tipping points related to climate...

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