CC-Lecture2 - CLIMATE
CHANGE
 Lecture
2
 Today:
...

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Unformatted text preview: CLIMATE
CHANGE
 Lecture
2
 Today:
 1.  Climate
change
in
the
past
 2.  How
do
we
affect
climate?
 3.  What
are
the
effects
of
climate
change
 Climate
Change
&
Global
Warming
 *  Climate
change
refers
to
any
significant
change
in
 measures
of
climate
(such
as
temperature,
 precipitation,
or
wind)
lasting
for
an
extended
period
 (decades
or
longer)

 *  Global
warming
is
an
average
increase
in
the
 temperature
of
the
atmosphere
near
the
Earth's
 surface
and
in
the
troposphere

 Climate
 fluctuations
 Geological
scale
 *  The
Earth’s
 climate
has
 changed
many
 times
during
the
 planet’s
history
 How
do
we
know?
 
Evidence
of
past
climate
 change
comes
from:
 *  the
geologic
record
of
 ancient
environments
 and
glaciers

 *  fossils
of
plant
pollen
 *  isotopes
of
elements
 such
as
carbon
and
 oxygen

 *  tree
rings
 *  fossil
distributions

 Present
day
observations
 1,000
Year
Temperature
and
Instrumental
Data
 Northern
Hemisphere
anomaly
(°C)
 Relative
to
1961
to
1990
mean
 1.0
 0.5
 0.0





 ‐ 0.5
 ‐1
.0
 1000



















1200




















1400




















1600




















1800





















2000
 David
D.
Houghton
 Year

 6
 Global
Climate
Change
 How
has
climate
changed
in
the
past?
 ●  Ice
Ages
 ●  Big
swings
in
climate
over
100,000
yrs
 ●  Occurred
over
last
million
years
 ●  Advance
and
retreat
of
ice
sheets
 ●  We
are
in
between
ice
ages
right
now
 21,000
 years
ago
 Today
 Eocene
Warm
Period
 50
million
years
ago
 ●  Palm
trees
in
the
Washington
 State
 ●  Crocodiles
in
the
Arctic
 ●  What
changes
climate?
 Changes
in:
 *  Sun’s
output
 *  Earth’s
orbit
 *  Drifting
continents
 *  Volcanic
eruptions
 *  Greenhouse
gases
concentration
 *  Krakatau
volcano
 (Indonesia)
 eruption
in
1883
 significantly
cooled
 the
global
climate
 and
caused
 spectacular
sunsets
 as
far
as
in
London
 Natural
vs.
antropogenic
 Climate changes can be natural or human caused. Humans can affect the climate by changing the gases in the atmosphere. (greenhouse effect).
 Greenhouse
effect
 Climate
Change:
Basic
Issues
 *  Earth’s
climate
varies
naturally
–
because
of
a
variety
of
cosmological
and
 geological
processes.
 *  “Climate
change”
refers
to
an
additional,
and
relatively
rapid,
change
 induced
by
human
actions.
 *  The
additional
change
–
several
degrees
C
within
a
century
–
will
disrupt
 the
foundations
of
life
on
Earth.

 *  Ecosystems
and
life
in
general
have
evolved
within
a
narrow
band
of
 climatic‐environmental
conditions.
 Climate
Change:
the
“debate”
 Skepticism
is
now
receding.
We
know
that:
  Greenhouse
gas
(GHG)
concentrations
are
increasing
  GHGs
are
very
important
agents
controlling
temperature
  World
average
temperature
has
risen
relatively
fast
over
the
 past
30
years
  Sea‐level
rise
is
gradually
accelerating
  Many
temperature‐sensitive
systems/processes
have
changed
 over
the
past
decades
 If
climate
has
always
changed,
then
why
is
 global
warming
so
controversial
today?

 *  greatly
accelerated
the
warming
process

 *  Pandora’s
box:
unexpected,
uncontrollable
changes
 to
life
on
our
planet

 *  The
rate
of
change
increasing
rapidly:
life
on
Earth,
 including
humans,
will
not
have
time
to
adapt
to
the
 changing
conditions

