Final 2 weeks of class…

Final exam will be posted on-line next week…

Next week - Dale Lockwood: The “should ecologists be neutral or advocates” debate…

What is “Global Change”?

Established in 1989 and codified in 1990 by the Global Change Research Act

An Act - To require the establishment of a United States Global Change Research Program aimed at understanding and responding to global change, including the cumulative effects of human activities and natural processes on the environment, to promote discussions toward international protocols in global change research, and for other purposes.

Global change—”changes in the environment that may alter the capacity of the Earth to sustain life”

Time series of departures from the 1961 to 1990 base period for an annual mean global temperature of 14.0°C (bars) and for a carbon dioxide mean of 334 ppmv (solid curve) during the base period, using data from ice cores and (after 1958) from Mauna Loa (4). Many other factors (such as the effects of volcanic eruptions and solar irradiance changes) are also important. (Karl and Trenberth 2003)

What most people hear when you say Global Change (Global warming or increasing air temperatures…)

Dave Theobald

Dave Theobald

Reid & Miller (1989) the Scientific Basis for Conserving Biodiversity, World Resources Institute; Vitousek (1994) Ecology 75:1861-1876;

National Oceanic and Atmospheric Administration (NOAA), USA. (Slide courtesy of Berrien Moore, USA)

Climate change is only one aspect of Global Change

D. Wall

Ecological Systems

Go

lde

wijk

an

d

Ba

ttjes

(19

97

)

Re

id &

Mille

r (1

98

9)

Vitousek (1994)

NOAA

Global Change

J.A. Klein

But climate and CO2, biodiversity and even land cover have varied in the past. Can’t we learn from

the past? Paleoclimatic Studies

• Understanding how earth systems (biotic and physical) have changed on a range of time scales in the past can help us understand what the future may hold. But….

Overpeck et al. 2003

The past can provide insight, but history provides few analogs for the type of climate change forecast…

IPCC predictions

Ecological world today• new global drivers of change• rapid pace of change

Global change “heading towards the unknown”

Ecological world in textbooks• natural systems in equilibrium• local disturbance drives change

Local change within a “backdrop of the known”

Is the situation likely to get any better?

Updated from Le Quéré et al. 2009, Nature Geoscience; Data: NOAA 2010, CDIAC 2010

Key Diagnostic of the Carbon CycleEvolution of the fraction of total emissions that remain in the atmosphere

Total CO2 emissions

Atmosphere

CO2 P

artit

ioni

ng (P

gC y

-1)

1960 20101970 1990 20001980

10

8

6

4

2

Time (y)

Fraction of total CO2 emissions that remains in the atmosphere

Airborne Fraction

Updated from Le Quéré et al. 2009, Nature Geoscience; Raupach et al. 2008, Biogeosciences; Canadell et al. 2007, PNAS

Airb

orne

Fra

ctio

nTrend: 0.31 % y-1

(p=~0.9)45%

1960 20101970 1990 20001980

1.0

0.8

0.6

0.4

0.2

40%

Time (y)

Human Perturbation of the Global Carbon Budget

Global Carbon Project 2010; Updated from Le Quéré et al. 2009, Nature Geoscience; Canadell et al. 2007, PNAS

5

10

10

5

1850 1900 1950 2000

2000-2009(PgC)

atmospheric CO2

ocean

land

fossil fuel emissions

deforestation

(Residual)

Sink

Sour

ce

Time (y)

CO2 f

lux

(PgC

y-1)

2.3±0.4(5 models)

4.1±0.1

7.7±0.5

1.1±0.7

2.4

Fossil Fuel Emissions: Actual vs. IPCC Scenarios

Updated from Raupach et al. 2007, PNAS; Data: Gregg Marland, Thomas Boden-CDIAC 2010; International Monetary Fund 2010

Foss

il Fue

l Em

issio

n (Pg

Cy-1)

5

6

7

8

9

10

1990 1995 2000 2005 2010 2015

Full range of IPCC individual scenarios used for climate projections

A1B Models AverageA1FI Models AverageA1T Models AverageA2 Models Average

B1 Models AverageB2 Models Average

ObservedProjected

Time (y)

• Appreciate that drivers “then” and drivers “now” may differ…• Re-assess as well as push forward…• Take advantage of this “global experiment”…

Hang on tight…

As Ecologists, what do we do?

No one is saying that this will be easy…

Opportunities afforded by Global Change that did not exist previously (when Ecology was “easy”)

“The rates, scales, kinds, and combinations of changes occurring now are fundamentally different from those at any other time in history…”

- Vitousek et al. 1997

Some examples: Reassessing what we “know”…

Novel interactions

Biotic change (species introductions)

Abiotic change (Climate change and resource alterations)

Resources

Biota

A. Disturbance

Resources

Biota

B. Global Change

Chronic resourcealteration

Discretedisturbance

Moving from a “disturbance centric” to a global change world

Global change leads directly to resource alterations – new types of drivers of ecological dynamics.

Define “Disturbance”

CO2

N H2O

Gradual change does not mean gradual response – responses are occurring quickly…

Thresholds and alternative stable states have always existed, but thresholds are being crossed more frequently and alternative states are more commonly manifest today…

Desertification…

Direct Climate Change HypothesisBonanza Creek LTER

Tota

l A

rea B

urn

ed

Fire Season

Gradual warming

Shift in Bark Beetle life cyclefrom two years to one –threshold response…

Outbreak dynamics

Increased fuel loads

Indirect effect of warming

Direct effect

Biotic Interactions can accelerate responses to climate change…

Permafrost loss in the Arctic: another threshold response

CO2

CH4

Warmer temperatures

Unfrozen Frozen

Microbial decomposition of stored Carbon

Biotic Interactions can feedback on drivers…

Evaluating Controls on Productivity in Ecosystems: Can we use successful exotic invasive species to learn more about abiotic controls and biotic constraints on productivity? (the Dov Sax approach: (2007) Trends in Ecology and Evolution 22:465-471 - Ecological and evolutionary insights from species invasions)

Exotic “bluestems” invading native grassland in Kansas

Response?

Herbicide…

A Nightmare for Long-term Experiments…

Can something “good” come out of something “bad”?

Productivity

Abiotic Drivers & Resources• Solar radiation• Temperature• Precipitation• Edaphic Factors Environmental• Nutrients Limitations

Community Gene Pool species genesBiotic Interactions

• Competition• Herbivory• Predation• Mutualisms

BioticConstraints

Traditional ecological manipulations

Invasive Exotic Species

Determinants of Productivity in Ecosystems

Autotrophs

A major challenge for research ecologists (you)…

There are more fundamentally important questions to answer and more problems to solve than we have ecologists or resources available ($)… or (gulp) time (?).

How do we prioritize?

What if you were the “Czar of Global Ecological Crises”? How would you decide?

-------------------------------------------------------------------------------------------Individual/Class exercise (Groups of 4)

Provide specific prioritizing criteria that you think we should use to determine what ecological research we fund and what we do not…

Rare vs. dominant?Unique vs. broadly applicable?Aesthetic vs. economicUrgent vs. best science?