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GLOBAL WARMING

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GLOBAL WARMING An Inconvenient Truth or A Convenient Lie What should I know for the test? What is it? Read PDF p.30 What causes it? What does Al Gore say? – PowerPoint PPT presentation

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Title: GLOBAL WARMING


1
GLOBAL WARMING
  • An Inconvenient Truth
  • or
  • A Convenient Lie

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What should I know for the test?
  • What is it? Read PDF p.30
  • What causes it?
  • What does Al Gore say? (worksheet)
  • What do opponents of Global Warming say?
  • What were the major findings of the IPCC?
  • What are some future climate projections?
  • What does the Kyoto Protocal do?
  • Why does the US refuse to ratify it?
  • What can you do?

17
Intergovernmental Panel on Climate
Change FindingsThe Upcoming Slides are taken
from IPCC Report, 2-2007
  • About IPCC

18
Direct Observations of Recent Climate Change
  • Warming of the climate system is undeniable,
    as is now evident from observations of increases
    in global average air and ocean temperatures,
    widespread melting of snow and ice, and rising
    global mean sea level.

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Direct Observations of Recent Climate Change
Global mean temperature Global average sea
level Northern hemisphere Snow cover
20
Direct Observations of Recent Climate Change
  • At continental, regional, and ocean basin
    scales, numerous long-term changes in climate
    have been observed. These include
  • changes in Arctic temperatures and ice
  • widespread changes in precipitation amounts,
    ocean salinity and wind patterns
  • extreme weather including droughts, heavy
    precipitation, heat waves and the intensity of
    tropical cyclones have increased in intensity

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Global mean temperatures are rising faster with
time
Period Rate Years ?/decade
22
Arctic vs Global annual temperature anomalies
(C)
Warming in the Arctic is double that for the
globe from 19th to 21st century and from late
1960s to present. Warmth 1925 to 1950 in Arctic
was not as widespread as recent global warmth.
Note different scales
23
Further Changes in Artic and Frozen Ground
  • Annual average Arctic sea ice extent shrunk by
    2.7 per decade, decreases in summer 7.4
  • Temperatures at the top of permafrost layer have
    generally increased since the 1980s by up to 3C
  • The maximum area covered by seasonally frozen
    ground has decreased by about 7 in Northern
    Hemisphere since 1900, in spring of up to 15.

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Changes in Precipitation, Increased Drought
  • Significant increase in precipitation in eastern
    parts of North and South America, northern Europe
    and northern and central Asia.
  • The frequency of heavy precipitation events has
    increased over most land areas - consistent with
    warming and increases of atmospheric water vapor
  • Drying in the Sahel, the Mediterranean, southern
    Africa and parts of southern Asia.
  • More intense and longer droughts observed since
    the 1970s, particularly in the tropics and
    subtropics.

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Other changes in Extreme Events
  • Widespread changes in extreme temperatures
    observed
  • Cold days, cold nights and frost less frequent
  • Hot days, hot nights, and heat waves more
    frequent
  • Observational evidence for an increase of intense
    tropical cyclone activity in the North Atlantic
    since about 1970, correlated with increases of
    tropical sea surface temperatures

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Proportion of heavy rainfalls increasing in most
land areas
Regions of disproportionate changes in heavy
(95th) and very heavy (99th) precipitation
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Drought is increasing most places
Mainly decrease in rain over land in tropics and
subtropics, but enhanced by increased atmospheric
demand with warming
The most important spatial pattern (top) of the
monthly Palmer Drought Severity Index (PDSI) for
1900 to 2002. The time series (below) accounts
for most of the trend in PDSI.
28
Circulation change
  • Climate change is affecting storm tracks, winds
    and temperature patterns

29
North Atlantic hurricanes have increased with SSTs
N. Atlantic hurricane record best after 1944 with
aircraft surveillance. Global number and
percentage of intense hurricanes is increasing
(1944-2005)
SST
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Snow cover and Arctic sea ice are decreasing
Spring snow cover shows 5 stepwise drop during
1980s
Arctic sea ice area decreased by 2.7 per
decade (Summer -7.4/decade)
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Glaciers and frozen ground are receding
Area of seasonally frozen ground in NH has
decreased by 7 from 1901 to 2002
Increased Glacier retreat since the early 1990s
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Direct Observations of Recent Climate Change
  • Some aspects of climate have not been observed
    to change
  • Tornadoes
  • Dust-storms
  • Hail
  • Lightning
  • Antarctic sea ice

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Human and Natural Drivers of Climate Change
  • CO2, CH4 and N2O Concentrations
  • - far exceed pre-industrial values
  • - increased markedly since 1750
  • due to human activities

Relatively little variation before the industrial
era
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Understanding and Attributing Climate Change
  • Continental warming
  • likely shows a significant contribution over
    the past 50 years

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Understanding and Attributing Climate Change
  • Most of the observed increase in globally
    averaged temperatures since the mid-20th century
    is very likely due to the observed increase in
    greenhouse gas concentrations. This observed
    warming over the last 50 years is likely to have
    been due to the increase in greenhouse gas
    concentrations. H
  • Human influences now extend to other aspects of
    climate, including ocean warming,
    continental-average temperatures, temperature
    extremes and wind patterns

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Projections of Future Changes in Climate
  • Continued greenhouse gas emissions at or above
    current rates would cause further warming and
    induce many changes in the global climate system
    during the 21st century that would very likely be
    larger than those observed during the 20th
    century.

