Fiction, Facts, Uncertainties,

1
Global Climate Change Fiction, Facts,
Uncertainties, Challenges Impacts David D.
Houghton Atmospheric Oceanic Sciences UW
Madison Email ddhought_at_facstaff.wisc.edu UW-Su
perior April 9, 2003
2
Lecture Outline

• Introduction
• What the unconvinced people are saying
• Facts
• Uncertainties
• Challenges
• Human impacts on climate change
• Climate change impacts on humans the
  environment
• What can we do about it?
• Concluding remarks

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• What the unconvinced people are saying
• Theory remains entirely unproved.
• One-in-three chance that experts are wrong.
• Models are incapable of handling water vapor.
• Troposphere should be warming faster than the
  surface.
• If the weather folk cant figure out whats
  happening
• for the rest of the week, how can they tell us
  what the climate will be for the next 50 years?
• 6. Guess what? Antarcticas getting colder,
  not warmer.
• 7. Global warming is still just a theory.

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• Facts
• Global mean temperature has been going up in the
  last 140 years.
• The magnitude of this variability does not exceed
  natural variability.
• Concentration of carbon dioxide has been going up
  as well as other greenhouse gases.
• Radiative theory of atmospheric gases
  (greenhouse) and aerosols is important.
• Climate change involves the entire earth system
  not just the atmosphere.
• 6. Future projections face uncertainties in
  emission production, modeling, and impacts.
• 7. Several thousand scientists from 40
  countries all over the world have been involved.

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Global Mean Temperature(140 year record)
Combined annual land-surface air and sea surface
temperature anomalies (C) 1861 to 2000 relative
to 1961 and 1990. Two standard error
uncertainties are shown as bars on the annual
number.
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Regional and Seasonal Temperature Trends
Temperature trends over 1977-2001
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1,000 Year Temperature and Instrumental Data

• 1.0
• 0.5
• 0.0
• 0.5

Northern Hemisphere anomaly (C) Relative to 1961
to 1990 mean
1000 1200
1400 1600
1800 2000
Year
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Overview of Past Climate Temperatures
2 x CO2
Temperature (K)
Decades
Millions of Years
Schematic comparison of possible future
greenhouse warming with estimates of past changes
in temperature. Pleistocene glacial-interglacial
cycles are more numerous than shown. The
characteristic amplitude of global temperature
change during glacial-interglacial cycles in 3-4
K. Note that pre-Pleistocene changes are not
well fixed in magnitude, but their relative
warmth is approximately correct. Maximum warming
in the Cretaceous is based on estimates by Barron
and colleagues.
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Carbon Dioxide
Indicators of the Human Influence on the
Atmosphere During the Industrial Era
(a) Global atmospheric concentrations of three
well mixed greenhouse gases
Methane
(b) Sulphate aerosols deposited in Greenland ice
Nitrous oxide
Sulphur
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Visible Radiation
Infrared Radiation
The Earths annual and global mean energy
balance. Of the incoming solar radiation, 49 is
absorbed by the surface. The heat is returned to
the atmosphere as sensible heat, as
evapotranspiration (latent heat) and as thermal
infrared radiation. Most of this radiation is
absorbed by the atmosphere, which in turn emits
radiation both up and down. The radiation lost to
space comes from cloud tops and atmospheric
regions much colder than the surface. This causes
a greenhouse effect.
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Global Climate System
Schematic view of the components of the global
climate system (bold), their processes and
interactions (thin arrows) and some aspects that
may change (bold arrows).
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Carbon Cycle in Earth System Components
Green Reservoirs Black Arrows
Fluxes
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• Uncertainties
• Human induced forcing changes to present
• Future emissions scenarios
• Special Report on Emission Scenarios (SRES)
  study
• A1FI fossil fuel intensive energy system
• A1T non-fossil fuel intensive energy system
• A1B no one energy source relied on
• A2 self-reliant economy, preservation of
  local identities
• B1 service and information economy, clean
  technology, global solutions
• B2 B1 with local solutions, increasing
  population, less technology
• Model predictions global mean
• Model predictions local conditions
• Impacts

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The Global Mean Radiative Forcing of the Climate
System For the year 2000, relative to 1750
Radiative Forcing (Watts per square metre)
Cooling Warming
Level of Scientific Understanding
15
Forcing Variations from 1770 to 2100
Forcing (Wm 2)
Year
16
Variations Among Models for one Emission Scenario
Global temperature change (C)
Precipitation
Years from start of experiment
Global precipitation change ()
Temperature
Years from start of experiment
17
Overall Predictions for Future Temperature
Change (global mean)
Temperature change (C)
Year
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Regional Control-Observed, Control-Double CO2
Winter, Temperature
Winter, Temperature
Control Observed
CO2 Control


