4 essay question from lectures
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week4.pptxCarbon 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
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!
