Post on 15-Apr-2017
Gathering and analysing climate change data 1 ) Observed climate1.) Observed climate2.) Modelled climate
At (a) Regional (b) National and (c)At (a) Regional (b) National and (c) Destinational scale
Use data to identify potentialUse data to identify potential impacts and vulnerabilities on Eleuthera
Making a climate change data bank available for further impacts studiesimpacts studies
Is there evidence of long-term trends in the
What are the characteristics of current
What year-to-year or decade-to-decade variations are seen in
climate in recent decades?
of current climate? ‘normal’ or current
climate? E.g. El Nino....
◦ Observations 1900-2009...◦ Mainly records from weather◦ Mainly records from weather
stations, but also Satellite data in recent years... y
• Projections of the future from Global or Regional climate modelsRegional climate models
1. Emissions
2. GCMSimulated Climate
3. DownscalingLocal Climate
4. ImpactsScenarios Climate
ResponseLocal Climate
responseImpacts
Hypothetical, but plausible, scenarios of global socio-economic h ‘Wh t ill h t th li t if ’change. ‘What will happen to the climate if...’
Estimate carbon emissions based on different scenarios of societal change e.g. attitudes, population, technological developments
A2A1Bd
B1A2high emissions
(high population growth, strong emphasis on
economic development)
medium emissions (rapid economic growth but with
decreasing reliance on fossil fuels)
low emissions (a more environmentally
sustainable approach, lower consumption and lower
population growth.)) population growth.)
AtmosphereCloud Types
RadiativelyActive
gases and Horizontal exchange between columns of momentum, heat and moistureAtmosphere
Vertical exchange Run-off
L d h Di l d
Ice
gaerosols
↓ Precipitation
Sea
Momentum, latent and
sensible heat fluxes
Biosphere
gbetween layers of momentum, heat and moisture
Land heat and moisture storage
Diurnal and seasonal
penetration
Sea Ice
Surface Ocean Layers
2 How2 How Land surfaceE.g. Topography, Hydrology, Ice Sheets, Vegetation cover
2. How2. Howdoes a does a GCMGCM
g
O L
GCM GCM work?work? Ocean Layers
Vertical exchange of water, heat, salt, nutrients... Ocean layers
Horizontal exchange of water heat salt
work?work?
of water, heat, salt, nutrients etc
• Simulate the large scale gglobal circulation patterns that determine climate
• Cannot represent fully the topography –mountains, lakes etc
• cannot simulate land-sea interactions, sea breezebreeze
• Cannot resolve many important physical processes at this coarse resolution e.g. Storms/hurricanesStorms/hurricanes.
PRECIS - driven by 2 different GCMS (ECHAM-4 and HadCM3) INSMET, CCCCC and UWI.
‘Downscale’ to 50km and 25km spatial resolutions
Model a smaller regions, given ‘boundary conditions’ from a GCM
h l llHigher resolution allows more realistic representation of physical processes
Ensemble of Regional Gridded 15 IPCC GlobalModels
Regional Model Projections
RegionalScale
Griddedobservational
datasets
Ensemble ofNational
ScaleGridded
observationaldatasets
Ensemble of 15 IPCC GlobalModels
Regional Model Projections
Models
Destination Scale
Local Observation
Stations Regional Model
Projections(where available)
Observed increase 0.11˚ per decade
2030
2090s
(+2 3) +3 1˚(+3 5)2030s
(+0.6) +0.9˚(+1.2)
(+2.3) +3.1 (+3.5)
The Bahamas: ‘Hot’ daysThe Bahamas: ‘Hot’ daysyy
2060s(26) 40% (47)
2090s(36) 59% (67)
)
No clear trend in recent observed data
2030s(-13) -4 % (+10)
2090s(-30) -7 % (+18)
2090s
Primary Climate VariablesyTemperature, Precipitation, Evaporation ,Humidity, Wind speed, Sea Surface Temperature, Cloud cover (sunshine hours)Hurricane frequency and intensity, Sea-Level riseHurricane frequency and intensity, Sea Level rise
h l dPhysical Impacts and Vulnerabilities
Human healthAgriculture and fisheries
Linking VariablesStorm SurgeWater quality and availability Agriculture and fisheries
Run-off and soil erosionBiodiversity and habitat loss
Water quality and availabilityOcean acidityFlooding – from coasts or heavy rainfallCoastal erosionCoastal erosion
Vulnerabilities in the Tourism
SectorSector
IPCC estimate of 0.13-0.56 metres in the Caribbean by the 2090s relative to 1980-1999...
