Geoscience Reference
In-Depth Information
a. given. climate. variable). will. generally. increase. under. continued. climate. change,.
it.is.not.clear.for.most.aspects.of.climate.(e.g.,.wind.speed,.temperature,.frequency.
of. drought). what. the. magnitude. of. departure. or. the. spatial. pattern. in. such. devia-
tions.will.be..Additionally,.for.both.hindcasts.and.forecasts,.much.higher.levels.of.
uncertainty.accompany.predictions.of.precipitation.than.predictions.of.temperature.
(Hulme.2005;.IPCC.2007)..Also,.much.remains.to.be.learned.of.how.climatic.vari-
ables.(even.ones.as.fundamental.as.temperature).vary.in.both.their.status.and.trends.
at. multiple. scales. (Pepin. and. Lundquist. 2008),. how. any. trends. will. interact. with.
trends.in.other.climatic.parameters,.and.how.these.dynamics.will.affect.ecological.
systems..Importantly.for.managers.of.individual.land-management.units,.modelers.
are.still.currently.struggling.with.statistical.and.dynamical.downscaling.of.regional-
climate. models. that. will. produce. climate. forecasts. at. (iner). resolutions. that. are.
meaningful.to.manageable.portions.of.those.units.and.to.biological.entities.within.
the.units.(McLennan
this volume
).
Correspondingly,.ecological.uncertainties.in.response.to.climate.are.compounded.
by. these. uncertainties. in. predicting. climate. itself.. For. example,. for. many. taxa,. it.
remains.unknown.how.species.(e.g.,.with.different.life-history.characteristics,.such.as.
r
.vs..
K
selection).will.respond.to.more.frequent.extreme-weather.events.(McLennan
this volume
;.Wilson.and.Gutiérrez
this volume
);.it.is.even.less.well.known.how.such.
altered. frequencies. will. affect. species. interactions. and. ecological. processes.. Past.
research.shows.that.at.least.for.populations.living.in.topographically.heterogeneous.
systems,.responses.to.weather.are.mediated.by.the.topography.of.the.habitat.patch.
(Singer.1972;.Singer.and.Ehrlich.1979;.Weiss.et.al..1987;.1988;.Murphy.and.Weiss.
1988).. To. illustrate. the. complexity. of. alterations. to. multiple. climate. factors,. there.
are.many.possible.ways.in.which.species.may.respond.to.not.only.altered.precipita-
tion.regimes,.but.also.to.the.interaction.of.altered.precipitation.and.temperature..For.
example,.although.some.areas.of.Alaska.are.predicted.to.receive.increased.amounts.
of. precipitation. in. the. coming. decades,. the. rate. of. potential. evapotranspiration.
(or.water.stress).at.those.areas.may.actually.increase,.if.rising.temperatures.effec-
tively.outstrip.the.higher.precipitation.(O'Brien.et.al..in.preparation)..As.evidenced.
throughout.the.topic,.nearly.all.climate-biota.interactions.will.be.more.fully.under-
stood.with.better.understanding.of.the.spatial.and.temporal.scales.of.climate.(and.
other.stressors).that.are.important.for.various.ecosystem.components.and.processes..
Temporally,.for.example,.the.time.lags.after.which.climatic.inluence.will.be.exhib-
ited.in.species.can.vary.across.taxa.and.years,.but.are.generally.unknown.(Hallett.et.
al..2004;.Thomas.et.al..2004;.Cole.2010)..In.low-productivity,.event-driven.systems.
such.as.the.Grand.Canyon,.however,.Cole.(2010),.using.paleo-reconstruction.of.81.
assemblages,.found.that.multiple.centuries.were.required.for.plant.communities.to.
re-establish.and.stabilize.after.periods.of.climate.warming.in.the.early.Holocene.
The.understanding.of.more-complex.dynamics.that.is.beginning.to.emerge.from.
research.and.monitoring.suggests.a.further.suite.of.questions..For.example,.as.of.now.
we.only.know.particular.case.examples.of.how.synergies.of.climate.with.other.eco-
system.drivers,.disturbances,.and.stressors.(both.natural.and.anthropogenic).affect.
biotic. response.. Furthermore,. although. it. has. been. modeled. for. some. ecosystems.
(e.g.,.Luo.et.al..2008),.it.is.largely.unknown.how.historically.unprecedented.levels.
of.atmospheric.CO
2
.around.the.globe.(IPCC.2007).will.affect.species'.physiology.
