Flashcards in BIO220 Lecture 22 Deck (61)
Earth entered __th major ice age 2.58 million years ago
Ice age has alternating ___ and ___ periods
glacial & interglacial
- sinusoidal temperature changes
We are exiting the interglacial period in the next...
10-50 thousand years
long-term prediction of climate? short-term?
long-term: entering glacial period
4 pioneers of climate prediction
How different gasses absorb radiation
- greenhouse effect of water vapour (how water holds heat)
- diff gasses store diff amounts of heat
Overall effect of CO2 as a greenhouse gas
- double CO2 = 4*C increase in global temperature
- alternating glacial & interglacial periods due to fluctuations in CO2 concentration
- coal burning will fend off next ice age
interglacial & glacial cycles based on wobbling of earth's axis and our position in the universe
Why do we have alternating glacial & interglacial periods?
- Arrhenius: CO2 concentration
- Milankovich: wobbling of earth's axis
^ both contribute
Primitive equations for modelling weather
Calculate first numerical weather prediction
ENIAC's breakthrough prediction in 1950
predicted 24h of weather in 24h
What can we predict far in advance: weather or climate?
why can't we predict weather far in advance?
- chaotic nature
- estimation & computation limitations
statistics of weather
How to predict future climate?
Look at mean weather for current month + standard deviations -> project forward.
e.g. April 2014 is 10*C +- 5*C, so April 2020 will probably be about the same
intergovernmental panel on climate change
Backward prediction (climate)
Use method of predicting future climate for data in 1990, and see if predicted result match real result of 2000
- allow us to see if our method of prediction is good
Different groups are studying climate around the world. What do they do?
- model building
- collect data on past climates
- validation & approve causes
IPCC was established by __ in __
What does the IPCC do?
Review all available research and get a central central opinion -> core findings on climate that everyone can agree
- does not do its own research
Why was IPCC established?
avoid "alarmist" projections by independent scientists
Cools earth; reflection of solar radiation back into space
Heats earth; traps infrared radiation emitted by the Earth
__ of the solar radiation is absorbed by the Earth's surface
___ radiation is emitted from Earth's surface
Past climate cooling is associated with... (Albedo effect)
uplift of mountain ranges -> snowy regions
What reflects the most light? What problem does this cause?
Snow > crops > forest > water;
When snow (75%) melts to water (5%) due to heat, Earth with heat even MORE
Keeling's annual measurement of CO2 in Hawaii showed...
- drop due to northern summer (photosynthesis)
- rises due to northern winter