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
Rank human activies by climate impact
- CO2 from fossil fuel consumption
- methane from ag
- land use change and deforestation
- breathing from humans and animals
What does “Supercharged with carbon, nature breaks our engineered world. Never forget that the economy is a wholly owned subsidiary of nature” mean?
All economic activity is dependent upon that environment and its underlying resource base of forests, water, air, soil, and minerals. When the environment is finally forced to file for bankruptcy because its resource base has been polluted, degraded, dissipated, and irretrievably compromised, the economy goes into bankruptcy with it.
We’re currently on track to ____ CO2 content in the atmosphere by the end of the century
Triple
Could be a 3 degree increase by then
What is the current share of fossil fules in the global energy mix?
In order to contain global warming under 1.5C by 2100, how mcuh should we reduce use of fossil fuels in 2050?
T or F: most climate mitigation measures have focused on the easiest actions, based on a cost-benefit model
True
Problem with Gradualist thinking
Gradualism is rooted in heavily-criticized cost-benefit models. Their logic sounds reasonable if we think that the problem is the rate of carbon emissions and cutting the flow of emissions will reduce global warming. This is not the case. The reason has to do with the stock logic of the greenhouse gas effect.
What was the relationship between global temperature and CO2 levels prior to the Industrial Revolution?
For the past 800,000 years, CO2 levels increased or decreased in response to Earth’s temperature. Today, the opposite is true and CO2 levels drive temperature.
Earth’s CO2 concentration is the same today as it was 3 million years ago, when sea levels were about:
80 feet higher
Climate Risks
- sea level rise (1-2m by 2100)
- heat and humidity
- destructive stroms
- ocean acidification
- food and water
Political and social destabilization is perhaps the greatest and least predictable risk incurred by rapid climate change.
Why does the temperature hardly drop at all over the first thousand after emissions cease?
the temperature hardly drops at all over the first thousand or so years after emissions cease, reflecting mostly the effects of heat storage in the oceans. This is a crucial aspect of the challenge we face: absent technology for removing CO2 from the atmosphere, we will have to live with altered climate for many thousands of years. Thus we have a narrow time window within which to act.
With current technology, guess how much of our energy would need to be non-emitting (renewables, nuclear, etc.) by 2050 to stay within 2ºC of warming?
80%
Which approach has the most straightforward impact on climate change?
mitigation has the most straightforward effect on climate because it attacks the source of the problem. In addition to reducing emissions, some aspects of mitigation might prove to be economically beneficial too.
Due to Earth’s evolving orientation in space relative to the sun, the arctic should be…
cooling
