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Global warming and CO2?Are we headed for global catastrophe in the coming century? Don J. Easterbrook

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Were past global climate changes caused by changes in atmospheric CO2? ... On a recent TV documentary about global warming, a climate modeler said: ... – PowerPoint PPT presentation

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Title: Global warming and CO2?Are we headed for global catastrophe in the coming century? Don J. Easterbrook


1
Global warming and CO2?Are we headed for global
catastrophe in the coming century?Don J.
Easterbrook
2
Is global warming real?
3
Global, N. Hemisphere temperature
4
  • What is the magnitude of present global warming
    compared to global climate changes that have
    occurred in the geologic past?
  • Were past global climate changes caused by
    changes in atmospheric CO2?
  • What is the role of solar changes in global
    climate changes?

5
  • On a recent TV documentary about global warming,
    a climate modeler said
  • CO2 levels in the atmosphere have risen to
    record heights and never before in the history of
    the earth has climate changed as rapidly as in
    the past century, proving that global warming is
    caused by anthropogenic CO2.
  • Our civilization has never experienced any
    environmental shift remotely similar to this.
    Todays climate pattern has existed throughout
    the entire history of human civilization.
    (Gore, 2006)

6
Increase in atmospheric CO2
7
Atmospheric CO2 emissions
8
CO2 cannot have been the cause of climatic
warming episodes prior to 1945 because
atmospheric CO2 didnt increase significantly
until after 1945
? Multiple 25-30 year periods of alternating
warm and cool temperatures have occurred since
the Little Ice Age (1600 AD). Temperatures
during the Little Ice Age were about 4 C (7 F)
lower than present. ? 80 of the CO2 from
human activities was added to the air after 1940,
so these warming episodes had to be natural
fluctuations unrelated to anthropogenic
atmospheric CO2.
9
  • Global temperatures rose 0.5 C (0.9 F) from
    1890 to 1940, well before the sharp rise in
    atmospheric CO2, so it couldnt have been caused
    by CO2. Global temperatures dropped 0.5 C (0.9
    F) from early 1940s to 1977 at a time when atm.
    CO2 was soaring. Since 1890 only about half of
    the global warming corresponds to elevated atm.
    CO2.

10
CO2 began to rise sharply in 1945, but global
temperatures declined for 30 years
11
10 episodes of global warming and cooling that
cannot have been caused by atmospheric CO2
12
10 episodes of global warming and cooling that
cannot have been caused by atmospheric CO2
  • 1. 15,000 yrs ago, sudden climatic warming
    (12 C 21 F) caused dramatic melting of
    large Ice Age ice sheets
  • 2. A few centuries later, temperatures
    plummeted (11 20 F).
  • 3. 14,000 yrs ago, global temperatures
    increased (4.5C 8 F).
  • 4. 13,400 yrs ago, global temperatures plunged
    (8C 14 F)
  • 5. 13,200 yrs ago, global temperatures rose
    rapidly (5C 9 F)
  • 6. 12,700 yrs ago global temperatures plunged
    sharply (8C 14)
  • F) at the start of the Younger Dryas.
  • 7. 11,500 yrs ago, global temperatures rose
    sharply (12 C 21F) marking the end of the
    Younger Dryas.
  • 8. 8,200 yrs ago, a sudden global cooling (4
    C 7 F) lasted a few centuries.
  • 9. 1000 AD, global temperatures rose several
    degrees to begin the Medieval Warm Period,
    which lasted a few centuries, then 1230 AD
    dropped 4C (7 F) in 20 years.
  • 10. 1600 AD, global temperatures cooled several
    degrees at the beginning of the Little Ice Age

13
  • Global climate changes correlate well with
    changes in
  • Solar irradiance.
  • Numbers of sunspots.
  • Production of 10Be and 14C in the atmosphere
    from radiation.

14
Solar effects and climate change
During each global climate change 1. Changes in
the rate of production of 10Be in the upper
atmosphere by radiation indicate changes in
radiation input. 2. Changes in the rate of
production of 14C in the upper atmosphere by
radiation also indicate changes in radiation
input. 3. These changes correlate with changes in
numbers of sunspots and solar irradiance.
15
LITTLE ICE AGE
  • Much colder and wetter, 4 cooler than present
  • 1300 AD, temp. dropped 4 C (7 F ) in 20 yrs
  • Glaciers advanced all over the world
  • Massive crop failures in Europe 1.5 million
    people starved to death Large population decline
    in Europe
  • Wine production dropped sharply
  • Themes River in London froze over
  • Violent storms, early snow, flooding

16
Few sunspots occurred during the Little Ice Age
17
Changes in 14C production rates correlate with
sunspot minimums and climate changes
18
Sunspots and changes in production rates of 10Be
in the upper atmosphere
19
14C production rates match sunspot variations
20
Solar irradiance, sunspots, and glacial advances
(blue)
21
Global temperature change and sunspots
22
Solar irradiance variations correlate with global
temperature change
23
Glaciers on Mt. Baker show a recurring pattern of
advance and retreat that matches the Pacific
Decadal Oscillation and variation in solar
irradiance
24
Easton Glacier, Mt. Baker (modified from Harper,
1993)
1940 to 1956
1956 to 1979
25
Coleman Glacier, Mt. Baker (modified from Harper,
1993)
1940 to 1947
1947-1979
26
Comparison of glacial activity and N.Atlantic
temp changes
27
Warm/cool cycles with constant atmospheric CO2
28
Predicted global temperature changes this century
29
Predicted global temperature changes this century
30
Two checkpoints of the ICPP vs. Easterbrook
projections By 2010, ICPP projects 1 F warmer,
Easterbrook slightly cooler. By 2040 ICPP
projects 2 F warmer, Easterbrook 0.4 F
cooler. After 2040, temp. rises again.
31
CONCLUSIONS
  • During these abrupt climate changes, CO2 was not
    a factor.
  • Far more severe global warming in much shorter
    time has occurred repeatedly in the geologic
    past.
  • Global climate changes have coincided with
    changes in sunspot activity, solar irradiance,
    and production rates of 14C and 10Be
  • 25-30 yr. global warming/cooling phases during
    the past 4 centuries coincide with changes in
    solar irradiance.
  • A 30-yr global cooling period during
    accelerating CO2 levels suggests that CO2 is
    not be the cause of global warming.
  • Projecting the global warming curve for the next
    century suggests cooling from 2006 to 2040,
    warming from 2040 to 2075, and cooling from 2075
    to 2100 with a total warming of only 0.3 degrees
    by 2100.

32
  • Global temperatures rose 0.5 C (0.9 F) from
    1890 to 1940, well before the sharp rise in
    atmospheric CO2, so it couldnt have been caused
    by CO2.
  • 80 of atmospheric CO2 accumulated after the
    sharp rise in CO2 1945, but temperatures for the
    next 30 years cooled 0.5 C (0.9 F) in the
    Northern Hemisphere and 0.2 C (0.4 F)
    instead of global warming.
  • 10 times in the past 15,000 years, sudden
    warming of 8-12 C (14-21 F) occurred in less
    than 100 years and could not have been caused by
    anthropogenic CO2.
  • Glaciers have recorded multiple 25-35 year
    warm/ cool cycles over the past 400 years. Only
    the last one could possibly be attributed to
    atmospheric CO2.
  • During the Little Ice Age, temperatures dropped
    4 C (7 F) in 20 years. The global warming
    that has occurred since then could not be due to
    atmospheric CO2.
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