What do you see?

The image, by Katsushika Hokusai 葛飾 北斎, is Ejiri in Suruga Province (Sunshu Ejiri), from the series "Thirty-six Views of Mount Fuji (Fugaku sanjurokkei)", 1825-1838. The Art Institute of Chicago. [Creative Commons 0 license]

Jeff Wall, A sudden gust of wind, after Hokusai, 1993.

Climate change

...is the organizing theme of this Natural World Perspectives science class.

Consider the words climate and weather. What are some definitions that distinguish these words from each other?

Make up a simile that distinguishes climate and weather. E.g. "If weather is like _____ then climate is like _____."

What factors do you know about or suspect that affect Earth's climate (which is different from its *weather*)?

In 1896 Svante Arrhenius calculated that:

• cutting the concentration of carbon dioxide, $CO_2$, in Earth's atmosphere in half would be sufficient to bring on another ice age.
• doubling the concentration would increase Earth's average surface temperature by 5-6 C (9-11 F).

What do you know or suspect might be affecting the amount of $CO_2$ in Earth's atmosphere?

Here's the main chemical reaction that happens when coal (which is mostly just carbon, $C$) is burned in the atmosphere (which contains oxygen gas, $O_2$) $$C+O_2 \to CO_2 + \text{heat}.$$ Arrhenius was aware of how much coal was being burned during his time (~120 years ago), and thought a doubling might eventually occur ... perhaps in a few thousand years.

What percentage of the atmosphere do you think is carbon-dioxide?

Here is a diagram showing the composition of Earth's atmosphere (Wikipedia).

Measurements of $CO_2$ in Earth's atmosphere since the late 1950's, as observed in Hawaii:

By about what percentage has $CO_2$ increased in the time of this graph? (How does that compare with Arrhenius' "doubling"?)

Why would you guess that an arid (dead) volcano on one of the Hawaiian islands in the middle of the Pacific might be a good place to make measurements of $CO_2$? (Hint: How might people challenge you if the graph you showed them was based instead on measurements made in downtown New York City?)

Internal research carried out by oil company Exxon in the 1970's confirmed the role of burning fossil fuels in increasing $CO_2$, and the seriousness of the situation.

Why would you guess people choose to "believe" or not in global warming (or, that it's a result of human actions)?

Major themes

...in our class:

• *Experiencing* science: making measurements & arguing over their meaning and value; making mathematical models and evaluating against observation.
• Science related to climate change (natural and human): Astronomy, geology, chemistry (combustion), heat, gravity, electro magnetic waves.
• The two "laws" of thermodynamics - Energy conservation, and entropy--the tendency for energy to end up in the form of heat.
• Addressing climate change--how we get the energy we use and what we could change.
• Human interactions with our environment--a historical perspective.
• Feedback cycles in complex systems (environmental and social).
• Reading & interpreting graphs; Putting numbers in context.

We are still a part of the natural world which our ancestors lived in, and which sustained them.

Some astronomy

Along with the physics of energy/entropy, we'll study some astronomy:

• The fairly successful Greek attempt to "explain" observations of the night sky, that survived for the better part of 2000 years,
• What changed to overturn the 2000-year-old consensus, (and the elusivity of 'truth'),
• To get some context for what "natural" variations of Earth's climate have been in the past, and compare to current theories about climate change.

Tikal

Tikal was a Mayan city in present-day Guatemala

The Temple of the Great Jaguar, Tikal, built ca. 732 AD

Writing

Images from stele (plural of "stela") in the court of the Jaguar Temple

Calendar: The Long Count calendar recorded dates relative to the Mayan creation date (in our 3114 BC).

The Mayan calendar was much more precise than contemperary calendar systems in Europe.

Astronomy / calendar

"Zenith tube" @ Xochicalco, MX, for observing the sun passing directly overhead.

Tikal was abandoned sometime between 800-1000 AD.

??? Could that happen to our civilization too? What can we learn from the collapse of the Maya? Or were they too different?

Image credits

Jack Eidt, Ken Douglas, Jocelyn Emberton Underwood, C. Ruggles. More about Mayan astronomy, PublicDelivery.org.