PAGES 2k — LLMpedia

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PAGES 2k is an international paleoclimatology initiative coordinating multi-proxy reconstructions of regional and global climate over the last two millennia. Started under the aegis of Past Global Changes (PAGES), the project brought together teams from institutions such as the University of Bern, the National Oceanic and Atmospheric Administration, the British Antarctic Survey, the Max Planck Institute for Meteorology, and the Scripps Institution of Oceanography to synthesize proxy records. Drawing on collaborations with projects at the Smithsonian Institution, the European Geosciences Union, the American Geophysical Union, the World Meteorological Organization, and national academies, it aimed to refine estimates used in assessments by the Intergovernmental Panel on Climate Change.

Background and objectives

PAGES 2k emerged from community efforts including contributors from the International Union for Quaternary Research, the National Science Foundation, the Royal Society, and the Academia Sinica to address debates sparked by reconstructions by teams at the University of East Anglia, the National Center for Atmospheric Research, the Hadley Centre, and the Lamont–Doherty Earth Observatory. Objectives included compiling regional proxy networks used by authors associated with the IPCC Fifth Assessment Report, informing syntheses like reports by the United Nations Environment Programme, and providing datasets comparable to instrumental records from organizations such as NASA and the European Centre for Medium-Range Weather Forecasts.

PAGES 2k employed statistical techniques developed at centers like the Princeton University and the University of Oxford and used proxies from archives curated by the British Library, the National Museum of Natural History (France), the Chinese Academy of Sciences, and the Australian National University. Data types included tree rings from networks coordinated with the International Tree-Ring Data Bank, speleothems collected by teams affiliated with the University of Innsbruck and the University of Arizona, coral cores studied at the Woods Hole Oceanographic Institution and the Australian Institute of Marine Science, and ice cores sampled by collaborations with the British Antarctic Survey and the Alfred Wegener Institute. Synthesis methods referenced work from statisticians at the University of Washington and climate modelers at the Geophysical Fluid Dynamics Laboratory, comparing proxy-inferred temperatures with outputs from the Coupled Model Intercomparison Project ensembles and reanalyses like those produced by ECMWF.

PAGES 2k publications reported regional reconstructions aligning or contrasting with earlier studies by researchers at the University of Colorado Boulder, the University of Toronto, the University of Cambridge, and the University of California, Berkeley. Findings included multi-centennial variability documented alongside events like the Medieval Warm Period and the Little Ice Age, interpreted in the context of forcings studied by teams at the National Aeronautics and Space Administration and the NOAA Geophysical Fluid Dynamics Laboratory. The syntheses influenced evaluations by the IPCC and informed comparisons with instrumental datasets from agencies such as NOAA, NASA, and national meteorological services including the Met Office and Météo-France.

Regional analyses covered continents and ocean basins with contributions from groups at the University of Auckland, the University of Cape Town, the University of Helsinki, the Russian Academy of Sciences, the Pontifical Catholic University of Chile, and the University of São Paulo. Temporal patterns identified by PAGES 2k teams paralleled paleoclimate records researched by the Smithsonian Tropical Research Institute and the Carnegie Institution for Science, showing asynchronous warming and cooling across regions studied by paleoclimatologists at the University of Stockholm, the University of Tokyo, and the University of Göttingen. Reconstructions extended to subregions such as the North Atlantic, the Pacific Ocean, Europe, Asia, Africa, South America, and Oceania with time-slice analyses aligning with volcanic forcing chronologies from the International Research Institute for Climate and Society and solar irradiance reconstructions by groups at the National Center for Atmospheric Research.

PAGES 2k supplied evidence used in policy-relevant assessments by the Intergovernmental Panel on Climate Change, informing risk analyses by the United Nations Framework Convention on Climate Change and adaptation planning referenced by the World Bank and the United Nations Development Programme. Its reconstructions provided context for attribution studies carried out at the Lawrence Berkeley National Laboratory and the Paul Scherrer Institute, and fed into climate model evaluation at the Max Planck Institute for Meteorology and the Geophysical Fluid Dynamics Laboratory, influencing projections used by agencies such as NASA and NOAA for scenario planning.

Critiques of PAGES 2k appeared in discussions involving scholars from the University of Massachusetts Amherst, the University of California, Santa Cruz, the University of Washington, and the University of Colorado, focusing on proxy selection, statistical methodology developed by teams at Princeton University and Carnegie Mellon University, and regional coverage debated by researchers at the University of Bern and the University of Copenhagen. Uncertainties highlighted include dating issues in records from the National Oceanography Centre, proxy sensitivity examined by investigators at the University of Arizona and the University of Queensland, and calibration choices compared with instrumental datasets from NOAA and NASA. Ongoing work by laboratories at the Swiss Federal Institute of Technology in Zurich, the Chinese Academy of Sciences, the Max Planck Institute for Meteorology, and the British Antarctic Survey aims to reduce these uncertainties.