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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