Overview
SIMPLE: Heat in minus heat out equals change of heat. Just as a pot of water warms up when more heat is put into the bottom than escapes the top, so the Earth warms when more sunlight is absorbed than outgoing heat emitted. Earth floats in a vacuum so the only heat exchange with the rest of the universe is through radiation. The air is selectively transparent: incoming sunlight passes through but outgoing infrared is absorbed by trace greenhouse gases and then re-emitted. Adding CO2 by burning carbon increases the absorption and re-emission of IR.
SERIOUS: Every bit of coal, oil, and gas we burn increases the amount of IR-absorbing CO2 and thereby warms the Earth. For all practical purposes the warming is permanent. Warming will get worse and worse without bound until we stop making it worse. Global warming is guaranteed to produce extreme heat waves, torrential rainfall, rising seas, increasing water demand, and wildfires. The consequences of unmitigated warming will become totally unacceptable to people, ecosystems, and the global economy. Without strong policy, global warming will quickly become the worst problem in the world.
SOLVABLE: The only way to prevent global catastrophe is to stop setting carbon on fire! More than 90% of the carbon burned is coal, oil, and gas. Two key components of the solution are (1) to live well with less energy and (2) to make energy without combustion. These are big asks especially since 1 billion people are energy poor, but solutions are at hand. Energy efficiency costs negative money, and we can use savings from efficiency to finance clean energy production & distribution. Economists estimate the cost of saving the world to be more than we spend on mobile phones but less than we spend on cars. Technically and economically this is a solved problem. The only impediment is policy.
Learning Objectives
Upon completion of this module you should be able to:
- Explain what determines the temperature of the Earth and how it changes.
- Describe how greenhouse gases absorb and emit radiation.
- Provide examples of real-world consequences of global warming.
- Explain why global warming will continue until we stop burning coal, oil, and gas.
- Describe how to solve the climate problem using energy efficiency and clean energy.
Reading: Simple Serious, Solvable
Slide Deck / Lecture
Review Questions
- Why are scientists so confident that burning carbon will cause climate to change?
- How do tiny amounts of CO2 in the air affect climate? What’s the physical mechanism?
- When was the relationship between CO2 and global warming discovered?
- Under a high-emission scenario, how much warming might we experience in Colorado in your lifetime?
- Explain three impacts of climate change on people and the economy.
- When we stop burning carbon-based fuels, how long will it take for CO2 levels to go down and for climate to return to how it was 100 years ago?
- What will it take to stop climate change from getting worse?
- Explain the tension between solving climate change and economic inequality.
- How can economy-wide electrification be an important component of solving our climate problem?
- What can be done to balance energy supply and demand if we can’t burn carbon anymore?
- Will solving the climate problem be too expensive?
