IPCC Caribbean Climate Change Conclusions

Professor Anthony Chen

IPCC Caribbean Climate Change Conclusions

Climate Change ConferenceUWI, Mona

June 1-17,2007

A. Anthony ChenClimate Studies Group, Mona

Department of PhysicsUniversity of the West Indies, Mona

Advisory Report on Global Change: global warming …no… big…deal…have…a…nice…day…

Why Worry about Greenhouse Gases?

Greenhouse Gases in Atmosphere

Water vapor, Carbon Dioxide, Nitrous Oxide, Methane, Oxygen, Ozone, Chlorofluro-carbons Naturally occurring and man made

They trap the radiant heat from earth, making the earth warmer Greenhouse effect, similar to horticultural

greenhouse

We need the greenhouse effect

Without naturally occurring greenhouse gases Earth’s temperature would be about 33ºC Colder

Need nearly constant amount of CO2 …But …

Last ice age

CO

2 Concentration (ppm

v)

CO2 Concentration in Ice Core

Years before Present400,000 100,000

Projected 2100

2001

Too much: Runaway Greenhouse effect – CO2 and H2O Vapour

H2O vapourGreenhouse Effect

Increased Air Temperature Evaporation

Increased CO2

Venus is almost the same size as the Earth but completely uninhabitable. A runaway greenhouse effect makes the surface 400 degrees hotter than the Earth.

Venus Earth

Working Group I assesses the scientific aspects of climate change. Working Group II assesses impacts, vulnerability and adaptation

Working Group III assesses options for mitigating climate change.

Founded 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP)

IPCC Assessment Reports

1990: First Assessment Report (FAR)1995: Second Assessment Report (SAR)2001: Third Assessment Report (TAR)2007: Fourth Assessment Report (AR4)

Contents of AR4

Chapter 11

Includes section on small islands for first time: Caribbean, Indian Ocean, North and South Pacific Oceans

Processes to Reduce Uncertainties in Chapter 11

Climate (average state of weather), not day to variation in weather

Assessment based on peer reviewed papers and publications up to March 2006 Observed trends in climate Global Circulation Models of Climate Downscaling of global models

Regional climate models (dynamic)Statistical downscaling

Strong Physical basis or explanation Greater degree of certainty when more of the

above agree

Special Report on Emission Scenarios (SRES)

CO

2 Em

issions

2000 2100

A2

A1B

B1

AR4 Summary Statement for Caribbean region based on limited Peer Reviewed Papers and Data:

Sea levels will likely continue to rise on average during the century around the islands of the Caribbean Sea. (Models indicate that the rise will not be geographically uniform globally but large deviations among models make estimates of distribution across the Caribbean, Indian and Pacific Oceans uncertain.)

All Caribbean islands are very likely to warm during this century. The warming is likely to be somewhat smaller than the global, annual mean warming in all seasons.

Rainfall in the vicinity of the Greater Antilles is likely to decrease in JJA but changes elsewhere and in DJF are uncertain.

Likely: > 66%Very likely > 90%

Rest of Presentation

Some details of projection for the Caribbean (Chapter 11)

Global Projections (Chapter 10 ) which may affect the Caribbean– Hurricanes, ENSO, NAO, Sea level rise

Others more recent research (non-AR4) CSGM Regional Downscaling using PRECIS

Limitations (Needs)

AR4 Assessment of Observed Caribbean Temperature Change

Peterson and Taylor, et al, 2002:Journal of Geophysical ResearchSignificant warming trend

from1950’s to 2000Based on UWI Climate Data

workshop in 2001

All models give temperature rises for all months

AR4 Assessment of temperature Change•21Global Models using SRES A1B Scenario:•Monthly Increases projected to 2090

Tem

perature Change ºC

2ºC

Jan Dec

25%

50%

25%

Average

Global model results Supported by the work of Angeles et al, 2007, at U. of Puerto Rico, Mayaguez

AR4: Statistical Downscaling: Piarco Airport (T&T) Temperature projected statistically from 1960-1990 to 2080’s using A2(Cassandra Rhoden, MPhil thesis, UWI, Mona)

Global and downscaled projected changes agree. Similarly for Worthy Park, Jamaica and Grantley Adam, Barbados

1960-90 2080

Tem

p ºC 2ºCGlobal Statistical

A2 B2

Post AR4 Dynamic Downscaling: Regional model simulated changes in temperature by 2080’s based on 1960 – 1990 data (Jayaka Campbell, MPhil thesis, UWI, Mona)

3ºC 2ºC

Strong Physical Basis for temperature increases: Man made greenhouse gases increases the amount of heat trapped by the atmosphere:

Virtually certain that Caribbean temperatures will increase

Extent will depend on actual green house gas emissions

•Even if emissions ceased today temperatures will rise at the end of the century due to long lifetimes of CO2 and methane and long ‘memory’ of the oceans

