- Climate varies naturally due to regular orbital cycles that influence sunlight and atmospheric greenhouse gases, but is also influenced by human activities that are increasing global temperatures - Both natural cycles and human-caused trends affect global climate over time, with temperatures and climates highly variable the farther back in history - Impacts of climate change are widespread and complex, affecting weather patterns, sea levels, ecosystems, agriculture, economies and human health and security

1. Both Melbourne and
Adelaide experienced
weather above 40ºC
(105ºF) this week
Night lows above 30ºC
40+ fires

2. Weather vs climate
Global climate drivers
Climate over geologic time
Cycles and trends
Recent temperature trends
Global warming process
Global warming effects

3. Evidence of Climates Past
• Study geologic (rock and sediment )record
• Recent changes in soil and vegetation
distribution
• Oxygen isotopes (18O/16O) in shell material
Global input changes over geologic time
• Disruption to global circulation patterns
• Atmosphere chemistry
• Volcanoes

4. Distance and angle
from sun is directly
linked to climate & ice
ages, warm spells
Regular orbital cycles have major influence on sun’s warming
Atmospheric influence on keeping the warmth [greenhouse effect]
Trend: temp
increase since
10,000 BP
cycle: 5 peaks
over ~400,000
years
Global temps and climate are a combination of cycles and trends

5. El Niño (Southern
Oscillation) - cyclic warm
event every 4 to 7years
warm waters from the
western South Pacific
extend eastward to South
America
La Niña (a cold event) is
the opposite and cycles
periodically also

6. Part of the recent history of the planet’s climate
Cyclical cold periods
since about 15 Ma
Recent ice age:
Pleistocene Epoch
70,000 – 10,000 BP
Average global temp
~8º below present
Glacial ‘interstadials’ saw
warm spells ~2) above
today’s averages
Massive ice and sealevel swings

7. Massive temp and atmosphere changes
Summary:
• highly variable cycles and trends
• Lots of variation the farther back you go

8. This is by far the biggest, most expensive,
possibly most deadly of all the world’s
environmental issues to date
Affects 1-4 billion people in a direct health
or economic way, that is at our heart
2010 to be the hottest year on record: NASA
Real, marked rise in
recorded temps since 1800
+ 1.0 – 1.3º C
3/8/2013 sciencemag.org

9. Atmospheric process
trapping sun’s heat - stuff in
the atmosphere acts as an
insulating blanket
A natural part of the
system, enhanced with
added power
Greenhouse gases:
chemicals [or particles]
contributing to the warming
effect

10. Hi concentration
Some are common,
some aren’t
Widely variable impacts
Impact - multiply effect x
concentration
Particulates also affect
the system, both plus
and minus
Hi impact

11. Turns out
that the most dramatic
changes are in the
most vulnerable
places on earth
Heat distribution affects weather
Cyclone Phailin slams India's coast

12.  Individual stations
record increase
Adds up to 
MIT projection
scenarios
Current annual

13. Human- 
induced


14. Large, inevitable melting
Large, inevitable rise
-So what?
Population centers
Tidal effects
Erosion effects
Storm effects

16. Water cycle: Overall increase in temperature affects specific aspects of
the water cycle
Droughts: longer, more sever, hotter
Russia: 600+ wildfires, 2011
Floods: extreme and often
Storms: bigger,
maybe stronger or more frequent??
2009 record worst
2011 #4 worst
2013 ??

17. Increased storminess may = increased $$ for preparation or reaction
This is one reason
why flood
insurance may
double in the next
few years

18. We will see many, complex, and surprising
consequences – some have multiplier effects
California Wine: Climate Change Could Decimate
State's Wine Industry

19. example
Multiple pressures
on price of food
goods
Higher
temps
text
Poor
crops
Lower
supply
Extreme
events
Failed
crops
Crop
choice
Hi $

20. Direct
and
Temperature
• Amount
• Distribution
• variability
Rainfall
• Distribution
• Flooding
• Drought
indirect
Biology
• Agriculture
• Invasive
species
• Habitats
• Fire
impacts
… and of course, $

21. Environmental campaigners have argued
that to avoid dangerous climate change
[>2ºC] then up to ¾ of the coal, oil and gas
reserves must be left in the ground
SO maybe, if these stashed resources are
mostly worthless, this will have a major
impact on the share values of the fossil fuel
corporations that own them