Summer, Temperature
Summer, Temperature
Control Observed
CO2 Control
CNA Central North America SEA South East
Asia SAH Sahel SEU Southern Europe AUS
Australia NEU Northern Europe EAS East Asia



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Crop yields in SE Asia
-61 to 67 -50 to 30


Global Climate Change David D. Houghton
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Challenges A. Nature of climate system 1.
Analysis must consider entire climate system and
all of humanity 2.
Extensive natural climate variability 3.
Global connections for both climate forcing and
climatic response 4.
Uncertainties in outcomes involve uncertainties
in many components 5. A small
change in global means can translate to large
changes in local means/extremes B.
Needs for research 1. Improve data longer
data, error analysis, more global
coverage 2. Improve theory
radiation-aerosol, cloud drops-aerosol 3.
Improve models parameterization for small scale
components 4. Separating
naturally-induced fluctuations from human
effects C. Nature of people 1.
Implement controls on human impacts on the
environment 2. World cooperation 3. Look at
ourselves
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Separating Human from Natural Temperature Trends
0.1000 0.0100 0.0010 0.0001
OBSERVED 95th Percentile GFDL 95th Percentile
ECHAM 95th Percentile UKMO
Linear Trend (C yr-1)
0 20 40
60 80 100
Trend Length (years)
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Vertical Variations Footprint Zonal-Mean
Annual-Average Temperature (C)
Model Changed CO2
Pressure (hPa)
Model Changed CO2 Sulphur
Pressure (hPa)
Observed Changes
Pressure (hPa)
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• Uncertainties in Detection Attribution of
• Climate Change
• (Sept. 2002 paper Bull. Amer. Meteorological
  Society)
• Assessment by 19 experts (11 from the U.S.)
• Evidence type
• Century-long trend in global mean surface
  temperature
• 30-year trend in vertical pattern of temperature
• 30-year trend in geographical pattern of surface
  temp.
• 30-year trend in diurnal temperature range over
  land
• Mean assessment of probability of detection
• 95
• 99
• 80
• 73
• Mean expected fraction attributed to greenhouse
  forcing

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• Human Impacts on Climate Change
• 1. Types of impacts
• Focus on greenhouse gases primarily CO2
• Driving forces for the future
• Basic scenarios
• Scenario outcomes
• National and personal lifestyles (U.S.)

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• Types of Human Impacts
• Increase in greenhouse gases
• Increase in aerosols
• Change in surface conditions (e.g. albedo, wind,
  evaporation)
• Change in clouds(e.g. contrails, pollutants,
  etc.)

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Correspondence of O2 with CO2 Changes
O2 concentration, difference from standard (ppm)
CO2 concentration (ppm)
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Disposition of CO2 Added by Humans
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• Driving Forces for Future Human Impacts
• Population
• Economy (income per capita and regional
  differences)
• Technology
• a. Energy production fossil fuels and
  non-fossil fuels
• b. Energy use efficiency
• c. Land use
• Energy structure Coal Oil/Gas Renewables /
  Nuclear
• 5. Land use Forests Croplands Energy
  Biomass Other
• 
  
