Geoscience Reference
In-Depth Information
•.
Ramp. disturbances. (Lake. 2000). are. long-term. events. whose. intensity.
changes.over.time..Potentially,.these.are.of.great.importance,.especially.if.
they. incorporate. positive. feedback. loops. that. cause. accelerating. ecologi-
cal.effects..For.example,.the.combination.of.steadily.rising.sea.levels.and.
storminess.have.the.potential.to.erode.dunes.and.destroy.stabilizing.vegeta-
tion,.thus.enabling.further.erosion.to.occur.
•.
Interactions.among.disturbances.may.combine.with.each.other.or.with.con-
taminants.(Schiedek.et.al..2007).to.produce.greater.effects.than.each.distur-
bance.alone..For.example,.storms,.raised.sea.levels,.and.reduced.sediment.
supply.will.act.in.concert.to.exacerbate.beach.erosion..Apart.from.the.loss.
of.beach.habitat,.these.factors.may.combine.to.negatively.affect.the.nesting.
of. turtles. (Poloczanska. et. al.. 2009).. In. addition,. calcifying. species. with.
acid-weakened.shells.may.be.especially.vulnerable.to.the.physical.effects.of.
increased.storminess.and.vehicular.trafic..Also,.coastal.aquifer.depletion.
may.cause.land.subsidence.that.interacts.with.climate.change.to.magnify.
the.effects.of.sea-level.rise.(Galbraith.et.al..2002)..These.interactive.distur-
bances.are.more.dificult.to.assess.scientiically.than.single.factors,.and.are.
therefore.poorly.understood.and.probably.underrated.as.risks.
Managing. these. disturbances. requires. the. assessment. of. risk. and. vulnerability..
Risk.is.a.function.of.the.probability.of.an.adverse.event.and.its.consequences;.vulner-
ability.is.a.function.of.exposure.to.pressure(s),.sensitivity.to.change,.and.the.capacity.
to.adapt.(IPCC.1992)..The.vulnerability.of.the.beach.habitat.is.largely.dependent.on.
the.rates.of.sea-level.rise,.coastal.erosion,.and.frequency.of.extreme.events.(Voice.et.al..
2006)..Reduced.sediment.supply.from.impounded.rivers.is.also.a.factor..On.this.basis,.
together.with.the.biological.effects.of.climate.stresses.and.the.dependencies.on.vul-
nerable.adjacent.systems,.beaches.are.clearly.“especially.vulnerable”.(CSIRO.2002)..
Indeed,.dunes.and.beachfronts.were.included.among.the.“vital.areas”.that.would.be.
lost.or.experience.dysfunction.via.multiorder.effects.(Cocks.and.Crossland.1991).
The.greatest.threats.will.apply.to.urban.sandy.beaches.because,.unlike.nonurban.
beaches,.it.is.unlikely.that.they.will.be.allowed.to.retreat.at.the.expense.of.societal.
assets..If.these.assets.are.to.be.protected.by.seawalls,.the.very.existence.of.beaches.
will.be.jeopardized.as.seas.rise.(Cowell.et.al..2006)..Thus,.the.coastal.squeeze.will.
tighten.as.stresses.due.to.climate.and.human.population.grow.further.
Although.the.exposure.of.all.ecosystems.to.climate.change.is.clear,.knowledge.of.
the.ecological.effects.is.an.undeveloped.but.rapidly.evolving.ield.
ECOLOGICAL EFFECTS OF CLIMATE CHANGE
Predictions.about.overall.ecological.effects.are.necessarily.imprecise.because.several.
forcing. factors. (i.e.,. sea. level,. storminess,. wave. climate,. water. temperature,. water.
chemistry,.and.physical.beach.processes).are.involved,.they.may.interact.in.complex.
ways,. and. some. effects. may. be. indirect.. Moreover,. there. is. uncertainty. about. the.
magnitude.of.change.in.these.factors,.prompting.various.physicochemical.scenarios.
(IPCC. 2007;. Brown. and. McLachlan. 2002;. CSIRO. 2002;. International. Scientiic.
Steering.Committee.2005;.Cowell.et.al..2006)..Nonetheless,.there.is.little.doubt.that.