 Have
we
changed
the
climate?
   Our
use
of
fossil
fuels
(oil,
natural
gas,
coal)
releases
carbon
 dioxide
into
the
atmosphere
   The
amount
of
carbon
dioxide
and
other
gases
released
into
the
 atmosphere
is
growing
 *  Factories,
motor
vehicles,
household
activities,
and
agricultural
 activities
contribute
to
climate
change.
 • Global
surface
temperature
has
 increased
by
0.74
degree
C
 • Global
sea
level
has
risen
by
17
 cm
during
the
20th
century
 • More
regional
changes
have
also
 been
observed
 • Arctic
temperatures
and
 ice
,Ocean
salinity,
Wind
 patterns,
Droughts,
 Precipitations,
frequency
of
 heat
waves
 Changes
in
 global
 temperature
 over
the
last
 125
years
‐ After
 Industrial
 Revolution
 Intergovernmental
 Panel
on
Climate
 Change
 • The
IPCC
is
a
scientific
 intergovernmental
body
set
 up
by
the
World
 Meteorological
Organization
 (WMO)
and
by
the
United
 Nations
Environment
 Program
(UNEP)
 • was
established
to
provide
 the
decision‐makers
and
 others
interested
in
climate
 change
with
an
objective
 source
of
information
about
 climate
change

 Let’s
watch
a
video:
 Scientific
debate
on
climate
change
 http://youtu.be/52KLGqDSAjo
 What
are
the
effects
of
Global
Climate
 Change?
 Effects
of
Global
Change

 *  Sea‐level
rise
 *  Has
risen
10‐20
cm
(4‐8
inches)
during
the
20th
century
 *  Resulting
from
the
melting
of
glaciers
&
the
expansion
 of
water
with
heat
 *  Low‐lying
coastal
communities
 *  Wetlands
&
coral
reefs
 *  Models
predict
that
sea
level
may
rise
as
much
as
85
 cm
(33
inches)
during
the
21st
century

 Amsterdam
 Swinoujscie
 Brest
 1
meter 2
meters 4
meters 8
meters Mountain
glaciers:

 Mount
Kenya
in
Africa

 1952 2008 2005 1963 Glaciers
are
retreating
all
over
the
world 
 The
South
Cascade
glacier
(Washington
State)
retreated
 dramatically
in
the
20th
century
 1928 2000 •  Mountain
glaciers
 •  Chacaltaya
glacier,
Andes
 Mountains
 •  Might
disappear
in
7‐8
years
 (water
supply
for
La
Paz,
 Bolivia)
 Effects
of
Global
Change
 *  Melting
Arctic
Sea
Ice
 *  summer
sea
ice
in
the
 Arctic
is
about
half
as
 thick
as
it
was
in
1950

 *  melting
Arctic
sea
ice
 may
eventually
lead
to
 global
changes
in
water
 circulation

 1979
 2003
 NASA
photographs
show
the
minimum
Arctic
sea
ice
 concentration
in
1979
at
left
and
in
2003.Satellite
 passive
microwave
data
since
1970s
indicate
a
3%
 decrease
per
decade
in
arctic
sea
ice
extent.

 Since
1979,
the
size
of
the
summer
polar
ice
cap
has
shrunk
more
than
20
 percent.

 (Illustration
from
NASA)

(http://www.nrdc.org/globalWarming/qthinice.asp)
 Effects
of
Global
Change
 *  Warmer
Oceans
 *  a
quarter
of
the
world’s
coral
 reefs
have
died
in
the
last
few
 decades,
many
of
them
affected
 by
coral
bleaching
 *  Future
warming
may
have
 consequences
for
other
 communities
of
marine
life
as
 well
 *  Warmer
tropical
ocean‐stronger
 hurricanes



 Effects
of
Global
Change
 *  Floods
 *  Warmer
temperatures
cause
more
evaporation
of
 water‐more
precipitation
 *  5‐10%
increase
in
precipitation
over
the
past
century

 Effects
of
Global
Change
 *  Droughts
 *  While
some
parts
of
the
world
are
treated
to
more
 precipitation
as
global
warming
persists,
other
 parts
may
experience
increased
levels
of
drought
as
 temperatures
rise

 Effects
of
Global
Change
 *  Heat
Waves
 *  a
great
health
risk

 *  a
1995
heat
wave
in
 Chicago
caused
514
heat‐ related
deaths

 *  likely
to
be
an
increase
in
 the
number
of
heat
 waves
and
their
intensity

 • 2003, European
hottest
 summer
in
over
500
years
 • Average
3.5
degree
C
 above
normal
 • 22,000
to
45,000
heat‐ related
deaths
over
two
 weeks
 Effects
of
Global
Change
 *  Ecosystems
Change
 *  Either
ecosystems
will
move,
 migrating
to
new
locations
that
 are
more
like
their
current
 climate

 *  or
they
will
change,
adapting
to
 the
changed
climate,
with
some
 species
becoming
less
abundant
 or
locally
extinct
and
others
 thriving
under
the
new
 conditions

 Effects
of
Global
Change
 *  Agriculture
 *  many
areas
are
becoming
unsuitable
for
agriculture

 *  Less
agriculture
means
less
food

 *  Scientists
predict
that
by
the
2080s,
about
80
million
 people,
mostly
within
Africa,
will
be
hungry
because
of
 climate
change

 ...
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