4-Nature-of-CC.pdf powerpoint presentation

this is about the nature of climate change its causes and impacts

1. GLOBAL CLIMATE
CHANGE
Causes, Impacts
and Dealing with it

2. Global Climate Change
•Identifiable change in the climate of
Earth as a whole that lasts for an
extended period of time (decades or
longer)
–When due to natural processes, it is
usually referred to as global climate
variability
–Usually refers to changes forced by
human activities that change the
atmosphere

3. Climate Change
•Evidence for Climate Change
11 of the 12 years between 1995 and 2006 were among
the twelve warmest years since the mid-1800s
Phenological spring in N. hemisphere now comes 6 days
earlier
•Warming is not due to natural causes
Human produced greenhouse gases are most plausible
explanation

4. CAUSES OF CLIMATE CHANGE
•Changes in the atmosphere
•Natural processes
Volcanoes
Tectonic plate movement
Changes in the sun
Shifts in Earth’s orbit
•Human activities – any activity that releases greenhouse
gases” into the atmosphere

5. CAUSES

7. •Temperatures are rising
•Sea levels are rising
•The ocean is acidifying
•Climate change is reflected in
water cycle changes and in
extreme weather

Temperature rise, indicated by color (red=higher rate of
increase). Earth’s surface temperature has risen ~1.3˚ F since
1850.
Image courtesy of the Joint Institute for the Study of the Atmosphere & Ocean, U. of
Washington.

8. Temperatures are rising


Average global surface temperature has risen ~1.3°F since
1850

If emission rates for greenhouse gases continue on their
current track, models indicate that the globe will be 4.3 to
11.5°F warmer by 2100 than it was in 1990.

9. Mean Annual Global Temperature 1960-2005

10. Sea levels are rising

Warmer temperatures cause glaciers and land ice to melt (adding
more volume to oceans),sea water to expand in volume as it warms

Models indicate that sea levels could rise 2 feet or more by 2100
compared to 1990 levels.

 Sea level rise caused in 2 ways
Thermal Expansion: Water expands as it warms
Melting of land ice: Retreat of glacier and thinning of ice at the poles

11. water expands
when heated,
water level
rises as a result
Expansion of water by heating
Rise in global sea temperature leads to expansion of sea water and a rise in sea level

12. ( Source : US Geological Survey)
Global warming leads to the melting of ice caps over polar land areas and the glaciers on high mountains.
The melted ice-water flows into the sea and contributes to the sea level rise.
Melting of ice caps and glaciers

13. Melting Ice and Rising Sea Levels
1957
1998

14. Sea level rise
global mean sea level
measured by tide gauge
and satellite

global mean sea level
height rose at a rate of
1.7 mm per year during
the period 1901-2010.

rising rate is higher at 3.2
mm per year during the
period 1993-2010.

15. The ocean is acidifying

Much of the carbon dioxide emitted by human activity has already
been taken up by the ocean, thus moderating the increase of carbon
dioxide in the atmosphere.

However, as carbon dioxide dissolves in seawater, it forms carbonic
acid, acidifying the ocean.

Ocean acidification will likely cause serious harm to marine organisms
such as corals, lobsters, and sea urchins.

16. Ocean as CO
2 sink - excess CO
2 is starting to harm ocean life

17. Water cycle changes

Warmer temperatures also mean higher evaporation rates and
thirstier plants and people, increasing demands for water.

Projections indicate that on average dry areas will tend to get drier,
and wet areas will tend to get wetter.

.
•Some areas will get
more water, some
areas will have
greater droughts
–Ex: Hurricanes will
likely get stronger

18. ECOLOGICAL IMPACTS
Living things are intimately connected to their physical
surroundings.
Ecosystems are affected by changes in: temperature,
rainfall/moisture and pH

19. As a result of climate change, species and ecosystems are
experiencing changes in:
ranges
timing of biological activity
growth rates
relative abundance of species

cycling of water and
nutrients
the risk of disturbance
from fire, insects, and
invasive species

20. Range Shifts
Species are relocating to areas with more
tolerable climate conditions.
Range shifts particularly threaten species
that:
–cannot move fast enough
–depend on conditions that are
becoming more rare (like sea ice)

21. Timing of Biological Activity
Some seasonal biological activities are
happening 15-20 days earlier than several
decades ago:
–Trees blooming earlier
–Migrating birds arriving earlier
–Butterflies emerging earlier
Changes in timing differ from species to
species, so ecological interactions are
disrupted.

22. If all of the species in an ecosystem shifted their seasonal
behavior in exactly the same way, shifts in the timing of
biological activity might not create problems.

But when a species depends upon another for survival and
only one changes its timing, these shifts can disrupt
important ecological interactions, such as that between
predators and their prey.
Timing of Biological Activity

23. •Zooplankton in parts of California Current have decreased
by 80% since 1951
–Effecting entire food chain
•Decline in krill around Antarctica
–Caused decrease in penguin populations
•Species have shifted their geographic range
•Migrating birds are returning to summer homes earlier
–Food is not available at this time
Effects On Organisms

24. Effects on Organisms - Coral Reefs
Coral reefs can be bleached (right) due to increase in water
temperature
–Affects coral symbiotes and makes them more susceptible to
diseases to which they would otherwise be immune

25. Effect on Organisms - Vegetation
Beech Tree Range

26. Effects on Human Health
Increased number of heat-related illnesses and deaths

27. Effects on Agriculture
•Difficult to anticipate
–Productivity will increase in some areas and decrease in others
•Rise in sea level will inundate flood plains and river valleys (lush
farmland)
•Effect on pests is unknown
•Warmer temperatures will decrease soil moisture- requiring more
irrigation
•Location (i.e. elevation and altitude) where certain crops can be grown
may have to change

28. WHAT CAN BE
DONE?

29. a. Increase absorption of greenhouse gases from the
atmosphere and store them in solid form
Tree planting
To absorb all CO
2
released by
industries would
require 25 M km
2
of
forests (19% of the
Earth’s land surface)

30. Expansion of Coral Reef

31. b. Reduce the input of greenhouse gases into the atmosphere
1.Montreal Protocol on Substances that Deplete Ozone Layer
agreement stipulating the phase-out of ozone depleting substances
by certain schedules

2. Kyoto Protocol
 international agreement to limit the world GHG emission
 US and Australia did not ratify the agreement

32. How to deal with Global Climate Change
Two ways to attempt to manage climate change
Mitigation
•Focuses on limiting greenhouse gas emissions to moderate
global climate change
 Adaptation
•Focuses on learning to live with to the environmental
changes and societal consequences brought about by global
climate change

33. Dealing with Global Climate Change- Relationship Between
Mitigation and Adaptation

34. Dealing with Global Climate Change
Mitigation
•Locate/invent alternative fuels to fossil fuels
•Increase efficiency of cars and trucks
•Sequestering carbon before it is emitted
•Plant and Maintain trees to naturally sequester
carbon

35. Dealing with Global Climate Change
Adaptation
•Rising sea levels and coastal populations
Move inland
Construct dikes and levees
•Adapt to shifting agricultural zones

36. “There were rumors of
unfathomable things, and
because we could not
fathom them we failed to
believe them, until we
had no choice it was too
late.”





THINK GLOBALLY,
ACT LOCALLY!