurricanes do you hear hitting the UK?

This storm got massive fast, blew east of the Bermuda High pressure cell which sits in the middle of the Atlantic, and then pushed northeast. Yikes!

Hurricane Lorenzo

This hurricane was the fastest hurricane in recorded history to achieve Cat 5 status (it’s the blue dot among the red dots on the map below)

This hurricane was evidence of exceedingly high sea surface temperatures in the Atlantic Ocean – we can expect similar occurrences in the future…

Hurricane Lorenzo

Hurricane Lorenzo ended up decaying rapidly in strength as it moved out of warm tropical ocean waters. It arrived on the other side of the Atlantic as a minor storm.

Weather

Short-term phenomena occurring in a generally localized region

No “weather of the Earth”

Results from the interaction and activity of atmospheric particles and solar energy

Metrics include temperature, precipitation, relative humidity, wind (speed and direction, etc)

Weather

Think of the atmosphere as a fluid

Weather forecasting is modeling and predicting the activity of the atmosphere over time

Stochasticity in the nature of atmosphere molecules (imagine the chaos!)

Short-term predictions as of right now…

Weather

This is a common weather report for Cheney, WA from the National Weather Service.

Climate

Statistical perspective on weather – what weather ”looks” like over time

NOAA and NWS use baseline climatology of 30 years, usually 1950-80.

In some cases easier to predict than weather (exceptions to this…)

Variations in weather metrics can be tracked spatially AND temporally to create climate histories…

Weather vs. Climate

Common misconception with climate change is that if anything cold-weather related happens, climate change is a hoax…

Follow the logic:

Warmer air holds more moisture (think a hot attic in the peak of summer!)

A warmer atmosphere will hold more moisture, which can fall in a storm even if that storm happens in below freezing temps.

Global warming can easily lead to wetter, snowier storms!

NCEI Explorer

May 2020 U.S. Climate Assessment: https://www.ncei.noaa.gov/news/national-climate-202005

May 2020 Global State of the Climate: https://www.ncdc.noaa.gov/sotc/global/202005

What are some trends you notice? Specifically, do you notice variability across space? Upward trends in global temperature? Changes to precip? How do the US report and global report differ? How might these differences confound positive progress in climate action?

Links to Check Out!

Dr. Ayana Elizabeth Johnson’s media

https://www.ayanaelizabeth.com/

https://www.oceancollectiv.co/

https://urbanoceanlab.org/

The Keeling Curve – check out the different time scales you can look at!

The Keeling Curve

Links page for educational resources related to weather and climate

https://l-zone.info/2015/07/top-10-educational-resources-for-learning-about-the-weather-and-climate/

Looking Ahead…

Next week we begin our discussions of paleoclimates, or climates and environments of the distant past.

We’ll return to the NCEI website for more exploration

You’ll learn how trees record climate data over hundreds of years (even millenia!), and how climate scientists use tree rings to reconstruct climates of the distant past.

Paleoclimates

Week 3 – July 6th

Announcements

Lab #2 is this week

Lecture Outline

Intro to Paleoclimates

Climate variability of the Holocene to now

Climate Proxies

A focus on dendrochronology

Readings With Lecture

Week 3 Readings Include:

Chp. 3 in textbook

Lost Cities and Climate Change Kate Marvel (2019) if you haven’t done so already

The Scientific Consensus on Climate Change Naomi Oreskes (2004) – PDF on Canvas

Environmental Justice, Fossil Fuels, and Telecoms Ayate Temsamani (2018) – link here: https://www.greenamerica.org/environmental-justice-fossil-fuels-telecoms

To Save Climate, Look to the Oceans Ayana Elizabeth Johnson (2020) – PDF on Canvas

And we’re off! Let’s start out with an introduction to what paleoclimates are and how we get the data!

Introduction to Paleoclimates

Research on paleoclimates, or climates of the distant past, answers questions including:

What was the climate of the past like?

When we say “the past,” when do we mean, and how has it changed into the future?

A word up front: Paleoclimates can be discussed at various scales and over various periods…for this class we’ll be focusing on the most recent 10K-20K years or so and onward, with specific focus on the Holocene…we may delve a little bit farther back if time permits…

Climate Variability

Climate is always changing, it’s never static

Using baseline climatology we can establish average climate variables (e.g. temp and precip) for an area

These averages are then used to evaluate and track climate anomalies. These are very important to climate research because anomalies show you deviation from the norm. Thus, we can say things like “the average global temperature in 2019 was warmer than normal.” We know it’s warmer because we have the baseline.

“Fun” fact – if you are younger than 32 years old, you have never experienced a cooler than normal month. Each month you have ever lived through has been as warm or warmer than the 1950-1980 baseline average.

Climate Variability of last 2000 years

Over the past 2K years Earth’s climate first transitioned from a moderate/mild regime during the Medival Warm Period (MWP) in the 800-1200s, to the cold period of the Little Ice Age (LIA) in the 1500-1800s.

