tipping points related to climate...
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Tipping points related to climate change
Tim Lenton, Marten Scheffer, Tim Kohler, Chi Xu, Jens-Christian Svenning, Egbert van Nes
Tipping points
Meincke etal. (2003)MarineScienceFrontiers
ThermohalinecirculationoftheoceanNorthAtlanticDeepwater(NADW)formation
Genericexample
Janssenetal. (2003)CurrentAnthropology 44:722-8
Sunk-costeffectsandsocietalcollapse
Tipping pointearly warning
Early warning indicator
Thanks to Chris Boulton for the animation
0100,000200,000300,000400,000500,000600,000Age (yr BP)
300
500
400
600
180200
220240260
280
Today’s CO2 Concentration
CO
2[p
pmv]
Temperature proxy
0100,000200,000300,000400,000500,000600,000Age (yr BP)
300
500
400
600
180200
220240260
280
Temperature proxy
After 40 More Years of current energy use patterns
CO
2[p
pmv]
Today’s CO2 Concentration
Coupling between climate tipping points
Age (thousands of years ago = ka)
Time
Temperature
inGreenland
MonsooninIndia
Mon
soon
in
Amazon
Deplazes et al. (2013) Nature Geoscience 6: 213-217
Holocene abrupt changes in the hydrological cycle
Collapse of Neolithic Culture of China
Time
Wang et al. (2013) Chinese Geographical Science 23: 1-12
Holocene climate variability was cyclic
Donge Cave(China)d18Oproxyformonsoonstrength
~210yr DeVries cycleTotalsolarirradiance
Waveletcoherenceofthetworecords(rightwardarrowindicatesinphase)
Steinhilber et al. (2012) PNAS 109: 5967-71
~1000yr Eddycycle
Holocene climate variability was cyclic
Deke Xu et al. (2014) Scientific Reports 4: 3611
Totalsolarirradiance
EastAsianlakerecord
Greenlandtemperature
The apparent human climate niche
Xu,Kohler,Lenton,Svenning,Scheffer(submitted)
500BPbasedonHYDEdatabase6Kyr BPbasedonArchaeoGlobe
Temperature experienced by humans
Xu,Kohler,Lenton,Svenning,Scheffer(submitted)
HY=HYDEAG=ArchaeoGlobe
Civilizations emerged at the edge of the niche Locationsof(thecapitalsof)ancientcivilizations
Xu,Scheffer,Kohler,Lenton(inprogress)
Were ancient civilizations cyclic?
Civ
ilizat
ion
Emer
genc
e
LukeKemp’sdatacompilation
Scheffer,Kohler,Lenton,Xu,vanNes(inprogress)
~210
yr
~500
yr
Were cycles in climate and civilization linked?
Scheffer,Kohler,Lenton,Xu,vanNes(inprogress)
Data of Bocinsky et al. (2016) Science Advances 2: e1501532
Did climate change collapse senescent societies?
Scheffer,Kohler,Lenton,Xu,vanNes(inprogress)
Earlywarningsignalsbefore4collapsesinBocinsky etal.(2016)data
Summary• Both climate and civilizations are complex systems with multiple positive and
negative feedback loops and potential tipping points
• The Holocene was relatively stable but there were cyclic variations in temperature and tipping points in the hydrological cycle
• Humans live in a very conserved ‘apparent climate niche’ and civilizations rose and fell predominantly on the dry side of that niche
• Rises and falls in past civilizations appear cyclic and linked to climate cycles
• The human climate niche is set to move dramatically this century in a world passing climate tipping points – the existential threat to civilization is obvious
Geographical position of the apparent human temperature niche
Xu,Kohler,Lenton,Svenning,Scheffer(submitted)
Were ancient civilizations cyclic?
Scheffer,Xu,vanNes,Kohler,Lenton(inprogress)
Civ
ilisat
ion
Emer
genc
e
Emergencetime Collapsetime Duration