HPU NCS2200 earth science for elementary education majors summer 2014 online class global climate change lecture part 2

1. 21.7 Greenhouse Effect: the carbon
cycle and global warming
• Consequences of global warming
– Increased temperatures tend to decrease
plant productivity
– Parasites and other plant ailment become
more prevalent during higher temperatures
• Precipitation and soil moisture effects
– In a warmer world, precipitation and
evaporation should increase

2. 21.7 Greenhouse Effect: the carbon
cycle and global warming
• Extreme weather events – models indicate
more and worse
– Data shows this prediction proving out
• Changes in biodiversity – in some latitudes,
70% of habitats will be affected
– Sensitive or specialist species could die off
– E.g.: polar bears are endangered due to lack of
pack ice

3. 21.7 Greenhouse Effect: the carbon
cycle and global warming
• Sea-level changes – sea-level has risen
markedly from 1900 to 2000
– water expands when warm
– Glacial melting is increasing
• Effects on people
– Tropical diseases flaring up in new areas
– Population stress on food and water supplies as
well as other global systems

4. Fig. 21.17, p.546

5. 21.8 Feedback and threshold
mechanisms in climate change
• Many Earth systems exhibit non-linear
responses to change
– Albedo effects – melting ice decreases albedo
through loss of “white” and changes in
vegetation. What snows are left are blocked by
brushy growth
– Imbalances in rates of plant respiration and
photosynthesis. Decay respiration increases
when warmer, releasing more CO2 which makes
it warmer.

6. Fig. 21.18, p.548

7. 21.8 Feedback and threshold
mechanisms in climate change
 West Antarctic ice shelf has collapsed in sections.
Grounded ice is thinning and lifting in others, and
floating ice is breaking up.
• As ice floats, seawater creeps beneath causing glacial
movement to increase.
• Break-up of the West Antarctic Ice Sheet will raise sea
level

8. Fig. 21.19, p.549

9. 21.8 Feedback and threshold
mechanisms in climate change
• Thermohaline circulation – how global
warming could cause global cooling
– Warmer sea surface temperature could slow
or stop vertical currents
– This would stop, or re-route the Gulf Stream,
which would cool the Earth
– Thermohaline currents have decreased 30%
from 1988 - 2000

10. Fig. 21.20, p.550

11. Fig. 21.16, p.544

12. Consequences of
Global Climate Change
• These two websites contain videos discussing the
consequences of climate change. The National
Geographic is a short 8 minute video. The
rockhopper is a series of 1 hour videos produced by
BBC.
– http://www.rockhopper.tv/search?form=sea
rch&q_widget=hot+cities&submit=Search
– http://video.nationalgeographic.com/video/
player/environment/global-warming-
environment/way-forward-climate.html

13. 21.9 The Kyoto treaty on greenhouse
warming
• Dec. 1997, 160 nations met to discuss
global warming
– By Feb. 2005 a treaty was ratified by many of
them
– Creates a global trading market for CO2
emissions
– Sets limits and goals to enact
– Caps and goals tied to nations’ economies

14. 21.9 The Kyoto treaty on greenhouse
warming
– The U.S. has never ratified the treaty
– Treaty supporters argue:
• Wealth not necessarily tied to fuel consumption
• Curbing consumption and emissions could help the
economy
• Models show the longer we wait, the worse it will get
• Consider the alternatives: runaway temperature
changes, famine, global unrest.
• The treaty expires in 2012 – the sequel is looking
less than inspired.

15. Fig. 21.21, p.551

16. What’s next
???
• The Durban Conference held in 2011 attempts
to develop the follow on protocol to the Kyoto
treaty.
• Discussions continue from that forum to
establish the next steps in addressing climate
change.
• http://unfccc.int/meetings/durban_nov_2011
/meeting/6245.php