Sea Surface Temperature anomalies during 1987 El Niño (SOURCE: IGOSS nmc ship, buoy & satellite data;

UPLIFTED CORAL REEFS AT HUON PENINSULA: Last Interglacial, ~ 125 ka

CORAL AND INSTRUMENTAL RECORDS OF ENSO SINCE 1880 all records treated with a year bandpass filter to reveal ENSO variability

GLOBAL SEA-LEVEL AND FOSSIL CORAL SAMPLES

~1.8 ‰

ENSO strength in living and fossil corals

Sea Surface Temperature anomalies during 1987 El Niño (SOURCE: IGOSS nmc ship, buoy & satellite data;

Laguna Pallcacocha, Ecuador (Moy et al., 2002)

Laminated sediments from Laguna Pallcacocha, Ecuador: Rodbell et al., 1999

(Moy et al., 2002) Ecuadorian lake sediment record:

LIVING AND HOLOCENE CORAL  18 O seasonal and 9pt binomial filter2.5-7 year bandpass filtered (Tudhope et al, unpublished) weak ENSO ‘GRADUAL’ or ‘ABRUPT’? strong ENSO

Plankton: proxy indicators of climate change in the ocean. Carbonate shells of foraminiferans (top left) and coccoliths (bottom left), and silica skeletons of diatoms (top right) and radiolarians (bottom right)

Stott et al, Nature, 2004

Cobb et al, Nature, 2003

PALAEO ENSO: What we are pretty sure about: 1.Zonal E-W SST gradient initiated about 2-3 Myrs BP 2.Interannual ENSO variability present by 130 kyrs BP (possibly much earlier) 3.ENSO variability occurs in both ‘glacial’ and ‘interglacial’ conditions, but Modern ENSO appears to be relatively strong 4.ENSO was weak or absent in early-mid-Holocene (~10-6 kyrs BP)

PALAEO ENSO: What we still argue about: 1.What were mean conditions like in the equatorial Pacific during early-mid-Holocene when ENSO was weak ….. El Niño-like? …. La Niña-like?.... or neither? 2.Just how weak was the early-mid-Holocene ENSO? …. Separating SST from rainfall and salinity effects. 3.Glacial ENSO variability. 4.Relationship between interdecadal (PDO) variability, ENSO variability and mean state. 5.Relatonship, if any, between changes in mean conditions in the tropical Pacific and millennial variability in the extratropics, e.g., SW US drought in the MWP; D-O cycles in Greenland

Koutavas and Lynch-Stieglitz, 2004 When ENSO was weak in the early- mid-Holocene, what were mean conditions like in the equatorial Pacific?

PD: std. dev. = 0.81°C MH: std. dev. = 0.71°C

Palaeo-ENSO Work of: Tudhope et al, 2001; Ravelo et al., 2004, Moy et al., 2003, Cobb et al., 2003 Koutavas and Lynch-Stieglitz, 2004 Linsley et al., 2006, 2008

Ravelo et al, Nature, 2004 Development of equatorial zonal SST gradient about 2 million years ago:

ENVIRONMENTAL RECORDS FROM MASSIVE CORALS:

WHAT WE WOULD LIKE TO RECONSTRUCT: VARIANCE …. interannual-interdecadal BACKGROUND STATE of the tropical Pacific TELECONNECTION PATTERNS ….. extra-tropical and extra-Pacific a)Within ‘climate regime’ … little or no change in external forcing, e.g., late Holocene b)Between ‘climate regimes’ ….. significant changes in climatic boundary conditions, e.g., glacial vs. interglacial

ENSO ARCHIVES: Ideal attributes: 1.seasonal resolution 2.continuous 3.from core regions of ENSO dynamics Potential Archives (and attributes met): deep sea sediments (2, 3) laminated sediments, marine and lacustrine (?1, 2, ?3) tropical ice cores (1, 2) trees (1, 2) cave deposits (?1, 2, ?3) corals (1, 3)