  (grasslands, etc.)
• 6. Agriculture

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SRES Scenarios for Emissions
30
Basic A Scenarios A1. Storyline and scenario
family describes a future world of very rapid
economic growth, low population growth, and the
rapid introduction of new and more efficient
technologies. Major underlying themes are
convergence among regions, capacity building, and
increased cultural and social interactions, with
a substantial reduction in regional differences
in per capita income. Technology subsets
are A1FI fossil fuel intensive energy
system A1T non-fossil fuel intensive energy
system A1B no one energy source relied on A2
Characterized by self reliant economy,
preservation of local identities. Storyline and
scenario family describes a very heterogeneous
world. The underlying theme is self-reliance and
preservation of local identities. Fertility
patterns across regions converge very slowly,
which results in high population growth.
Economic development is primarily regionally
oriented and per capita economic growth and
technological change are more fragmented and
slower than in other story lines.
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Basic B Scenarios B1. Characterized by a
service and information economy, clean
technology, and global solutions. The storyline
and scenario family describe a convergent world
with the same low population growth as in the A1
storyline, but with rapid changes in economic
structures towards a service and information
economy, with reductions in material intensity,
and the introduction of clean and
resource-efficient technologies. Emphasis is on
global solutions to economic, social and
environmental sustainability, including improved
equity, but without additional climate
initiatives. B2 Characterized B1 with local
solutions, increasing population, and less
technology. The storyline and scenario family
describe a world in which the emphasis is on
local solution to economic, social, and
environmental sustainability. It is a world with
moderate population growth, intermediate levels
of economic development, and less rapid and more
diverse technological change than in the B1 and
A1 storylines. While the scenario is also
oriented towards environmental protection and
social equity, it focuses on local and regional
levels.
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Population Projections
Population Projections Historical data from
1900 to 1990 (based on Durand, 1967 Demeny,
1990 UN, 1998, for medium) and IPCC IS92
scenarios (Leggett et al., 1992 Pepper et al.,
1992) from 1990 to 2100.
Global Population (billion)
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Economic Zones
OECD90 Developed Countries REF Economic
Reforming Countries ASIA Developing Countries
of Asia ALM Developing Countries
Elsewhere
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Economy GNP
Income per Capita by World and Regions (103 1990
US per capita)
Income per capita in the world and by SRES
region. Numbers in brackets give minimum and
maximum values of the SRES scenarios. The range
for 1990 illustrates differences in base-year
calibration across models.
2050
2100
Region 1990 A1
A2 B1 B2
A1 A2 B1
B2
OECD90 17.8-20.6 50.1
34.6 49.8
39.2 109.2 58.5
79.7 61.0
(39.4-62.3)
(32.3-54.0) (40.3-52.0) (35.1-42.2)
(69.8-115.7) (48.0-78.7) (70.6-84.7)
(50.1-73.2)
REF IND ASIA ALM WORLD
DEV 0.7-1.1 15.9
3.9 10.9
8.1 66.5 11.0
40.2 18.0
(11.4-16.7)
(3.3-5.1) (7.5-14.8)
(3.9-8.4) (41.4-69.8) (10.3-13.7)
(40.2-45.2) (14.2-21.5)
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Greenhouse Gas Emissions
N2O emissions (TgN)
CO2 emissions (GtC)
CH4 emissions (TgCH4)
SO2 emissions (TgS)
Year
Year
36
Global Energy Structure
Global primary energy structure, shares () of
oil and gas, coal, and non-fossil energy sources
historical development from 1850 to 1990 and in
SRES scenarios. Each corner of the triangle
corresponds to a hypothetical situation in which
all primary energy is supplied by a single source
oil and gas on the top, coal to the left, and
non-fossil sources to the right. Constant market
shares of these energies are denoted by their
respective isoshare lines.
Oil / Gas
Coal
Renewables/Nuclear
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Global Energy Resources
Global fossil and fissile energy reserves,
resources, and occurrences (in ZJ ( 1021J)).
Global and regional estimates are discussed in
detail in Rogner (1997) and Gregory and Rogner
(1998).
Global renewable energy potentials for 2020 to
2025, maximum technical potentials, and annual
flows (in EJ (1018 J)).
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Estimated Net Energy Use in USA in 1972



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Transportation Energy Efficiency USA Study 1974
Passenger
Freight
Urban
Intercity
Transportation energy efficiency. All
efficiencies shown are expressed in terms of
gasoline equivalent (125,000 Btu/gal
34,839,536.62 kJ m 3 ).
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• Climate Change Impacts on Humans the
  Environment
• A. Terrestrial ecosystems
• Agriculture
• Forests
• Desert and desertification
• Hydrology and water resources
• Ocean systems
• 1. Sea level
• 2. Coastal zones and marine ecosystems
• Human systems
• Settlements, energy and industry
• Economic, insurance, and other financial services
• Human health
• Vector borne diseases
• Water-borne and food-borne diseases
• Food supply
• Air pollution
• Ozone and ultraviolet radiation

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Agriculture in Latin America
Yield Impact ()
decrease increase increase decrease -30 -40 to
30 -50 to 15 -25 to 2 -10 to
40 -20 -24 -61 -61 to 6 -36 to 17 -5 to
10 increase-decrease -16 to 2 -8 to 7 -8
to 13 -22 to 21 -10b -8 to 5c -15d -13 to
10c
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Water Availability Resources
Water availability in 2050 for the present
climatic conditions and for three transient
climate scenarios. (m3 / year / person)
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Sea Level Rise Impacts
1.0 0.1 17.5 8.4 0.2 - 1.0 1.1 0.4 0.6 12.5 2.1 8
0 0.3 5.9 2.0 0.5 3.1 1.4 2.9 0.3 0.1 0.6
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Vector-Borne Disease Susceptibility
Likelihood of Altered Distribution with Climate
Change


