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ES8007 Climate and Climate ChangeES1007 Oceans, Atmosphere and Climate
© NEA-MSS
Humans and Climate-Part II
Asst. Prof. WANG
Xianfeng
Asian School of theEnvironment
Nanyang Technological
University5 April, 2016
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www.earthobservatory.sg
ES8007 Climate and Climate ChangeES1007 Oceans, Atmosphere and Climate
© NEA-MSS
Humans and Climate-Part I
Asst. Prof. WANG
Xianfeng
Asian School of theEnvironment
Nanyang Technological
University5 April, 2016
8/18/2019 8.Humans and Climate
3/24
www.earthobservatory.sg
All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
KEY QUESTIONS
How did climate afect hma!evoltio!"
How cold ice volme #sea level$cha!ge afect hma! migratio!"
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
HU%&N E'O(UTION T)EE
(Ruddiman, 2014, Earth’s Climate: Past and Future)
1. Humans originated and evolved in East Africa.
2. The last ~5 million years span the evolutionaryline from primitive apes (particularlychimpanzees to the australopithecines (!southern apes"# ~$%& million years ago to our
o'n genus# Homo (~2 million years ago# andfinally our o'n species# Homo sapiens(!intelligent man"# !anatomically modernhumans"# ~2# years ago.
). *ipedalism (+eing a+le to 'al, upright on t'olegs# an energy%saving mechanism for travelinglong distance- 'as pro+a+ly developed ~$%&million years ago# and has +een considered asthe defining characteristic that separated thehominins from the hominoids (humanli,e apes#pro+a+ly the single most important event inhuman evolution.
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
(Stanley, 2009, Earth System History; Ruddiman, 2014, Earth’s Climate: Past and Future)
1. harles /ar'in 'as among the first to suggest a lin, +et'een the African arid savanna andhuman evolution.
2. The uplift and su+sidence of the East African 0ift resulted in a comple topography that+loc,ed the effective moisture from transferring inland from the ndian 3cean# hence causedintensified aridification and ever%epanding savanna in Africa# and then stimulated human
evolution +y +ipedalism developing.
&*)I+&N TO,O-)&,HY
The East African 0ift4
All of the early () 6ahominin fossil sites arelocated along the narro'
+elt of the East African 0ift.
Hominin footprints# 7aetoli#
Tanzania# ~).& 6a.
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
)O(E O* +(I%&TES&'&NN& HY,OTHESIS
This hypothesis ties human evolutionto long%term drying in Africa andglo+al climate processes.
Through the last 5 million years# 'hileplanet is cooling# Africa is getting
dryer and less forested. The tropicalrainforests in Africa largely have+ecome semi%arid grasslandsavannas.
This 'ould force hominins to adapt
from forests to an open environment#and force them to move rapidly tocover longer distances to survive.
auses of drying may +e many4tectonic uplift# ice volume# lo'er 32#
and monsoons.(Ruddiman, 2014, Earth’s Climate: Past and Future)
+/ vs +0
1la!ts
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
HU%&N %I-)&TION OUT O* &*)I+&
Hominin spreading
1. Homo sapiens
2. Neanderthals
3. Homo erectus
?
8or most of the last ) million years# hominins onlydeveloped slightly +eyond the most primitive level of9tone Age of life4 e.g.# control of fire and gradually moresophisticated stone tools.
Ho'ever# 'hen our species appeared# the pace of change+ecame faster. The early human !culture" 'as developed4
cave paintings# figure statues# shell :e'elry# etc.(Stanley, 2009, Earth System
?
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
I+E +O)E )E+O)2
(Petit et al., 1999, Nature3arm tem1.4 low ice volme4 high sea level5 cold tem1.4 low sea level
~1!
~"#
~1$%1
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
%ONSOON&( +I)+U(&TIONS
(Ruddiman, 2014, Earth’s Climate: Past and Future)
Seasonal monsoon circulations
n summer# more rapid heating of landsurfaces than of the ocean producesrising motion over the continents anddra' moist air in from the ocean#producing precipitation over the land.
n 'inter# more rapid cooling of the landsurface than of the ocean producessin,ing motion over the continents andsheds cold dry air out over the 'armocean# shifting most 'inter precipitationout to sea.