However, spatial extent of these two climate regimes/events was not global

Current warming is both spatially extensive, but also occurring at a rate not seen in the proxy record we have

Notice this temperature reconstruction is based on various proxies, not just tree rings.

Side note – the PAGES 2k reconstruction referred to here and in your textbook is newly published. Check out the link to a commentary by Scott St. George, a dendrochronologist at the University of Minnesorta on the research publication at the end of the powerpoint if you’re interested in learning more!

Climate Variability of the Holocene

In general the Earth was warmer in the earlier parts of the Holocene (8000-6000 BC), but has since shown a cooling trend.

However, recent trends show rapid warming – yep, that’s right, the Earth has been in a cool phase compared to longer records.

You can really see the influence of humans on this graph

Need more evidence? Check out the CO2 graph on the next slide…

9

Carbon Dioxide Variability of the Holocene

Here’s a graph from your textbook

You can also check out the Scripp’s data for the Keeling Curve to look at this as well (check back to Lab #1 if you need a refresher on The Keeling Curve!)

Milankovitch Cycles

Cycles in the precession, obliquity/tilt, and eccentricity of Earth’s orbit dictate the amount of insolation receipt at the surface

When these three cycles align such that northern hemisphere summers receive maximum insolation, glaciers retreat and ice ages phase out (and vice versa)

This occurs because snow melt from previous winter is lost during max insolation periods, thus no snow can accumulate and the ice sheets recede/retreat

Read more in your textbook on how these cycles impact ice ages for more information

Critical Learning and Comprehension Check!

Use the CO2 graph provided or one you acquire on your own from the Scripp’s Institute to explain the temperature graph. In other words, how does increased CO2 lead to increased temps?

What do you notice about the rate of temperature change? How does it compare to rates of temperature change in the past?

What additional picture does the Holocene temperature reconstruction provide that the one for the past 2000 years does not? In other words, how does the window with which you look at past climates matter in the current discussion of climate change?

Remember, if you ever want to discuss these with me, don’t hesitate to reach out! I will happily provide you with answers and further resources for these questions if you’re interested!

So we know the climate changes, and we know that it hasn’t changed the same in all places through time.

How do we track these changes? What are climate data and how do we get them?

Let’s go!

Where do we get climate data?

Historical weather records (NOAA for past ~120 years) are great sources of climatological and meteorological data.

Ship logs and the like can get you back a few hundred years, but nothing reliable too far after that

Check out this port log of Philadelphia in 1776. It has date, hour, and temp – neat right!?

Proxy Records of Past Climates

Tracking records of climate change over much longer time periods and farther back in time, we use proxy records

Proxies must reflect appropriate levels of temporal resolution AND depth

In other words, ideal proxies extend far back in time (depth), and have fine temporal resolution to give indications of change through time (e.g. trees form rings each year, thus tree rings provide fine temporal resolution as proxies)

What makes a good proxy?

Consistent relationships between physiological, ecological, geological, etc phenomena and proxy metric over space and time

Ability to track change – again referring to temporal resolution and depth

The more information extracted from the proxy the better…

Tree Rings

Tree rings can give you information on all of the following kinds of environmental signals you may be interested in, such as….

Rainfall

Temperature

ENSO, PDO, AMO

Wildfires

Volcanic Eruptions

Landslides

…

Here’s a picture of a slash pine cross section from a Big Pine Key, Florida in the Florida Keys. This sample was part of my PhD research focused on fire activity through time. The rings are almost hypnotic, no? 

Tree-Rings

Tree rings can provide environmental data for the area they grew in 100s to 1000 years back into the past.

And because trees produce one ring per year, they have annual temporal resolution

In other words, anything that happens to the tree that year will be recorded in the ring. For example, let’s say a fire sweeps through an area in 1558, long before people were keeping records of fire for the area. The fire will produce a scar in the 1958 tree ring on the trees it harms. Then, over 450 years later, a dendrochronologists like me comes along and collets the data!

So how do trees grow and how are rings formed?

What do the characteristics of the tree rings tell us?

Trees grow like stacked cones, each new year brings a new “cone” or ring.

The oldest “cones” will be nearest the base, that’s where we sample!

Width variability = Climate!

1407

1396

Here’s a picture of tree rings up close…

Notice the 1407 ring is exceptionally narrow, and the 1396 ring is wide. This variability is a climate signal through time!

If you collect tree cores from across a region, you now have climate variability through time and space! Wicked cool, no!?

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Tree Rings Up Close!

What do you notice from this collection of six tree cores taken from a forest in Colorado? Look at the 1690s…each decade or so during the 1690s (the rings growing to the left of the 1700 marker on each tree core) is suppressed.

This suppression across the cores indicates a regional response to drought – these trees recorded drought in the 1690s, long before people were keeping records for the area!