S l l i Th l E i f O I◦ Sea-level rise = Thermal Expansion of Oceans + Ice Sheet/Glacier Melt
◦ However: Recent research suggests that ice sheet melt might accelerate over the coming decades, and not to continue at the current rate and that IPCC estimates mightcontinue at the current rate, and that IPCC estimates might underestimate future sea-level rise.
◦ Several independent studies* indicate higher sea-level rise f 1 5 b h 2090of up to 1.5m by the 2090s.
* e.g. Rahmstorf 2007, Rignot et al, 2008, Rohling et al, 2008g , g , , g ,
Climate change and sea-level irise:◦ Shift in shore line◦ Exacerbated coastal erosion
E h d h i h◦ Enhanced storm surge heightsWhat is the observed rate of shoreline recession? ◦ Compare current shoreline
position with aerial photography and satellite archives
What might be the future position of the shoreline?◦ Overlay sea-level rise scenarios
onto topography◦ Identify most vulnerable regions
Ryan Sim, Josh King (Univ. Waterloo)S R ll (B h D M l )Suzanne Russell (Bahamas Dept. Meteorology)Carol McSweeney (Univ. Oxford)With help from Lionel Fernander
Storms and HurricanesStorms and HurricanesIPCC AR4: ‘Tropical storm and hurricane frequencies vary considerably from year to year, but evidence suggests substantial increases in intensity and duration since the 1970s.’
Estimating future changes in storm characteristics
IPCC AR4 Summary: ‘a likely increase of peak wind
intensities and notably whereintensities and notably, where analysed, increased near-storm precipitation in future tropical cyclones’
Storms are hurricanes operate on too small a scale to be resolved by global or regional climate models
◦ Studies based on high resolution weather models and statistical models
Storm surge model◦ Review literature to make estimates
of changes in intensity, duration, hurricane season length, and path.
Storm surge model• Add storm surge to Digital Elevation ModelModel
Carol.McSweeney@ouce.ox.ac.ukCarol.McSweeney@ouce.ox.ac.uk
R lt f b dd d hi h l ti d l dResults from embedded high-resolution models andglobal models, ranging in grid spacing from 100 km to 9 km,project a likely increase of peak wind intensities and notably,where analysed increased near storm precipitation in futurewhere analysed, increased near-storm precipitation in futuretropical cyclones. Most recent published modelling studiesinvestigating tropical storm frequency simulate a decrease inthe overall number of storms though there is less confidencethe overall number of storms, though there is less confidencein these projections and in the projected decrease of relativelyweak storms in most basins, with an increase in the numbers ofthe most intense tropical cyclonesthe most intense tropical cyclones.
Tropical storm and hurricane frequencies vary considerably from year to year, but evidence suggests substantial increases in yea to yea , but e de ce suggests substa t a c easesintensity and duration since the 1970s.In the extratropics, variations in tracks and intensity of storms reflect variations in major features of the atmospheric circulation, such as the North j p ,Atlantic Oscillation.
Temperature (minimum, mean, maximum)Rainfall (total, intensity, number of rainy days, timing of seasonal rainfall, length Directly y , g , gof dry spells)HumiditySea-surface temperatures
projected from climate
modelsSea surface temperaturesWind speed Cloud cover (sunshine hours)
Sea-level rise Water - Quality and availabilityStorm surge incidenceStorms and Hurricanes: Frequency, intensity, paths, and timing
Ocean AcidityFlooding – Surface and CoastalCoastal Erosionintensity, paths, and timing Coastal Erosion