A similar pattern can +e found on longertimescales. ;enerally spea,ing#summer monsoon is strong ininterglacial periods# +ut 'ea, in glacialperiods.
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
6NO)TH 'S. SOUTH 2IS,E)S&( %O2E(7
1
1
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
,EO,(IN- O* NO)TH &%E)I+&
(Stanley, 2009, Earth System
The megafaunalpopulation 'ashighly diverse untilthe late stages ofthe most recentdeglaciation in@orth America. *utmost of the largemammal species+ecame etinct'ithin a short timeperiod centered on
~12#5 years ago.
/id climate cause the megafaunal
etinction directly=
9harp spear pointsand over,ill hypothesis
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
2&3N O* +I'I(I8&TION
3ur invention of agriculture coincides 'iththe onset of the sta+le climate of the past~1# years.
This is ~1# years of climatic
sta+ility that ena+led humanity toevolve and cultures to develop.
Agricultural revolution in the moist andfertile land4 several ,inds of agriculture
originated in the 8ertile rescent regionnorth and east of the 6editerranean# andgradually spread into Europe# @orth Africa# and other parts of Asia.
(Alley, 2007; Ruddiman, 2014, Earth’s Climate: Past and Future)
Holocene# the current interglacial period#is characterized +y a 'arm and relativelysta+le climate. A strong monsoon prevailsin the +road regions of Africa and Asia.
The region also sa' the developmentand flourishing of the earliest human
civilizations.
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
KEY QUESTIONS
How may climate cha!ge afect the9ates o9 +hi!ese a!cie!t dy!asties"
Is a glaciatio! overde" +old earlycivili:atio!s already have alteredclimate"
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
t/s tal0 a,ot a 2ro3y for rainfall
)emember that !ot all water #H;O$ is the same. Some H
;O is
heavier tha! other H;O 1roto!s a!d >!etro!s i! its !cles
?t a small @ #abot A.;@$ has> 1roto!s a!d BA !etro!s
That heavier H;B>O does!Ct eva1orate as easily as thelighter H;
BDO. So rai!water is actally lighter tha! the
seawater 9rom which it comes.Similarly4 the rst water to 9all ot o9 the clod has a
larger @ o9 heavier o=yge! tha! water that 9alls ot later.
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
+&'E 2E,OSITS #ST&(&-%ITES &N2ST&(&+TITES$ &S & +(I%&TE &)+HI'E
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
INTO THE 2&)K TO SHE2 SO%E(I-HTS ON )E+ENT +(I%&TE
%i!eralFlade! rai!water 1asses
throgh soil a!d rocG cracGs4 a!ddri1s o!to the cave oor. The waterthe! eva1orates. +alcite #+a+O/$ is
the mi!eral le9t behi!d. It 9ormsstalagmites that rise 9rom the oor o9
the cave.
htt1wiGi1ediacommo!s(echgillaJ+aveJ,earlsia!J-l9.1g
+ave de1osits #stalagmites a!d
stalactites$ ca! be a very se9lclimate archive. &!d 1ast climatecha!ge ca! be recorded throgh thecha!ges o! the ratio o9 B>OBDO i! thecalcim carbo!ates.O!e o9 the sig!ica!t adva!tages tose stalagmite to reco!strct 1ast
climate is that they ca! be dated1recisely by si!g the radioactivedecay o9 ra!im #here ;/0U$ tothorim #here ;/A Th$ i! thecarbo!ates. The less ra!im a!d the
more thorim4 the older the sam1le.
-eochemists at EOS&SE se a masss1ectrometer to measre the atoms
o9 ra!im a!d thorim4 a!d the!
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
+&'E 2E,OSITS #ST&(&-%ITES &N2ST&(&+TITES$ &S & +(I%&TE &)+HI'E
9o# the ratio of 13 to1&3 is a climate proy#
and can record the
'ea,ening and
strengthening of theEast Asian monsoon.
7etBs loo, at a cave at
8/18/2019 8.Humans and Climate
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e a v i e r H
; O
( i g h t e r
H ;
O
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The Ha!g+hao U1risi!go9 the >LAs a!d>>As was 9eledby a droght4whe! locstsswarmed thela!d4 a!d led to
the e!d o9 the Ta!g 2y!asty.
