Overview of the biology of extreme events Vincent P Gutschick Global Change Consulting Consortium Las Cruces, NM [email protected]@gmail.com)

Overview of the biology of extreme events

Vincent P Gutschick Global Change Consulting Consortium

Las Cruces, [email protected])

Hormoz BassiriRadBiological Sciences, University of Illinois

Chicago, IL [email protected]

2008 Fall MeetingAmerican Geophysical Union

San Francisco, CA15-19 December 2008

PowerPoints available at:http://gcconsortium.com/agu08.ppt

and ../agu08long.ppt

Extreme events are…

1) … rare, and impactful … attention-getting

2003 heat wave in Europe

- for humans

- for atmospheric fluxes

Hurricane Katrina

Conifer dieoff across Western North America

Rise of atmospheric CO2

Snowball Earth

…and many more

….appearing (but not really) categorically different from

(more) normal events extremity is a distribution

KH Raffa et al., BioScience 58(2008): 501-517

Extreme events are…

1) … rare, and impactful … attention-getting

2) Inordinately weighted in the physiology, ecology, and

evolution of organisms

Hence, also, in biogeochemical cycles

Katrina: 0.1 Pg C reinjection expected from tree death

Conifer dieoff: 0.3 Pg C reinjection

2003 heat wave in Europe (-NPP, -Rd, -WUE, -APAR; drought)

Snowball Earth: end of CH4 atmosphere, major greenhouse

Yet, mostly anecdotal to date – no comprehensive framework

Extreme events are…

1) … rare, and impactful … attention-getting

2) Inordinately weighted in the physiology, ecology, and

evolution of organisms

3) Of diverse origins:

● meteorological – heat wave, hurricane

● biotic

- evolutionary – Snowball Earth

- anthropogenic

– land-use change; deforestation ΔT, ΔP (incl. monsoons)

- introduction of exotics (chestnut blight,

Dutch elm, Oz rabbits…)

● orbital – ice ages

● tectonic- Toba eruption, 70 kya

GF Gravatt, Unasylva 3(1949):3-7)

Extreme events are…

1) … rare, and impactful … attention-getting

2) Inordinately weighted in the physiology, ecology, and

evolution of organisms

3) Of diverse origins: meteorological, biotic, orbital, tectonic

4) Occurring/recurrent, over wide scales

- of time

Mega-years: Snowball Earth, C4 plant evolution

Years: Darwin's finches, evolution of beak size

Hours or days: flower drop in extreme T events

- of space (same examples)

Grant PR (1986) Ecology and evolution of Darwin’s finches.

Princeton University Press

Extreme events are… …….

5) For biological EEs…and for much of consequent effects on

climate, hydrology, etc.:

A) Defined by organismal effects, not drivers

Chihuahuan desert: heat, drought effects native vs. introduced

B) Physiological in effect – Leaf damage from heat, frost, cold+light

And/or ecological – Cheatgrass and fire regime; pollinator timing

And/or evolutionary

Toba eruption signature on human genome

20th-year extreme drought: Ci/Ca selected in Encelia farinosa;

Pinecone scale size selection in abundant years

Microsites soil water availability glycolytic enzyme in pinyon pine

MC Ball et al. (2002)

Extreme events are…

…….

5) For biological EEs…and for much of consequent effects on

climate, hydrology, etc.:

A) Defined organismally

B) Physiological, ecological, evolutionary

C) Likely more important than mean values of conditions

Recent manipulative experiments

Natural conditions: frosts structuring ecosystems

Fitness effects likely concentrated in EEs

D) Likely: fitness effects concentrated in the recovery phase

Drought recovery: resource acquisition restarts in recovery, not event

Recovery can be protracted, even for native species

A Jentsch et al., Front Ecol Environ 2007; 5(7): 365–374

Courtesy of D.Sims

Extreme events are…

1) … rare, and impactful … attention-getting

2) Inordinately weighted in the physiology, ecology, and

evolution of organisms

3) Of diverse origins: meteorological, biotic, orbital, tectonic

4) Occurring/recurrent, over wide scales of time and space

5) For biological EEs: A) Defined organismally; B) Physiological,

ecological, evolutionary; C) More important than “normal”

conditions; D) Often more evident in recovery phase

6) Positive as well as negative: e.g., pluvial events for forest

reestablishment after fire

PM Brown & R Wu, Ecology 86(2005): 3030-3038

Extreme events are…

……

6) Positive as well as negative: e.g., pluvial events for forest

reestablishment after fire

7) Generally defined by sequences, not points in time;

Order and rate of driver events matters

High T's in spring vs. winter;

Cold-weather leaf drop in Larrea tridentata of warm deserts

High-T flower drop in Opuntia cacti in spring (see earlier slide)

Hardening to low T in Eucalyptus pauciflora

B) Thus, they are defined as events, not trends

Trends increase/ decrease probability of pointwise extremes in

driving variables, such as T

Example: Eucalyptus pauciflora in pastures

Time scales important – rise of CO2: trend event in evolutionary timehttp://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_TS.pdf

Aust. J. Plant Physiol. 25(1998): 27-37

VP Gutschick & H BassiriRadNew Phytol. (2003) 160: 21–42

Extreme events are…

……

5) For biological EEs: A) Defined organismally; B) Physiological,

ecological, evolutionary; C) More important than “normal”

conditions; D) Often more evident in recovery phase

6) Positive as well as negative: e.g., pluvial events for forest

reestablishment after fire (Brown & Wu 05)

7) Generally defined by sequences, not points in time;

8) Often defined by multiple variables (e.g., drought and T,

in conifer dieback of 2000 ff.)

