Decadal-scale Climate Information

Transcription

1 Decadal-scale Climate Information Lisa Goddard International Research Institute for Climate & Society The Earth Institute of Columbia University Predicting the Climate of the Coming Decades Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA January 11-14, 2010

2 Acknowledgements & Reference: This presentation draws some material from the white paper and associated presentation from the World Climate Conference-3 (WCC3) Needs assessment for climate information on decadal time scales and longer led and presented by Carolina Vera With: M. Barange, O.P. Dube, L. Goddard, D. Griggs, N. Kobysheva, E. Odada, S. Parey, J. Polovina, G. Poveda, B. Seguin, K. Trenberth Thanks also to Near-Term Climate Change group at IRI: Arthur Greene, Bradfield Lyon, Alessandra Giannini, Andrew Robertson, Sylwia Trzaska, Kátia Fernandes, Liqiang Sun, and Joshua Qian and numerous collaborators both near and far

3 Main Points: Decadal-Scale Climate Information What do we mean? RANGE of TIME SCALES Seasonal-to-Interannual Variability Decadal Variability [Natural] Climate Change [Anthropogenic] Where are we? EARLY STAGES What challenges are we facing? MANY

4 Decadal Variability: A Sector-based Assessment LAND DEGRADATION AND FIRE MANAGEMENT WATER MANAGEMENT HEALTH ENERGY TRANSPORTATION AGRICULTURE AND FOOD PRODUCTION (Courtesy of C. Vera) MARINE FISHERIES AND ECOSYSTEMS

5 Information Needs for the science and for society Characterization of past observations How large are the decadal-scale fluctuations compared to trends and interannual variability? Attribution Will the current trend continue? Who is responsible? Prediction/projection Impact of increasing GHGs + evolution of low-frequency [natural] fluctuations in the climate system? How do these slow changes affect risks of climate impacts from year-to-year variability?

6 Hydropower and Decadal Climate Variability 1) Improving year-to-year management: How do decadal fluctuations modulate ENSO impacts in the region? 2) Long-term planning of water & energy contracts (typically 5-10 years): Can mean conditions for next 5-10 years be predicted within some level of confidence? Data Courtesy of R. Terra and A. Diaz

7 Timescales of Variability in Observations e.g. Climate Variability & Change in Florida Temperature Precipita>on 9% 5% 33% 17% 58% 78%

8 Decadal-scale Climate Predictions from IPCC-4? Western Africa : Annual-Mean Temperature Southern Africa : Annual-Mean Temperature Existing Climate Change Projections cannot deliver predictions of decadal variability

9 Planning for the Future Where are we? Good UNDERSTANDING and PREDICTABILITY Some Info Fron>er Seasonal-to -Interannual Decadal Timescale Climate Change Our understanding of climate variability and our ability to predict it is not constant across Cmescales. Predicting the Climate of the Coming Decades RSMAS -- January 11, 2010

10 PDO (Pacific Decadal OscillaCon) The principal mode in the Pacific POSITIVE Phase NEGATIVE Phase PDO refers mainly to N. Pacific sea surface temperatures (SSTs). Climate teleconnections similar to those of ENSO Substantial interannual variability Precipitation Correlation Several processes at work Meehl & Hu, J. Climate, 2006 (Source:

11 AMO (Atlantic Multi-decadal Oscillation) The principal mode in the Atlantic (Goldenberg et al. Science, 2001) Source:

12 AMO (Atlantic Multi-decadal Oscillation) The principal mode in the Atlantic NAO? (Goldenberg et al. Science, 2001) Atmos-Ocean Coupling? Have hypothesis of dominant mechanism, but what drives it? Weather? Air-sea coupling? (Vellinga and Wu, J. Climate, 2004)

13 Improving Decadal-scale Climate Predictions Need information about both man-made climate change & natural decadal variability Prospects: Dynamical Predictions: * Coupled Earth System Models with initialization of climate system, particularly the oceans * Include changing atmospheric composition Statistical Predictions: * Characterize observed decadal variability of the past * Include trends from models or statistics

14 Global Climate Change Projections Contribute to decadal climate, but don t contain correct ICs 2030 Source: IPCC 4 th Assessment Report, Working Group 1: The Physical Science Basis for Climate Change

15 Regional Patterns of Climate Change 20 th Century: Observed patterns of T & P trends agree better with models that have more realistic patterns of SST trends. (Shin and Sardeshmukh, Climate Dynamics, in press)

16 Prediction/Projection: GHGs + ICs Regionality? Ts projections improved over many regions (Smith et al. Science, 2007) Ratio of Externally-forced to Total Variance Regional T improvement bears striking resemblance to regions where T is dominated by externallyforced signal. Likely to give better regional estimates of anthropogenic trends (M. Ting et al, J.Climate, 2009)

17 Seasonal-to-Interannual Variability El Nino Sea Surface Temperature Anomalies Climate predictions, including El Nino and its associated impacts are probabilistic.

18 Variability & Uncertainty in Decadal-Scale Climate N.Atlantic Avg SST OBSERVED Uncertainty envelope may include range of values possible with addition of year-to-year variability ( climate noise ). Need to know intended timescale of information, what is being predicted, and what contributes to uncertainty. (Example provided by Keith Dixon)

19 Main Points: Decadal-Scale Climate Information What do we mean? RANGE of TIME SCALES Seasonal-to-Interannual Variability Decadal Variability [Natural] Climate Change [Anthropogenic] Where are we? EARLY STAGES Gaining understanding, developing hypotheses Observational Network only recently adequate, spatially Prediction experiments only recently initiated What challenges are we facing? MANY What are the dominant processes? To what extent are they predictable? How well do current models (& forecast systems) work? How best to present information that is both informative and actionable?

20 Recommendations from Sector Based Assessment In order to develop effective information, we must build effective partnerships linking stakeholders, decision makers, sectoral experts, and climate information providers (i.e. operational and research efforts on climate prediction, climate observations, and climate analysis).

21 Postdocs Applying Climate Expertise (PACE): A National Fellowship Program to Interface Climate & Society Contacts: Lisa Goddard (Chair Oversight Committee) goddard@iri.columbia.edu Meg Austin (Program Administrator) austin@ucar.edu

22 Thank you Predicting the Climate of the Coming Decades RSMAS -- January 11, 2010