Uncertainty, Lags, and Nonlinearity: Challenges to Governance in a Turbulent World Thomas Homer-Dixon CIGI Chair of Global Systems Balsillie School of International Affairs Waterloo,Canada May

UNCERTAINTYLAGSNONLINEARITYOPENNESS

UNCERTAINTYLAGSNONLINEARITYOPENNESS

UNCERTAINTYLAGSNONLINEARITYOPENNESS

We need to shift from seeing the world as composed mainly of MACHINES to seeing it as composed mainly of COMPLEX SYSTEMS

Whereas MACHINES can be taken apart, analyzed, and fully understood (they are no more than the sum of their parts)can be taken apart, analyzed, and fully understood (they are no more than the sum of their parts) exhibit “normal” or equilibrium patterns of behaviorexhibit “normal” or equilibrium patterns of behavior show proportionality of cause and effect, andshow proportionality of cause and effect, and can be managed because their behavior predictable...can be managed because their behavior predictable...

COMPLEX SYTEMS are more than the sum of their parts (they have emergent properties)are more than the sum of their parts (they have emergent properties) can flip from one pattern of behavior to another (they have multiple equilibriums)can flip from one pattern of behavior to another (they have multiple equilibriums) show disproportionality of cause and effect (their behavior is often nonlinear, because of feedbacks and synergies), andshow disproportionality of cause and effect (their behavior is often nonlinear, because of feedbacks and synergies), and cannot be easily managed because their behavior is often unpredictable.cannot be easily managed because their behavior is often unpredictable.

We’re moving from a world of RISK to a world of UNCERTAINTY (unknown unknowns)

So, we must move from “management” to Complex Adaptation

Battisti and Naylor, “Historical warnings of future food insecurity with unprecedented seasonal heat.” Science (9 January 2009):

Battisti and Naylor, “Historical warnings of future food insecurity with unprecedented seasonal heat.” Science (9 January 2009):

IPCC 2007

UNCERTAINTYLAGSNONLINEARITYOPENNESS

LAGS Between emission and climate responseBetween emission and climate response Between cuts to emissions and reduction of warmingBetween cuts to emissions and reduction of warming Between policy decision to change energy infrastructure and completion of this changeBetween policy decision to change energy infrastructure and completion of this change

“ [We show] that to hold climate constant at a given global temperature requires near zero future carbon emissions.... As a consequence, any future anthropogenic emissions will commit the climate system to warming that is essentially irreversible on centennial timescales.” Matthews, H. D., and K. Caldeira (2008), “Stabilizing climate requires near-zero emissions,” Geophys. Res. Lett.

“ “[The] climate change that takes place due to increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop. Following cessation of emissions, removal of atmospheric carbon dioxide decreases radiative forcing, but is largely compensated by slower loss of heat to the ocean, so that atmospheric temperatures do not drop significantly for at least 1,000 years. Among illustrative irreversible impacts that should be expected if atmospheric carbon dioxide concentrations increase from current levels near 385 parts per million by volume (ppmv) to a peak of 450–600 ppmv over the coming century are dry-season rainfall reductions in several regions comparable to those of the ‘‘dust bowl’’ era and inexorable sea level rise.” Solomon et al, “Irreversible climate change due to carbon dioxide emissions,” Solomon et al, “Irreversible climate change due to carbon dioxide emissions,” PNAS (February ).

Hansen, Atmos. Chem. Phys. 7 (2007):

UNCERTAINTYLAGSNONLINEARITYOPENNESS

Years before Present Ice Accumulation Rate (meters per year)

More rapid warming at poles One reason: Ice-albedo feedback Atmospheric warming Lower reflectivity of ocean surface Melting of ice Increased ocean absorption of sun’s energy radiative positive feedback, fast

mK 2

Jakobshavn Ice Stream in Greenland Discharge from major Greenland ice streams is accelerating markedly. Source: Prof. Konrad Steffen, Univ. of Colorado

Atmospheric warming Rotting and burning of organic matter Death of forests Release of CO 2 carbon cycle positive feedback, potentially fast

Atmospheric warming Increased airborne fraction Decreased efficiency of carbon sinks carbon cycle positive feedback, slow

Up to 30 percent decrease in the efficiency of the Southern Ocean sink over the last 20 years Strengthening of the winds around Antarctica increases exposure of carbon-rich deep waters Strengthening of the winds due to global warming and the ozone hole Declining efficiency of the ocean sink Le Quéré et al. 2007, Science

Atmospheric warming Rotting of organic matter Melting of permafrost Release of CH 4 and CO 2 carbon cycle positive feedback, potentially fast