•Agreement of observation, global models, statistical downscaling, good physical basis

~ 2ºC for A1B scenario, ~ 3ºC Globally

% C

hange

-50

+50

21

0

No. of m

odels increasingAR4 Assessment of 21 Global Models’ Projection of Changes in Precipitation from 1980’s to 2080’s using A1B Scenario

Significant decrease in JJA

Large number of models showing decrease

Annual Dec-Feb Jul-Aug

AR4 Assessment: Monthly Precipitation Change over the Caribbean from 21 models using AIB from 1980’s to 2080’s

Jan DecP

ercentage Change

25% models give increases

Most models decrease in Jun to Aug

Increases

Decreases

Precipitation SummaryExpect drying in the Greater Antilles in JJA

General Agreement between Global ModelsA Global model run for the Caribbean show

decrease in JJA (Angeles et al, 2007)Some statistical runs show decreases in JJADrying trend in observed data (Neelin et al.,

2006) Theoretically, drying is probable in Greater

Antilles (Chou and Neelin,2004) **

Near the equatorAdjacent region:

Lesser Antilles Greater Antilles

Convective adjustment

-Rising air due to CO2 induced heating

Reduced Rising

Moisture moves in because of adjustment - wetter

Moisture moves out - drier

Simplified Mechanism – Wet Gets Wetter

Most model agree in JJA

Some models do not agree

Precipitation SummaryExpect drying in the Greater Antilles in JJA

General Agreement between Global ModelsA Global model run for the Caribbean show

decrease in JJA (Angeles et al, 2007)Some statistical runs show decreases in JJADrying trend in observed data (Neelin et al.,

2006) Theoretically, drying is probable in Gtr Antilles

(Chou and Neelin, *•Not enough results to make statement for rest of Caribbean and rest of the year

Other Results Supporting drying:

North Atlantic Oscillation (NAO) In multimodel analysis, NAO increases

El Niño Model consensus gives El Niño like pattern with

higher temperatures in the eastern Pacific.

These conditions are associated with drying in the Caribbean.

North Atlantic Hurricanes

Observations an increasing trend in the frequency and

duration of North Atlantic hurricane significant at the 99% confidence level (Webster et al., 2005: Science, 309: 1844-

1846).

20 Km Japanese model result of Hurricane tracks (Oouchie et al, 200)

Actual (observed) tracks 1979-1988

Simulated Present day tracks

Simulated Future tracks (2080-2099)

Greater density

Not EnoughNot enough results to make statement

about the Caribbean hurricanesNOAA, 2006: Observed increases can

also be explained by natural variability (as opposed to anthropogenic induced variability)

Anthropogenic influence: You are invited to attend Dr. Holland’s lecture tomorrow for more information at 6 pm, Social Science Lecture Theatre

Sea Level Rise Observation

The rise in the Caribbean appears to be near the global mean (Church et al, 2004: J. Clim., 17, 2609-2625).

1.8 ± 0.3 mm per year or 0.18m per 100year over the period 1950– 2000.

Modelling Large deviation among models No regional modelling Global mean rise expected: 0.2 to 0.5 m up to 2090’s

No enough to make IPCC statement for the Caribbean

IPCC AR4 Statement for Caribbean based on limited Peer Reviewed Papers and Data: Sea levels will likely continue to rise on average

during the century All Caribbean islands are very likely to warm

below the global average during this century. Rainfall in the vicinity of the Greater Antilles is

likely to decrease in JJA but changes elsewhere and in DJF are uncertain.

Other non-IPCC projections based on limited data•Frequency and intensity of hurricanes in the North Atlantic will probable increase•Sea level rise in the Caribbean will probable follow global trend

Limitations to knowledge of Caribbean Climate Change

Global models do not see islands, except …Little dynamic and statistical downscaling.Many Caribbean climatic processes not well

understood.Insufficient model runs to determine regional

distribution of cyclone changes.Uncertainty about future El Niño. Large deviations among models make

regional distribution of sea level rise uncertain.

Limited number of storm surge models.

Den Why dem no use TUMS fi get rid of the gas!

How can we fix the problem?

No quick or easy fixes Mitigation

Alternative and new sources of energy

UWI Physics Students wiring a solar panelMunro Wind turbine

No quick or easy fixes

No Mitigation Point of no return (Runaway Greenhouse

effect)?

No quick or easy fixes

Adaptation Impact studies

E.G., Study of impact of Climate Change on Biodiversity

Need to reduce uncertainties about climate Much More research

needed To be able to

predict day by day weather

To predict future climate change

With others Tackling Climate

Change and Getting ready for 5th IPCC Assessment

Climate Studies Group, Mona (CSGM)

What we must do is see the whole world as our “self”

Only then will we be worthy

of being entrusted with the World (Earth)

Only One who values the World as his own body

can truly rely on the World in return.

Lao Tsu, over 2000 years ago

FINIS