Johan C. Varekamp

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GLOBAL WARMING

• Johan C. Varekamp
• Earth Environmental Sciences Wesleyan
  University
• Middletown CT

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Structure of this presentation1. Global
Warming-real or not?2. Climate science, models
and predictions
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Source OSTP
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Variations of the Earths Surface Temperature
relative to 1961-1990 average
Source IPCC TAR 2001
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The Exploration of the West Conditioned by
climate change?
Vikings (Eric the Red)
da Verrazano
Columbus
Hudson, Block
Boston Massacre
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Collapse of the Larsen Ice Shelf near
Antarctica - a piece of ice the size of
Rhode Island came adrift
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Melting of the Arctic and Antarctic Ice Caps
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So these are the dataThere is global warming,
ice is melting, glaciers are retreating, rainfall
patterns are changing, plants and animal species
are moving, sea level is rising.The real BIG
question isNatural Variability or the Human
Hand?
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THE GREENHOUSE EFFECTTHE SUN EMITS SHORT
WAVELENGTH RADIATION (VISIBLE LIGHT) WHICH
PENETRATES THROUGH THE ATMOSPHERE AND HEATS THE
SOLID EARTH.THE SOLID EARTH EMITS LONG WAVE
LENGTH RADIATION (INFRA RED) WHICH IS ABSORBED
ON ITS WAY OUT BY THE GREENHOUSE GASES.A
THERMAL BLANKET IS THE RESULT
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Principles of terrestrial climate Incoming solar
radiation equals outgoing terrestrial
radiation Rsun Rterr The magnitude of Rterr
depends on Ts (Boltzman Law). Part of the
outgoing terrestrial radiation is blocked by
greenhouse gases, and the earth warms up a bit to
restore the radiative equilibrium
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GREENHOUSE GASESH2O, CO2, CH4, N2O, O3, CFC

• CHANGES IN THE CONCENTRATIONS OF THE GREENHOUSE
  GASES OVER TIME?

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Burning of fossil fuels
Source OSTP
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Deforestation
Source OSTP
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ANTHROPOGENIC CARBON FLUXES IN THE 1990s FOSSIL
FUEL BURNING 6 BILLION TONS CARBON/YEAR DEFORESTA
TION 1.1 BILLION TONS CARBON/YEAR TOTAL 7.1
BILLION TONS CARBON/YEAR WHERE IS ALL THAT CO2
GOING??
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Source OSTP
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• Clear correlation between atmospheric CO2 and
  temperature over last 160,000 years
• Current level of CO2 is outside bounds of
  natural variability
• Rate of change of CO2 is also unprecedented

Source OSTP
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• If nothing is done to slow greenhouse gas
  emissions. . .
• CO2 concentrations will likely be more than 700
  ppm by 2100
• Global average temperatures projected to
  increase between 2.5 - 10.4F (1.4 - 5.8 oC)

2100
Source OSTP
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MUCH OF THE CO2 EMITTED INTO THE ATMOSPHERE DOES
NOT STAY THERE - TAKEN UP BY PLANTS AND DISSOLVES
IN THE OCEANSTHE CARBON CYCLE!
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Predicted CO2 increase from carbon emission
records
Missing Carbon
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How do we model future atmospheric CO2
concentrations?

• Apply a carbon cycle model to a range of future
  Fossil Fuel Flux scenarios
• Use economic scenarios that depend strongly on
• Population growth rates
• Economic growth
• Switch to alternative energy technologies
• Sharing of technology with the developing world

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Carbon cycle model from EES 132/359 at Wesleyan
University Symbols Mx mass of carbon Kx
rate constant FFF Fossil Fuel Flux of
Carbon Feedbacks Bf Bioforcing factor
depends on CO2(atm) K4 f(temperature)
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To go from atmospheric CO2 concentration change
to climate change, we need to know the climate
sensitivity parameter, l. The common approach
is DTs l DF or DF/DTs 1/l where DF is the
radiative forcing caused by the increased CO2
concentration. The value of DF can be calculated
from the increase in CO2 concentration using an
integrated version of deBeers law. DTs is the
change in the surface temperature of the
earth We can solve for l by taking the first
derivative of the greenhouse modified
Boltzmans Law F t sTs4 or dF/dTs 4F/Ts
leading to a l value of 0.3 K/Wm-2. That value
equals 0.27 K/Wm-2 for an earth with similar
albedo but no atmosphere (no greenhouse). This
approach is the most fundamental response
function and uses zero climate feedbacks! Climate
models use 0.3 - 0.9 K/Wm-2, incorporating
various positive and negative feedbacks.
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(CO2 only!)
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Temperature Projections (TAR)

• Global average temperature is projected to
  increase by 1.5 to 5.8 C in 21th century
• Projected warming larger than in SAR
• Projected rate of warming is high compared to the
  climate record

Source IPCC TAR 2001
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If we continue as we have done for the last 100
years (business-as-usual scenario), we will be
looking at a much warmer earth, with many
unpredictable side effects (sea level, extreme
events, changes in carbon cycle -methane in
tundras, methane in clathrates, etc)
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The Kyoto Protocol

• Main aim is to stabilize the concentrations of
  CO2 and the other GHG in the atmosphere through
  reductions in carbon emissions
• Direct Goal reduce carbon emissions by
• 5 below 1990 emission levels in 1012
• Uses trading of carbon pollution units as an
  incentive for the economically least painful way
• Net effect would be that atmospheric CO2
  concentrations in 2012 would be about 1-2 ppm
  below non-treaty levels!

