Johan C. Varekamp Earth & Environmental Sciences Wesleyan University Middletown CT GLOBAL WARMING

Structure of this presentation 1. Global Warming-real or not? 2. Climate science, models and predictions

Source: OSTP

Source: IPCC TAR 2001 Variations of the Earth’s Surface Temperature* *relative to average

Hudson, Block Columbus Boston Massacre da Verrazano Vikings (Eric the Red) The Exploration of the West: Conditioned by climate change?

Collapse of the Larsen Ice Shelf near Antarctica - a piece of ice the size of Rhode Island came adrift

Melting of the Arctic and Antarctic Ice Caps

So these are the data: There 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 is: Natural Variability or the “Human Hand”?

THE GREENHOUSE EFFECT THE 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

Principles of terrestrial climate: Incoming solar radiation equals outgoing terrestrial radiation R sun = R terr The magnitude of R terr depends on T s (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

GREENHOUSE GASES: H 2 O, CO 2, CH 4, N 2 O, O 3, CFC CHANGES IN THE CONCENTRATIONS OF THE GREENHOUSE GASES OVER TIME?

Burning of fossil fuels Source: OSTP

Deforestation

ANTHROPOGENIC CARBON FLUXES IN THE 1990s: FOSSIL FUEL BURNING: 6 BILLION TONS CARBON/YEAR DEFORESTATION: 1.1 BILLION TONS CARBON/YEAR TOTAL: 7.1 BILLION TONS CARBON/YEAR WHERE IS ALL THAT CO 2 GOING??

Source: OSTP

Clear correlation between atmospheric CO 2 and temperature over last 160,000 years Clear correlation between atmospheric CO 2 and temperature over last 160,000 years Current level of CO 2 is outside bounds of natural variability Current level of CO 2 is outside bounds of natural variability Rate of change of CO 2 is also unprecedentedRate of change of CO 2 is also unprecedented Source: OSTP

If nothing is done to slow greenhouse gas emissions... If nothing is done to slow greenhouse gas emissions... CO 2 concentrations will likely be more than 700 ppm by 2100 CO 2 concentrations will likely be more than 700 ppm by 2100 Global average temperatures projected to increase between °F ( o C) Global average temperatures projected to increase between °F ( o C) 2100 Source: OSTP

MUCH OF THE CO 2 EMITTED INTO THE ATMOSPHERE DOES NOT STAY THERE - TAKEN UP BY PLANTS AND DISSOLVES IN THE OCEANS THE CARBON CYCLE!

Missing Carbon Predicted CO 2 increase from carbon emission records

How do we model future atmospheric CO 2 concentrations? Apply a carbon cycle model to a range of future Fossil Fuel Flux scenarios Use ‘economic scenarios’ that depend strongly on 1.Population growth rates 2.Economic growth 3.Switch to alternative energy technologies 4.Sharing of technology with the developing world

Carbon cycle model from E&ES 132/359 at Wesleyan University Symbols: M x = mass of carbon K x = rate constant FFF = Fossil Fuel Flux of Carbon Feedbacks: Bf = Bioforcing factor; depends on CO 2 (atm) K 4 = f(temperature)

To go from atmospheric CO 2 concentration change to climate change, we need to know the climate sensitivity parameter,. The common approach is:  T s =  F  or  F/  T s = 1/ where  F is the ‘radiative forcing’ caused by the increased CO 2 concentration. The value of  F can be calculated from the increase in CO 2 concentration using an integrated version of deBeers law.  T s is the change in the surface temperature of the earth ‘greenhouse modified’ We can solve for by taking the first derivative of the ‘greenhouse modified’ Boltzman’s Law F =  T s 4 or dF/dT s = 4F/T s leading to a 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 K/Wm -2, incorporating various positive and negative feedbacks.

(CO2 only!)

Global average temperature is projected to increase by 1.5 to 5.8 °C in 21 th century Projected warming larger than in SAR Projected rate of warming is high compared to the climate record Temperature Projections (TAR) Source: IPCC TAR 2001

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)

The Kyoto Protocol Main aim is to stabilize the concentrations of CO 2 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 CO 2 concentrations in 2012 would be about 1-2 ppm below non-treaty levels!

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.

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

WHICH OF THESE SYMBOLS WILL BE THE STRONGER ONE??

Could these be related? Greenhouse surprises and unexpected events

Evidence for very rapid climate change in the past: Younger Dryas cold period

The white colours are urban areas: high population density along western LIS

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 > 16,000 square miles LIS is 170 km long, 30 km wide, mean depth 20 m A source of food, recreation, and commerce

Environmental Issues in LIS Coastal Salt Marsh Degradation Seasonally Hypoxic Bottom Waters Metal Pollution Ecosystem Shifts

Regional Issues Eutrophication, Contamination, Invasive Species Global Issues Climate Change

SEA LEVEL RISE IN LONG ISLAND SOUND OVER THE LAST MILLENNIUM

Wheelers Marsh, Housatonic River, Milford, CT TODAY!

FUTURE??

Credit: Ron Rozsa

Two Connecticut Marshes

Ragweed pollen Onset of hatting industry Chestnut blight 137 Cs 210 Pb 14 C

Derive age model:

Mean High Water Rise curves (local)

RSLR curves, CT coast V+T, unpub data

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 TAR Sea-Level Rise Projections Source: IPCC TAR 2001

Long Island Sound has suffered from hypoxia for decades: Result of Global Warming? Eutrophication? It has always been like this…...

EAST LIS CENTRAL LIS WEST LIS NARROWS

Core locations for LIS studies

R/V UCONN

Sampling mud

 15 N ( o / oo ), C. perfringens (nr/gr), Hg (ppb)

MEASURES OF ORGANIC PRODUCTIVITY: BURIAL RATE OF ORGANIC CARBON BURIAL RATE OF DIATOM “SKELETONS” (BIOGENIC SILICA) PRODUCTION RATE OF HETEROTROPHS LIKE FORAMINIFERA

Elphidium excavatum

Paleo-temperature calculations from Mg/Ca in foram tests: (Mg/Ca) f = A10 BT 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

Core A1C1 MWPLIAMGW

DRY WET

The  13 C* value indicates the amount of oxidized C org that was added to the bottom water column. The  13 C* value serves as an indirect proxy for OCI or Oxygen Consumption Index (Level of Paleo Oxygenation)

MWP

% organic Carbon and  13 C* Year AD CORE A1C1

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 C org 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 well==> land use changes

Carbon isotopes became “lighter” since early 1800’s 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

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

CONCLUSIONS (2) 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 IMPACTS ON LIS:

CONCLUSIONS (3) Major environmental changes in the early 1800’s: increased C org and Bsi storage, isotopically lighter carbon, lower O 2 levels in bottom waters, sewage indicators, changed N sources and metal pollutants

CONCLUSIONS (4)

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.

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 1000’s of years The sea came into LIS around 10,000 years BP Native Americans settled around 12,000 years BP in CT