1.
2003 european heat wave: - mortality increase in susceptible populations
- An extra ca. 22,000 to 45,000 people died in a two-week period
2.
attributing extreme events: scientist cannot link extreme weather to climate change
- extreme events are expected in stable climates
- however, the probability of extreme warm events is likely to increase
3.
attribution: - 36 gigatons of carbon released in 2008.
- from fossil fuel emissions (29 Gt) and other human activites (7 Gt).
4.
changes in extreme weather?: - increase in: # of frost-free days
- warm extremes (ex:summer 2003)
- increased strength (not frequeny) of hurricanes
- heavy precipitation events
5.
changes in extreme weather?: - increased strength of hurricanes
- oceanic heat is the fuel for hurricanes
- also related to wind changes
6.
Climatic Research Unit/Hadley center (CRUTEM3): has 4349 stations
7.
Consequences: - reduced glacier extent
- glaciers buffer water supplies by allowing gradual melt
- less glacier cover= more vulnerable water supplies
- andes, alps, himalayas
- increased wild fires
- combustion is favored in warmer conditions
- more warm climate extremes
8.
consequences on energy demand/costs?: - decreased winter/night heating
- increased air conditioning
9.
effects on the hydrologic cycle: - start with warm oceans gets processed by wind and then goes down by rain, etc.
10.
Geographic trends in temp, 1979-2005: - warming is not the same everywhere.
- higer over land than the ocean.
- higher in the Arctic
- That warming is happening nearly everywhere is consistent with a GHG forcing, but not with some sort of natural climate variability.
11.
Have emissions been enough to cause the increase?: Yes
12.
How are global surface temperature measured?: - 1850 to present: thermometers at of thousands stations.
- coverage gets better towards the modern.
- after 1957 much better when measurements began on Antartica.
- Best after 1980 when satellites began operation.
13.
NASA's Goddard Institute of Space Sciences (GISS): has 7200 stations
14.
National Climatic Data Center (US), (NCDC): has 7230 stations
15.
Palmer Drought Secerity Index (PDSI): - how much moisture is held in the soil.
16.
snowpack and fires: warming-->early snowpack melting-->earlier date of soil drying-->longer and stronger fire season
- antecedent conditions: winter snow amount is related to summer fire season
17.
soil-moisture warming feedback: positive feedback
- warming-->more soil water evaporation-->more heat absorbed by soil surfaces--> more warming
- Drought leads to warming and warming leads to drought
18.
Souther Hemisphere: - still has gaps in the souther hemispher because it has a lot of land.
- less data during world wars
- combined all records they find and thats how they get the information.
19.
the 1930s dust bowl: - related to la nina oscillation and poor agriculture crops
- confluence of climatic drought and human influence
- dramatic socioeconomic impact
- partly driven by changes in ocean circulation
20.
tree-ring evidence for megadroughts: - partly driven by pacific ocean's el nino/southern oscillation
- la nina (cool pacific ocean) conditions favor drought in the western US
21.
why are warmer nights becoming the norm?: - an expected observation because night is long-wave radiation is most active
- Then trapped by GHGs
22.
Why did it cool 1950-1970?: - period of rapid post-WWI industrialization.
- Emission of soot (GHGs) into atmosphere.
- Soot blocked out solar insolation.
- Grand Irony: cleaning up our smokestacks removed the soot cooling effect.