Tree Rings

Patterns in ring width can be translated into records of wet and dry periods in past climate

Tree Ring Data

The only proxy with consistent annual resolution – trees grow one ring per year

Trees are found virtually everywhere

Here I am cheesing with a slash pine sample I just cut. It’s kind of hard to see, but my fingers are wrapped around fire scars, which track instances of fire occurrence through time. The tree forms a ring, the fire occurs and leaves a scar in that ring, and BOOM, I can come along and tell you when a past fire occurred down to the year! This is powerful stuff when you want to reconstruct past environments or climates for time periods before record keeping began.

Why might we care about how wildfires acted or “behaved” in the past? Why might it be helpful to know how often, and how severe wildfires were, compared to how they are now?

24

Geoviz – Preliminary Research in Action!

If you’ll indulge my nerdiness here for a second, what you’re looking at is results fresh from my lab. Specifically, students and myself collected Ponderosa pine tree cores from the Cheney wetlands. We then used the wide and narrow variability in ring widths to reconstruct precipitation back 400 years! Any period above the baseline average is green and indicates a wet period, any period below the baseline average is in red and indicates dry periods. The vertical black line on the graph is the beginning of historical (weather) records for the area. Everything before that in time has been reconstructed from tree rings.

These data are fresh, they are still being processed for errors, so this isn’t final by any means. BUT, given these preliminary results, what are some patterns you notice?

Interested? Who wouldn’t be?!

Geography minor = 15 credits

You’re 1/3 done after this class already, and the remaining 2 classes are offered online in the Fall – I’m teaching one of the sections too, so let me know if you’re interested or have questions!

Graduates with Geographic knowledge of human-environment interaction, especially those with skills GIS, are incredibly desirable in today’s job market. Just saying… 

Lower Temporal Resolution Proxies

Extensive archives of tree-ring data allow for cross dating and the storage of annually resolved data – check out the end of the lecture slides for links to proxy datasets to explore!

Radiometric Dating must be used for proxies without the advantage of annual temporal resolution or for instances of deeper age

Radiocarbon for younger materials (~45-50K)

Potassium-Argon for mid-age to old (~100K or more)

Uranium-Lead for deep time and very old samples(~1 million to a couple billion)

So what are some climate proxies that are not annually resolved, like tree rings, and don’t form or produce a feature each year?

Specifically, what about climate proxies that are built or formed via rates (e.g. sedimentation rates)?

Let’s go!

Lake Sediments

From 500 to about 40,000 years

Lake sediments can tell us about past vegetation through pollen records

Past wildfires from charcoal

Past hurricane activity

and more…

Lake Sediments

Sedimentation rate is extremely important when establishing activity of the past

Ice Cores

1000s to 100,000s of years

VOSTOK project in Antarctica is at 1M now!

All the air bubbles are ancient atmospheres!

Ice Cores

Greenland (general, but not good for CO2 reconstructions due to impurities in the ice) and Antarctica (best for researching past-atmospheres due to purity of ice and minimal contamination from things like dust)

Ocean Sediments

From about 10,000 to 1 million years into the past

Ocean Sediments

Just like lake sediment cores, but from much deeper depths

Sedimentation rates can be MUCH slower, meaning it takes much longer for these sediments to build up. This is good because it means you can investigate processes from deep time.

Speleothems

Pollen gets trapped in the water that drips down to form the cave decorations.

The stalagtites and stalagmites form rings that can be isotopically dated

Varved Sediments

Annual deposition of layers of sediment

Similar to rings on a tree

Depends on complete lack of bioturbation or disturbance

Packrat Middens

Joshua Tree Natl Park, back 7000 years

Pollen analysis as proxy for temperature

Foraminifera (Forams)

Different species survive in different ocean water temps!

Concentrations of species at depth gives a temp proxy

Critical Thinking and Comprehension Check!

Which climate proxy provides the most temporally-resolved data? The proxy with the longest back in time?

You find a piece of carbon from a tree root buried deep in your lake sediment core. You suspect the sediment core in totality to be at most 10,000 years old. Which radiometric dating method do you use? Why?

Explain what this graph is showing. Be sure you include in your answer reference to temperature anomaly vs temperature observation.

Critical Thinking and Comprehension Check!

What are Milankovitch cycles? How do they impact climate? How might they be used to distort a climate change discussion?

As always, if you’d like to review these questions I’ve scattered throughout the lecture slides with me, please don’t hesitate to reach out!

Critical Thinking and Comprehension Check!

Links to Check Out!

Water in the West via Stanford University https://waterinthewest.stanford.edu/

Primer on paleoclimates, a newly updated paleo-temperature multi-proxy database was just published, this is cutting edge stuff!! https://www.nature.com/articles/s41597-020-0531-6

Scott St. George’s commentary on the global asynchrony discovered in the MWP and LIA via the PAGES 2k global temperature reconstruction

https://www.nature.com/articles/d41586-019-02179-2

Looking Ahead…

Week 4 is Discussion #2 and Exam #1 – you will have all week to complete the exam just like labs

We’ll be covering topics related to carbom and the carbon cycle

The only readings for Week 4 are Chp. 5 in your textbook

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