2ri!g the Norther! So!gStro!g %o!soo! ,eriod4 the+hi!ese 1o1latio! more
tha! tri1led. )ice becamethe sta1le o9 the +hi!ese
Ha!g+hao
)iver sce!e at Qi!gmi!g 9estival
8h Ya!:ha!g4
Bst %i!gem1eror
&t the e!d o9 the Ya!2y!asty4 there were a serieso9 droghts a!d a 1easa!t1risi!g. I! B/D>4 8h
Ya!:ha!g4 the leader o9 the
1risi!g4 tooG ?eii!g. His1are!ts a!d older brother all
The +ho!g:he!2roght4 at the e!d o9the %i!g 2y!asty#BD/LFBD0/$4 is G!ow!as o!e o9 the most
severe i! +hi!esehistory. It afectedmore tha! ;A 1rovi!cesi! N a!d S +hi!a. The1rolo!ged droghthel1ed (i 8iche!gorga!i:e a 1o1lar1risi!g a!d overthrow+ho!g:he! i! BD00.
(i 8iche!g
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
+(I%&TE &N2 +I'I(I8&TION
500
51 15Cear (A/
multiyear droughtsi!s o9 a 'iGi!g bar! i! -ree!la!d
9everal ma:or civilization collapses coincide 'ithperiods of intense droughts# or etremely cold climate.
Abandoned in ~14
th
and 15th centuries
Dariations in climate can +e dangerous to societies and civilizations. 3ther
factors can also play a role4 political sta+ility ('ar# overeploitation of soiland resources# food and 'ater securities
Maya, ucatan
(Zhang et al. 2008, Science)
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
2I2 E&)(Y *&)%E)S &(TE) +(I%&TE"
Eventually# the relationship +et'een humans and their environment
+egan to change. nstead of +eing passive players# human +egan toactively influence their environment and EarthBs climate.
*y clearing of forests# slashing and +urning agriculture# and other practices# evenfarmers 'ith 'ooden plo's could alter the atmosphere. The modern man,ind 'illfurther mess up the planetBs thermostat. %%%
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
IS & -(&+I&TION O'E)2UE"
(Kump, Kasting and Crane, 2010, The Earth System; Petit et al., 1999, Nature)
!emperature stability
in last 1",""" years
B. & sawtooth 9eatre o9 the glacialFi!terglacial cycle the tra!sitio!9rom glacial 1eriods to i!terglacial 1eriods is characteri:ed by a!abr1t warmi!g4 a!d the! relatively4 it cools gradally i!toglacials.;. I!terglacial co!ditio!s o!ly 1revailed abot BA@ o9 the,leistoce!e glaciatio!. However4 the climate i! the 1ast MBA4AAA
years is !sally commo!. It a11ears to be the lo!gest stableclimate i! the 1ast 0AA4AAA years.
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
E&)(Y &NTH)O,O-ENI+ HY,OTHESIS
(Ruddiman, 2014, Earth’s Climate: Past and
1. “Wrong-way trend”: during the current
interglaciation (Holocene), greenhouse-gas
(here, CH4) concentration did not track the
.H. su!!er insolation change, "ut instead
started to rise at #$,%%% years ago.
&. 'ast $ interglacial CH4 records ro! ntarctic ice
cores. CH4 concentration rose during the later *art o
Holocene, "ut continuously ell during *re+ious
interglaciations.
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All objects emit radiation as long as they have a non-zero temperature on the kelvin
(K) scale. x °C = (273.15 + x) K
E&)(Y &NTH)O,O-ENI+ HY,OTHESIS
(R ddi 2014 E h’ Cli P d
1. ice was irst culti+ated in China. y 4,%%%
years ago, archeological sites (red) show that
rice irrigation was *resent across !ost o
China, where rice is !ainly grown in its south
today ("lue).
&. ince $,%%% years ago, rice irrigation has
e/*anded ra*idly into other countries inoutheast sia and 0ast sia
. e+eral hu!an
acti+ities can generate
CH4, including irrigatingields, "urning "io!ass
(weeds and cro*
residues), tending
li+estock, and *roduction
o organic wastes.
0arly rice ar!ing
and ano!alous
!ethane (CH4) trend