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Projections of Future Changes in Climate
  • For the next two decades a warming of about 0.2C
    per decade is projected for a range of SRES
    emission scenarios.
  • Even if the concentrations of all greenhouse
    gases and aerosols had been kept constant at year
    2000 levels, a further warming of about 0.1C per
    decade would be expected.
  • Earlier IPCC projections of 0.15 to 0.3 oC per
    decade can now be compared with observed values
    of 0.2 oC

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Projections of Future Changes in Climate
Best estimate for low scenario (B1) is 1.8C
(likely range is 1.1C to 2.9C), and for high
scenario (A1FI) is 4.0C (likely range is 2.4C
to 6.4C). Broadly consistent with span quoted
for SRES in TAR, but not directly comparable
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Projections of Future Changes in Climate
Projected warming in 21st century expected to
be greatest over land and at most high
northern latitudes and least over the Southern
Ocean and parts of the North Atlantic Ocean
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Projections of Future Changes in Climate
Precipitation increases very likely in high
latitudes Decreases likely in most subtropical
land regions
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PROJECTIONS OF FUTURE CHANGES IN CLIMATE
  • Snow cover is projected to go down
  • Widespread increases in thaw depth hurt most
    permafrost regions
  • Sea ice is projected to shrink in both the Arctic
    and Antarctic
  • In some projections, Arctic late-summer sea ice
    disappears almost entirely by the latter part of
    the 21st century

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PROJECTIONS OF FUTURE CHANGES IN CLIMATE
  • Very likely that hot extremes, heat waves, and
    heavy precipitation events will continue to
    become more frequent
  • Likely that future tropical cyclones will become
    more intense, with larger peak wind speeds and
    more heavy precipitation

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PROJECTIONS OF FUTURE CHANGES IN CLIMATE
  • Global warming and sea level rise would continue
    for centuries due to the timescales associated
    with climate processes and feedbacks, even if
    greenhouse gas concentrations were to be
    stabilized.

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What Global Warming?
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  • What follows is a very brief summary
  • of the science that the former Vice
  • President promotes in either a wrong
  • or misleading way(according to Senator James
    Inhoffe)
  • He promoted the now debunked hockey stick
    temperature chart in an attempt to prove mans
    overwhelming impact on the climate
  • He attempted to minimize the significance of
    Medieval Warm period and the Little Ice Age
  • He insisted on a link between increased hurricane
    activity and global warming that most sciences
    believe does not exist.

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  • He asserted that todays Arctic is experiencing
    unprecedented warmth while ignoring that
    temperatures in the 1930s were as warm or warmer
  • He claimed the Antarctic was warming and losing
    ice but failed to note, that is only true of a
    small region and the vast bulk has been cooling
    and gaining ice.
  • He hyped unfounded fears that Greenlands ice is
    in danger of disappearing
  • He erroneously claimed that ice cap on Mt.
    Kilimanjaro is disappearing due to global
    warming, even while the region cools and
    researchers blame the ice loss on local land-use
    practices
  • He made assertions of massive future sea level
    rise that is way out side of any supposed
    scientific consensus and is not supported in
    even the most alarmist literature.

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  • He incorrectly implied that a Peruvian glacier's
    retreat is due to global warming, while ignoring
    the fact that the region has been cooling since
    the 1930s and other glaciers in South America are
    advancing
  • He blamed global warming for water loss in
    Africa's Lake Chad, despite NASA scientists
    concluding that local population and grazing
    factors are the more likely culprits
  • He inaccurately claimed polar bears are drowning
    in significant numbers due to melting ice when in
    fact they are thriving
  • He completely failed to inform viewers that the
    48 scientists who accused President Bush of
    distorting science were part of a political
    advocacy group set up to support Democrat
    Presidential candidate John Kerry in 2004

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Kyoto Protocol
  • The Kyoto Protocol is an agreement made under the
    United Nations Framework Convention on Climate
    Change (UNFCCC).
  • Passed in 1997
  • Countries that ratify this protocol commit to
    reduce their emissions of carbon dioxide and five
    other greenhouse gases, or engage in emissions
    trading if they maintain or increase emissions of
    these gases.

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US Refuses To Join
  • Why?
  • US is 1 emitter of carbon dioxide
  • By ratifying, US GDP would seriously decline
  • Kyoto Protocol exempts China which upsets US
  • Questions global warmings real threat to the
    world and whether US ratifying would really help
    stop it
  • US does believe in the Kyoto principles and does
    a lot to help out the cause

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What can you do?
  • Discuss
  • Handout
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