9) And by cascades, which may involve other organisms

Drought, high T beetle outbreaks conifer death

Reduced CH status

Increased CO2 Altered T regime Frost damage in eucalypts

Altered frost sensitivity

KH Raffa et al., BioScience 58(2008): 501-517

JL Lutze et al., Plant, Cell and Environment (1998) 21, 631–635

Extreme events are…

……

7) Generally defined by sequences, not points in time;

8) Often defined by multiple variables (e.g., drought and T,

in conifer dieback of 2000 ff.)

9) And by cascades

10 Because of sequence-dependence, multiple correlated drivers,

and cascades: challenging to describe statistically

-even if only observationally, much less, predictively

For defined sequences: ARIMAs, etc.

Who knows the important sequences, as for frost damage?

Can GCMs do adequate statistics of extremes in drivers?

Challenging, even with rainfall timing

Simple observations: now finding heavy tails in floods – other

surprises waiting?A Dai & KE Trenberth, J. Climate 17(2004): 930-951

Extreme events are…

……

7) Generally defined by sequences, not points in time;

8) Often defined by multiple variables (e.g., drought and T,

in conifer dieback of 2000 ff.)

9) And by cascades

10) Because of sequence-dependence, multiple correlated drivers,

and cascades: hard to do statistics upon

11) Changing in spectrum

A) Drivers themselves, as shifts in PDFs – e.g., extremes in precipitation

Annual amounts, or heavy events

B) Crossing thresholds – recasting of even the form of PDFs

Non-analog climates

Thermohaline circulation shutdown in past, and perhaps in future

New “normals” can constitute extremes for extant genotypes

JW Williams & ST Jackson, Front Ecol Environ 5(2007): 475-482

Extreme events are…

……

8, 9, 10) Often defined by multiple variables, cascades challenging

statistics

11) Changing in spectrum

12) Thus, challenging to predict for effects

E.g, “March of the trees” with rising CO2 & climate change:

A) Potential effects on radiative balance and biogeochemical fluxes

B) Responses are in physiological time, of the individual organism:

May depend as much on extremes as on means

New climate regimes (non-analog climates) may constitute extreme

Physiological & ecological responses to EEs: poorly known

Acclimation is response - may reach limits in rates (Rubisco activase

in maize) or amounts dysacclimation as a definable extreme)

Direct responses to CO2 :poorly known, and extremely

variable potential biogeographic chaos

SJ Crafts-Brandner & ME Salvucci, Plant Physiol. 129(2002): 1773-1780

VP Gutschick, Ecol Mod 200 (2007): 433–451

Extreme events are…

…

12) Thus, challenging to predict for effects

A, B) radiative balance, biogeochemical fluxes; physiological time

C) Response in evolutionary time – nuanced, at the very least:

Fitness effects are likely concentrated in extreme events

Responses are constrained by population genetic structure

Who says responses are adaptive?

Neutral theory of Kimura (1983 ff.)

Adaptive responses to high CO2 – almost all lost in 20 My – N dynamics

D) How good are our predictive capacities fordrivers of EEs?

Point events – observations (return times) – good

Correlated multiple variabales – in development

GCMs’ abilities to capture spectrum (PDF) of point events – fair

GCMs’ abilities to capture sequences that define EEs – unknown

Biotic effects, such as disease prevalence- !!

SD Gaines & MW Denny, Ecology 74 (1993): 1677-1692

JP Iorio et al., Climate Dyn. 23(2004): 243-258

Recap: lots of specifics to account for, lots of conceptual

and mathematical challenges

* Inordinately weighted in physiology / ecology / evolution / biogeochem cycles

* Diverse in origins * Diverse in scales of time & space

* Defined by organismal response, not drivers

* Likely more important than mean values * Can be positive, too

* Defined by sequences, not points; multiple variables; cascades

* Challenging for statistics * Changing in spectrum

* Challenging in knowing organismal responses, even for adaptiveness

* Challenging to capture proper statistics in their (meteorological…) drivers

We need observational tools, and, more so,

a comprehensive framework, with

* biology: physiology, ecology, evolution

* meteorology and climatology

* statistics

Who's going to plan it?

OR will we default and live with greater uncertainty

than we need to for prevention and amelioration?

PowerPoints available at:http://gcconsortium.com/agu08.ppt

and …/agu08long.ppt