Published on August 30, 2007
"A Globally Coherent Fingerprint of Climate Change Impacts across Natural Systems" Friday, January 31, 2003 : 'A Globally Coherent Fingerprint of Climate Change Impacts across Natural Systems' Friday, January 31, 2003 GARY W. YOHE CAMILLE PARMESAN WESLEYAN UNIVERSITY UNIVERSITY OF TEXAS - AUSTIN A Globally Coherent Fingerprint of Climate Change Impacts across Natural Systems: A Globally Coherent Fingerprint of Climate Change Impacts across Natural Systems Camille Parmesan andamp; Gary Yohe January 31, 2003 Center for Integrated Study of the Human Dimensions of Global Change, IPCC and Degrees of Confidence: IPCC and Degrees of Confidence Quantitative Scale: 95% or greater Very High Confidence 67-95% High Confidence 33-67% Medium Confidence 5 – 33% Low Confidence Less than 5% Very Low Confidence IPCC and Degrees of Confidence: IPCC and Degrees of Confidence Qualitative Scale: Well Established – Lots of evidence; high consensus Established but Incomplete – high consensus on limited information Competing Explanations – Lots of evidence; alternative explanations Speculative – Little evidence and many plausible explanations The IPCC Dynamic: The IPCC Dynamic 'We have very high confidence that X might happen!' 'We have medium to low confidence that X will happen!' Converged to the notion that the statements should speak to the 'will' alternative for a baseline. Observed Changes in Physical and Ecological Systems (from IPCC 2001): Observed Changes in Physical and Ecological Systems (from IPCC 2001) hydrology / sea ice animals plants study covers study based on glaciers large area remote sensing Key Conclusions from IPCC: Key Conclusions from IPCC Recent Regional Climate Changes, particularly Temperature Increases, have Already Affected Many Physical and Biological Systems (high confidence, or andgt;67% sure) Biotic change: 44 regional studies, 400 plants and animals, 20 to 50 years Physical change: 16 regional studies, 100 processes, 20-150 yrs non-polar glacier retreat reduction in Arctic sea ice extent and thickness in summer earlier plant flowering and longer growing season in Europe poleward and upward (elevation) migration of plants, insects and animals earlier bird arrival and egg laying increased incidence of coral bleaching increased economic losses due to extreme weather events Slide8: 1 2 3 4 5 Risks to unique andamp; threatened systems Risks to Some Risks to Many Increase Large increase Risk of extreme weather events Distribution of impacts Negative for some regions Negative for most regions Aggregate impacts Net Negative in All Metrics Positive or Negative Monetary; Most People Adversely Affected Very low Higher Risks of large scale discontinuities 0 O b s e r v a t i o n s -0.7 Increase in Global Mean Temperature after 1990 (°C) Figure 19-8-1: Summary of Lines of Evidence The “Global Fingerprint” was a “Reason for Concern”: The 'Global Fingerprint' was a 'Reason for Concern' The degree of confidence issue was contentious. Lisbon authors’ meeting: Chapter 2 – Tools discussion – how to judge? Chapter 5 – Ecosystems – Of course this is 'very high' Confidence Chapter 19 – Include in the burning ember, but with confidence 'medium' at best or 'very high' ??? A Schematic Portrait of the Problem: A Schematic Portrait of the Problem Study 1 Study 2 ……………… Study n Climate Climate Climate Change Change Change Impact Impact Impact Non- Non- Non- Climatic Climatic Climatic Factors Factors Factors A Thought Exercise: A Thought Exercise Let there be n separate studies. Let n’ produce results that are contrarian with respect to predicted climate impacts. Let p be the probability that there are explanations that compete with climate in any single study. Let pi be the likelihood that climate was corrected attributed as the cause in any study. Contours for “More Likely than Not”: Contours for 'More Likely than Not' Contours for Low and High Confidence: Contours for Low and High Confidence Complications: Complications Common Drivers of Non-climatic Drivers – Raises the contours. Studies that Show Sign Changes – Lowers the contours. Publication Bias against Contrary or Insignificant results – Increases the (n’/n) ratio. Slide15: New Analyses of changes from literature Studies with andgt; 20 years data Primarily multi-species - Counteracts publishing bias highlighting only species which show significant change Mostly multi-site (moderate to large geographic coverage) Conducted in nature reserve or rural natural area - minimizes chances of confounding factors (brings p closer to 1) Biotic Changes are Systematically in accord with Climate Change Predictions: Biotic Changes are Systematically in accord with Climate Change Predictions Diverse