Pre-Course Flashcards
Rate vs Stock (of CO2)
The planet does not care about the annual rate of emission (flow) but the stock of carbon in the atmosphere
“New Normal”
wrongly converys the idea that we’ve simply arrived in some new climate state and that we simply have to adapt
There is no mean, there is no average, there is no return to normal. It’s one-way traffic into the unknown.
What are Greenhouse Gases
- CO2
- Water Vapor
- Nitrous Oxide
- Methane
T or F: Earth climate has been stable for millions of years, untl manking started emitting greenhouse gases and started globl warming?
False
Greenhouse gases make up just 1% of the air. Without these gases, what would our planet be like?
Completely frozen, uninhabitable for humans
Since the industrial revolution (1850), the average climate on Earth has….
increased by 1.2 degrees
Why does the absorption and emission of infrared radiation by the atmosphere warm the planet?
When the greenhouse gases (and clouds, which also act as greenhouse agents) absorb infrared radiation, they must re-emit radiation, otherwise the temperature of the atmosphere would increase indefinitely
Earth’s surface receives almost twice as much radiation from the atmosphere as it does directly from the Sun.
Water Vapor vs Carbon Dioxide
Water takes two weeks to leave the atmosphere, CO2 takes thousands of years
Positive Feedback
if the temperature rises, the amount of water vapor rises with it. But since water vapor is a greenhouse gas, rising water vapor leads to more back-radiation to the surface, which causes yet higher temperatures.
On a 100,000-year time scale, temperature is….
cyclic
Civilization only developed in the past 7,000-8,000 years. What was unique about the climate during this time?
It was unusually stable
The IPCC
The 2015 Paris Agreement
committed 196 countries to limit global warming well below 2C in 2100 and preferable under 1.5C compared to initial average temperature back in 1850
When burning fossil fuels or wood, we release CO2 into the atmosphere. What happens next?
Half the CO2 remains in the atmosphere and the rest goes to the ocean and is processed through photosynthesis
Which are the uncertainties in climate models?
- there is considerable uncertainty in future human emission scenarios
- climate is an inherently complx system, which is impossible to fully predict on all dimensions and interactions (which is why the IPCC always communicated on levels of certainty)
- future temp rises are more difficult to predict because of the risk of cliamte tupping points which may accelerate climate change