unitii-global-hazard-trends-160927173147.pdf

global and national hazard trends

2. Hazard trends -Cumulative
Hazard trends, 1900–2005

3. Interpretations
•Part of this rise is likely to be due to more accurate
recording and better communications with isolated
regions.
•Note the rapid rise since around 1960, when
satellite remote sensing and global
communications began.
•Population growth has led to more people living in
potentially hazardous locations. This means there
are greater numbers at risk.
•Many of these people at risk live in the developing
world, and are vulnerable due to their low coping
capacity.

4. Hazard trends
Number of natural disasters by type, 1970–2005

5. Interpretations
•Some types of disaster show clearer trends than others.
•The graph on the last slide compares trends in three disaster
types.
•The trend for earthquakesis fairly stable. There is no
evidence that the number of earthquake events is increasing.
There are likely to have been more people in earthquake-
prone areas in 2000 than in 1980, and this would explain the
slight rise in disasters.
•There is a clearer upward trend for floodsand wind storms.
This may indicate an increase in the vulnerable population and
a rise in the number of hazardous events.
•It could be the result of global climate change and/or other
environmental changes.

6. Volcano Trends
•Around 50–70 volcanoes
erupt every year.
•There is no trend, upward or
downward, in eruption
frequency.
•Very large magnitude
eruptions (e.g. Mt Pinatubo in
1991) are rare.
•Notice that 8 of the top 10
eruptions have occurred since
1990.
Country Year
Number of
people
affected
Philippines
(Mt Pinatubo) 1991 1,036,065
Nicaragua 1992 300,075
Ecuador 2006 300,013
Indonesia 1982 300,000
Indonesia 1969 250,000
Comoros 2005 245,000
Philippines 1993 165,009
Papua New Guinea 1994 152,002
Ecuador 2002 128,150
Dem. Rep. Congo 2002 110,400
Top ten volcanic eruptions since
1900 by number of people affected

7. Edexcel AS Geography Unit 1
World at risk: Global hazard trends

8. Hurricane Trends
•Trendsinhurricanes,especiallyintheAtlantic,are
acontroversialmatter.
•Someresearchershavelinkedincreasedhurricane
activitytoglobalwarming.
•Othersarguethatthereisanaturalcycleinthe
AtlanticcalledtheAtlanticMultidecadalOscillation
(AMO)whichexplainsthehighnumberofmajor
hurricanesinthe1940sand1950s,andmore
recently.
•Despitevariationsinmajorhurricanefrequency,
thereisalong-termtrendintheUSAoffalling
hurricane-relateddeathsbutrisingeconomiccosts.

9. Hurricane trends
•Onecertaintrendistheriseinthenumberofpeoplelivingon
theUScoast.
•InFloridaandtheGulfCoast,somecoastalareashaveseen
populationsriseby400%since1980.
•Thismeansincreasingnumbersofpeopleareatriskfrom
hurricanes.
•Althoughawarenessofhurricanes,education,warningand
evacuationsystemshaveallimprovedintheUSA,the
potentialforeconomiclosscontinuestogrowascoastal
populationsrise.
•Thefullimpactofrisingpopulationswasfeltin2005,when
theFloridaandGulfCoastswerestruckbyfivemajor
hurricanes(Dennis,Emily,Wilma,Rita,Katrina),causingan
estimatedUS$120billionindamageandthelossof2,200
lives.

10. Global Warming
Global temperatures, 1850–2008
(IPCC –Intergovernmental Panel on Climate Change)

11. Global Warming
•Manyscientistsbelievethatincreasedglobalwarmingwill
leadtomoreunpredictableweatherandariseinextreme
weatherevents.
•Globaltemperatureshaverisensince1910,andata
consistentlyrapidratesincethelate1970s.
•Thefactthatthereareonlyfewyearsofreliabledataabout
globaltemperaturesmakesthescientists’taskofaccurately
predictingfuturechangesmoredifficult.
•Somedata,suchasthe20cmriseinglobalsealevelsince
1900andthedeclineinArcticseaicesincethe1970s,are
morereliable.
•Thereisgrowingsuspicionthatrisingtrendsindroughtand
floodeventsmayheraldtheeffectsofglobalwarmingto
come.

12. Flood Disaster Trends
Reported global flood disasters and death tolls, 1977–2007

13. Flood Disaster Trends
•Trends in global flood disasters show significant rises since the
early 1990s.
•This could be an early signal of climate change.
•It may also be related to rising populations, rapid
urbanisation, deforestation and other land-use changes.

14. El Niño/La Niña
•Aswellasglobalwarming,theEl-Niño/La-Niñacycleisknown
tohaveclimaticconsequencesonaglobalscale.
•ChangesinPacificOceancirculationhaveknock-onweather
effectsinotherpartsoftheworld.
•HazardsassociatedwithEl-Niñoarewellknown,suchas
droughtinIndonesiaandfloodinginPeru.
•El-Niño/La-Niñacycles,whichareunpredictable,addyet
anotherlayerofcomplexitytothecalculationofhazardrisk.

15. Human Trends
•Sometrendsamongthehumanpopulationaddtoincreasing
risk.
•Oneoftheseisurbanisation.Over50%oftheworld’s
populationnowlivesinurbanareas,comparedto29%in
1950.
•Thesecrowdedspacesareespeciallyvulnerabletomajor
earthquakes,floodsandhurricanes.
•Worldpovertycontinuestobeamajorissue,reducingthe
capacitytocopewith,andincreasingthevulnerabilityto
hazards.
•Althoughtheglobalproportionofpeoplelivingonlessthan$1
perdayisfalling,totalnumbersrosefrom36millionto50
millioninLatinAmerica,and164to314millioninAfrica
between1981and2001.

16. Human trends
•Pressureonlandfromgrowingpopulationsleadsto
deforestationandconversiontofarmland.
•Deforestationcansignificantlyincreasehazardrisk.
•Theriskoflandslideisgreateronslopeswhentrees
areremoved.
•Withnovegetationtointerceptrain,flash-floodrisk
rises.
•UrbanDisastersareinincreasingtrendasurban
populationisincreasing

17. Global Trends
Disasters related to human development levels
Overall, global trends show that the numbers of reported disasters and
people affected are rising, but the number of people killed by disasters is
falling.

18. Disaster Management
•Deathtollsarereducedwhenpopulationsarepreparedforapossible
hazard.
•Somehazardscanbepredicted,e.g.floods,hurricanes,droughtand
volcaniceruptions.
•Predictionallowsforwarning,and,whenpossible,evacuation.This
cansavelives,butisunlikelytoreduceeconomiclosses.
•Afteradisaster,immediaterescueandreliefisessential.
•‘Rapidresponse’hasimprovedconsiderablyoverthelastfew
decades.Internationalreliefeffortsnowoccurquicklyinresponseto
disasters.
•Thissaveslivesbutthenumbersaffectedandtheeconomiclosses
arestillhigh.
The challenge is to ‘disaster proof’ communities using appropriate
building techniques, land-use zoning, education and developing
prevention technology. These responses are longer term, costly
and beyond the reach of many in the developing world.