Major tropical vector-borne diseases and the
likelihood of change of their distribution with
climate change.
likely very likely highly likely ?
unknown
45
Temperature Indicators
Schematic of observed variations of various
temperature indicators.
46
Hydrological and Storm Indicators
Schematic of observed variations of various
hydrological and storm-related indicators.
47
Atlantic Tropical Storm Variability
Annual Number of Atlantic Hurricanes (solid
bar) And Tropical Storms (open bar)
Time series of the annual number of Atlantic
tropical cyclones reaching at least tropical
storm strength (open bar) and those reaching
hurricane strength (solid bar) for 1886-1988.
The average numbers of tropical storms and
hurricanes per year are 8.4 and 4.9,
respectively.
48

• Human Responses to Climate Change
• Why should we care?
• Modify our own life style
• Mitigation and adaptation
• Modify national and global practice
• Influencing public policy

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• Why Should We Care?
• We dont know exactly what will happen with
  global warming or what the impacts will be. And
  where or when they will hit hardest.
• But scientists have a pretty good general idea
  of whats to come. They tell us the possible
  impacts could be far-reaching and could cause
  serious problems
• Sea level will continue to rise, eroding beaches
  and increasing the damage from storms and leading
  to loss of wetland habitats. Some island nations
  will disappear.
• Increasing temperatures are likely to affect
  human health
• Warmer temperatures mean mosquitoes will spread
  in areas that were previously too cold for them
  to survive. Mosquitoes carry infectious diseases
  like malaria and encephalitis.
• Ground-level ozone pollution will likely worsen,
  increasing respiratory diseases like asthma.
• Deaths from heat waves will rise.
• Some plants and animals may face extinction if
  habitat changes.
• Changing weather patterns could affect
  agriculture. Northern states could actually
  experience longer growing seasons. The U.S.
  Great Plains could have frequent droughts.

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• What Can We Do About Global Warming?
• There are simple steps each of us can take that
  will help reduce our emissions of greenhouse
  gases.
• Just a few examples
• Recycling saves the energy required to
  manufacture new products.
• Give your family car a day off by riding your
  bike, taking the bus, or walking.
• Plant trees they absorb carbon dioxide.
• Read and learn about global warming.
• Save electricity by turning off the TV and
  lights when youre through with them.
• Go solar a solar system to provide hot water
  can reduce your familys carbon emissions by
  about 720 pounds a year.
• Encourage others to take these simple actions.
• Preserve forests they act as carbon dioxide
  sinks in other words, they absorb carbon
  dioxide.

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Mitigation and Adaptation Diagram from SRES
CLIMATE CHANGE Including Variability
Human Interface
Exposure
Initial Impacts or Effects
MITIGATION Of Climate Change via GHG Sources and
Sinks
Vulnerabilities
Impacts
Autonomous Adaptations
Planned ADAPTATION to the Impacts and
Vulnerabilities
Residual or Net Impacts
Policy Responses
Places of adaptation in the climate change issue.
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Recent Reductions in Chinas Greenhouse Gas
Emissions
Focusing only on CO2 emissions form fossil fuel
combustion, against which we can compare other
countries, we calculate that Chinas emissions
dropped from 2950 Tg (teragrams of CO2, 1 Tg 1
million tonnes) in 1996 to 2690 Tg in 2000, a
reduction of 8.8. This decrease, which China
achieved while most other countries were
increasing their emissions, represents about 1
of the global CO2 emissions from fossil fuel
combustion in 2000 of 25,300 Tg. In the period
1995 to 1999, CO2 emissions form fossil fuel
combustion in western Europe increased by 4.5,
in the United States by 6.3, in Japan by 3.0,
and in India by 8.8.
Trends in emissions of (A) CO2 and (B) CH4 in
China, 1990 to 2000.
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• Concluding Remarks
• Research activities continue to increase
• - North American Carbon Program
• - Climate modeling enhancement
• - Regional climate change studies
• U.S. Government Plans
• - Enhanced support for research
• (13 Federal agencies involved)
• - Research technology to help in mitigation
  (e.g. Hydrogen car)
• - Support Earth Observation Summit
• (July 31, 2003)
• 3. Were on a LONG road