species of: trees, herbs, shrubs, reptiles, amphibians, fish, marine zooplankton andamp; invertebrates, mammals, birds butterflies (Parmesan andamp; Yohe, Nature 2003) Edith’s Checkerspot (Euphydryas editha): Edith’s Checkerspot (Euphydryas editha) Edith’s Checkerspot butterfly:Patterns of Population Extinctions in natural areas (good habitat): Edith’s Checkerspot butterfly: Patterns of Population Extinctions in natural areas (good habitat) Climatic Connections: USA: Climatic Connections: USA 0.7º C warming over Western USA climatic shift of 105 km North andamp; 105 m up (Karl et al. 1996) E. editha: mean location shifted 92 km North andamp; 124 m up (Parmesan 1996) Both snowpack andamp; E. editha extinction trends shift at 2400 m: % snow/50 yrs % extinctions Below 2400 m 14 % less snowpack ; melt 7 d earlier 46 % Above 2400 m 8 % more snowpack ; no melt 14 % (T. Johnson, 1998) Climate and E. editha : literature: Climate and E. editha : literature Ehrlich, Evolution ‘65 Singer, Ph.D. dissertation Stanford ‘71 Singer, Science ‘72, Singer andamp; Ehrlich, Fortschritte der Zoologie ‘79 Ehrlich et al., Oecologia ‘80 White andamp; Levin, Amer. Midland Natur. ‘80 MacKay Ecology ‘85 MacKay, Res. Pop. Ecol. ‘85 Singer, Evolution ‘83 Murphy andamp; White, Pan. Pacific Entomol. ‘84 Dobkin et al., Oecologia ‘87 Weiss et al, Oikos ‘87 Weiss et al, Ecology ‘88 Moore, Ecology ‘89 Parmesan, Ph.D dissertation ‘95 Boughton, Ecology ‘99 Boughton, Ph.D dissertation ‘99 Weiss et al, Oecologia ‘93 Foley et al., Singer andamp; Thomas, American Naturalist ‘96 Thomas et al., American Naturalist ‘96 Parmesan, Nature ‘96 Hellman, book ch. Fleishman et al. J. Res. Lep. Singer, in press McLaughlin et al. 2000 ATTRIBUTION by INFERENCE Example: Euphydras editha butterfly: ATTRIBUTION by INFERENCE Example: Euphydras editha butterfly Correlational Patterns Long-term patterns (100 years) --- range shift matches temperature isotherm shift and matches patterns of snowpack dynamics (Parmesan 1996, Karl et al. 1996, Johnson 1998) 'natural experiments' (40 years) --- below 2400 m, population extinctions occur in drought years and following false springs (light snowpack). Above 2400m, booms occur with heavy snowpack (Singer andamp; Ehrlich 1979, Singer andamp; Thomas 1996, McLaughlin et al. 2002) Field Manipulations manipulating thermal environment (slope aspect, habitat type) affects larval growth rates, pupal times, synchrony with host plant, and colonization success (Singer 1972, Weiss et al. 1988, 1993,, Boughton 1999) Laboratory Experiments temperature increases larval growth rates (Weiss et al 1988, Hellmann 2000) Thought Exercise revisited: Thought Exercise revisited p = Probability of competing explanations (confounding factors) π = Probability that observed change is really due to climate (mechanistic link) n’/n = Proportion of species going in opposite direction to climate change predictions Binomial probability model with each factor varying from 0 to 1 Here, p=0 Diagnostic Biological Fingerprint : Diagnostic Biological Fingerprint Temporal - Advancement of timing or northward expansion in warm decades (1930s/40s andamp; 1980s/'90s) - Delay of timing or southward contraction in cool decades (1950s/'60s) Spatial Different behaviors at extremes of range boundary during particular climate phase, e.g. expansion at northern range boundary simultaneous with contraction at southern range boundary during warming period Community Abundance changes have gone in opposite directions for cold-adapted vs. warm-adapted species. e.g. lowland birds increasing and montane birds decreasing at mid-elevation site. Diagnostic Biological Fingerprint : Diagnostic Biological Fingerprint 'Sign-Switching' found for 294 species 80% of abundance shifts in communities 100% follow decadal trends in temperatures (up andamp; down) 100% show geographic contraction at equatorial boundary coupled with expansion at poleward boundary of species range Increases confidence from either perspective (Parmesan andamp; Yohe 2003) Conclusions : Conclusions We have high to very high confidence that regional climate changes (resulting from global warming) have had impacts on wild species Observed changes are typically small in magnitude, but are likely to be an important factor in long-term persistence of species and stability of ecosystems More Conclusions from a Skeptical Perspective: More Conclusions from a Skeptical Perspective The thought exercise allows an approach that accommodates maximum skepticism. Even then, the Medium Confidence can be claimed. Indeed, Schneider’s 'more likely than not' benchmark is satisfied. Adding sign-switching adds to the power and moves even a skeptical interpretation in the High Confidence range.