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

Reid & Miller (1989) the Scientific Basis for Conserving Biodiversity, World Resources Institute; Vitousek (1994) Ecology 75: ; 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 Goldewijk and Battjes (1997) Reid & Miller (1989) Vitousek (1994) NOAA Global Change J.A. Klein

But climate and CO 2, 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 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 Cycle Evolution of the fraction of total emissions that remain in the atmosphere Total CO 2 emissions Atmosphere CO 2 Partitioning (PgC y -1 ) Time (y)

Fraction of total CO 2 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

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 (PgC) atmospheric CO 2 ocean land fossil fuel emissions deforestation (Residual) Sink Source Time (y) CO 2 flux (PgC y -1 ) 2.3±0.4 (5 models) 4.1± ± ±

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 Fossil Fuel Emission (PgCy -1 ) Full range of IPCC individual scenarios used for climate projections A1B Models Average A1FI Models Average A1T Models Average A2 Models Average B1 Models Average B2 Models Average Observed Projected 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 Some examples: Reassessing what we “know”…

Novel interactions Biotic change (species introductions) Abiotic change (Climate change and resource alterations)

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” CO 2 N H 2 O

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 Hypothesis Bonanza Creek LTER Total Area Burned Fire Season

Gradual warming Shift in Bark Beetle life cycle from 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 CO 2 CH 4 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: 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  genes Biotic Interactions Competition Herbivory Predation Mutualisms Biotic Constraints 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. economic Urgent vs. best science?