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141 countries have ratified the treaty (55 of
the carbon emissions), with the big absences in
the western world being the USA (20 of the
carbon emissions) and Australia. Large carbon
contributors from the emerging economies (but
growing fast!) are China, India and Brazil, which
are exempt from the protocol.
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The Kyoto protocol is not the wisdom of
scientists nor the folly of the greens, but shows
the courage of progressive politicians to work on
the future of our planet - one small step at a
time
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WHICH OF THESE SYMBOLS WILL BE THE STRONGER ONE??
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Could these be related?
Greenhouse surprises and unexpected events
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Evidence for very rapid climate change in the
past Younger Dryas cold period
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The white colours are urban areas high
population density along western LIS
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• Estuary of National Importance
• The Urban Sea more than 28 million people live
  within a one-hour drive from its shores
• LIS contains over 18 trillion gallons of water
• LIS watershed gt 16,000 square miles
• LIS is 170 km long, 30 km wide, mean depth 20 m
• A source of food, recreation, and commerce

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Environmental Issues in LISCoastal Salt Marsh
DegradationSeasonally Hypoxic Bottom
WatersMetal PollutionEcosystem Shifts
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Regional Issues Eutrophication,
Contamination,Invasive SpeciesGlobal
IssuesClimate Change
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SEA LEVEL RISE IN LONG ISLAND SOUND OVER THE
LAST MILLENNIUM
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Wheelers Marsh, Housatonic River, Milford, CT
TODAY!
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FUTURE??
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Credit Ron Rozsa
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Two Connecticut Marshes
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137Cs
Chestnut blight
210Pb
Onset of hatting industry
Ragweed pollen
14C
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Derive age model
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Mean High Water Rise curves (local)
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RSLR curves, CT coast
VT, unpub data
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TAR Sea-Level Rise Projections

• Global average sea level is projected to rise by
  10 to 88 cm between 1990 and 2100
• Projected rise is slightly lower than the range
  presented in the SAR (15 to 93 cm)
• Sea level will continue to rise for hundreds of
  years after stabilization of greenhouse gas
  concentrations

Source IPCC TAR 2001
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• Long Island Sound has suffered
• from hypoxia for decades
• Result of Global Warming?
• Eutrophication?
• It has always been like this...

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Core locations for LIS studies
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R/V UCONN
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Sampling mud
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d15N (o/oo), C. perfringens (nr/gr), Hg (ppb)
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• MEASURES OF ORGANIC PRODUCTIVITY
• BURIAL RATE OF ORGANIC CARBON
• BURIAL RATE OF DIATOM SKELETONS (BIOGENIC
  SILICA)
• PRODUCTION RATE OF HETEROTROPHS LIKE FORAMINIFERA

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Elphidium excavatum
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Paleo-temperature calculations from Mg/Ca in
foram tests

• (Mg/Ca)f A10BT
• The parameters A and B are empirically fitted
  with core-top samples to obtain a mean annual
  modern LIS bottom water temperature of 12.5 C
• The mixing model suggests that (Ca/Mg)w is not
  salinity-sensitive in the range of modern LIS
  salinities

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Core A1C1
MWP
LIA
MGW
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WET
DRY
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The d13C value indicates the amount of oxidized
Corg that was added to the bottom water
column. The d13C value serves as an indirect
proxy for OCI or Oxygen Consumption Index (Level
of Paleo Oxygenation)
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MWP
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organic Carbon and d13C
CORE A1C1
Year AD
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Observations

• Since 1850 increase in pollutants (Hg), sewage,
  different N sources, and increased foram
  productivity
• Carbon storage in LIS sediments has increased by
  4-5X in the last 150 years. Higher Corg burial
  rates in Western LIS compared to Central and East
  LIS
• E-W gradient in BSi about 2.5 in Central LIS,
  up to 4.5 in WLIS. Biogenic Silica storage also
  increased over the last 150 years
• Sediment accumulation rates increased
  several-fold as wellgt land use changes

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Carbon isotopes became lighter since early
1800s which is mainly the effect of increased
organic carbon burdens (and oxidation), minor
salinity effects Hypoxia may have occurred for
200 years but no evidence for hypoxia in central
LIS prior to 1800!! Anthropogenic
Effect! Temperature record conform known climate
trends
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CONCLUSIONS (1)

• Global warming is here! Its effects have been
  documented extensively worldwide
• The human hand is, according to many, very
  visible
• Projections for the future are riddled with
  uncertainties, but all show further warming

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CONCLUSIONS (2)
IMPACTS ON LIS

• Paleo-temperature record in LIS since 900 AD
  shows MWP, LIA and evidence for MGW
• Highest salinity in LIS occurred during the MWP,
  lowest during the LIA
• Possibly more salinity variability in the 20th
  century

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CONCLUSIONS (3)
Major environmental changes in the early
1800s increased Corg and Bsi storage,
isotopically lighter carbon, lower O2 levels in
bottom waters, sewage indicators, changed N
sources and metal pollutants
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CONCLUSIONS (4)

• Hypoxic events may have occurred since the early
  1800s but were absent before that time. They are
  severe in the late 20th century. Why?
• Enhanced productivitygt more Corg
• Modern global warminggt higher rate of Corg
  decompositon and increased water stratification
• HYPOXIA NEED A COMBINATION OF HIGH BWT AND HIGH
  Corg LOADING

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Work done with funding from the CT SeaGrant
College Program, EPA and the CTDEP-administered
Lobster Research Fund and efforts by many
Wesleyan University students.
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The early history of LIS (according to JCV) Long
Island is a moraine pushed up by the glaciers and
LIS is a depression sitting in front of that
pile of material When the glaciers started
melting (20,000 years BP), LIS filled with fresh
water forming Glacial Lake Connecticut Glacial
Lake Connecticut drained around 16,000 years BP
and LIS was dry for 1000s of years The sea came
into LIS around 10,000 years BP
Native Americans
settled around 12,000
years BP in CT