Unprecedented recent warming of surface temperatures in the eastern tropical Pacific Ocean

Conroy, Jessica L.; Restrepo, Alejandra; Overpeck, Jonathan T.; Steinitz‐Kannan, Miriam; Cole, Julia E.; Bush, Mark B.; Colinvaux, Paul A.

doi:10.1038/ngeo390

Cited by 141 publications

(160 citation statements)

References 21 publications

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“…It is important to point out that some regional proxy records appear to be at odds with the idea of cool SSTs in the central-eastern tropical Pacific during medieval time Conroy et al 2008b). These include the records from Laguna Pallcacocha in the equatorial Andes (Moy et al 2002; high inflow events recorded in sediment), and from Quelccaya Ice Cap in southern Peru (d 18 O; Thompson et al 1984).…”

Section: Proxy Recordsmentioning

confidence: 99%

“…5I) and reconstructed eastern equatorial Pacific SSTs ( Fig. 5G; Conroy et al 2008b), though the modern relationship between these variables is weak (not shown). Comparison of Ghana lake level proxy records (Shanahan et al 2009) and the Peru river discharge proxy (Rein et al It is worth noting that regional precipitation gradients are strong, and water balance studies (Turner et al 1996;Shanahan et al 2007) demonstrate that declines in lake level like those indicated for Lake Bosumtwi during the MCA could result from modest persistent reductions in average precipitation (*5%, well within the range of modern variability in local rainfall), so medieval changes in regional precipitation may well have been relatively subtle.…”

Section: Proxy Recordsmentioning

confidence: 99%

“…3B). All records are Z-scores with offset for display, ordinate gridlines are separated by 3r the post-1100 AD period, reconstructed SSTs from the central and eastern equatorial Pacific indicate MCA SSTs averaged *0.7-0.8°C cooler than the modern pre-1970 average (Cobb et al 2003;Conroy et al 2008b; Fig. 3O, P; Fig.…”

Section: Proxy Recordsmentioning

confidence: 99%

“…F Western equatorial Pacific/Indonesian SST anomaly (red; Oppo et al 2009; also Newton et al 2006). G Eastern equatorial Pacific SST anomaly (orange; Conroy et al 2008b). H Sierra Nevada (California) Sequoia grove fire scar frequency (blue with circles; Swetnam 1993).…”

Section: Proxy Recordsmentioning

confidence: 99%

“…The idea of coherent large-scale changes in circulation over the North Pacific received additional attention with the development of evidence from fossil coral records, as well as marine and lacustrine sediments which consistently point to cooler sea surface temperatures (SSTs) and significantly drier conditions in the central and eastern equatorial Pacific during the MCA (Cobb et al 2003;Rein et al 2004;Conroy et al 2008b). Given the well established associations between winter North Pacific circulation patterns, cool season precipitation over the western US, and interannual-to-interdecadal SST variability in the tropical Pacific (Bjerknes 1969;Lau 1985;Schonher and Nicholson 1989;Mantua et al 1997;Rajagopalan et al 2000), the proxy evidence is consistent with the idea that MCA aridity in the American West (and contraction of the Aleutian Low) was a response, at least in part, to cooler central and eastern tropical Pacific SSTs.…”

Section: Introductionmentioning

confidence: 99%

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Support for global climate reorganization during the “Medieval Climate Anomaly”

et al. 2010

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Widely distributed proxy records indicate that the Medieval Climate Anomaly (MCA; *900-1350 AD) was characterized by coherent shifts in large-scale Northern Hemisphere atmospheric circulation patterns. Although cooler sea surface temperatures in the central and eastern equatorial Pacific can explain some aspects of medieval circulation changes, they are not sufficient to account for other notable features, including widespread aridity through the Eurasian sub-tropics, stronger winter westerlies across the North Atlantic and Western Europe, and shifts in monsoon rainfall patterns across Africa and South Asia. We present results from a full-physics coupled climate model showing that a slight warming of the tropical Indian and western Pacific Oceans relative to the other tropical ocean basins can induce a broad range of the medieval circulation and climate changes indicated by proxy data, including many of those not explained by a cooler tropical Pacific alone. Important aspects of the results resemble those from previous simulations examining the climatic response to the rapid Indian Ocean warming during the late twentieth century, and to results from climate warming simulations-especially in indicating an expansion of the Northern Hemisphere Hadley circulation. Notably, the pattern of tropical Indo-Pacific sea surface temperature (SST) change responsible for producing the proxy-model similarity in our results agrees well with MCA-LIA SST differences obtained in a recent proxy-based climate field reconstruction. Though much remains unclear, our results indicate that the MCA was characterized by an enhanced zonal Indo-Pacific SST gradient with resulting changes in Northern Hemisphere tropical and extra-tropical circulation patterns and hydroclimate regimes, linkages that may explain the coherent regional climate shifts indicated by proxy records from across the planet. The findings provide new perspectives on the nature and possible causes of the MCA-a remarkable, yet incompletely understood episode of Late Holocene climatic change.

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Section: Proxy Recordsmentioning

confidence: 99%

Section: Proxy Recordsmentioning

confidence: 99%

Section: Proxy Recordsmentioning

confidence: 99%

Section: Proxy Recordsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Support for global climate reorganization during the “Medieval Climate Anomaly”

et al. 2010

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Mount Logan ice core record of tropical and solar influences on Aleutian Low variability: 500–1998 A.D.

et al. 2014

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Continuous, high-resolution paleoclimate records from the North Pacific region spanning the past 1500 years are rare; and the behavior of the Aleutian Low (ALow) pressure center, the dominant climatological feature in the Gulf of Alaska, remains poorly constrained. Here we present a continuous, 1500 year long, calibrated proxy record for the strength of the wintertime (December-March) ALow from the Mount Logan summit (PR Col; 5200 m asl) ice core soluble sodium time series. We show that ice core sodium concentrations are statistically correlated with North Pacific sea level pressure and zonal wind speed. Our

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Holocene variability in the intensity of wind-gap upwelling in the tropical eastern Pacific

et al. 2015

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Wind-driven upwelling in Pacific Panamá is a significant source of oceanographic variability in the tropical eastern Pacific. This upwelling system provides a critical teleconnection between the Atlantic and tropical Pacific that may impact climate variability on a global scale. Despite its importance to oceanographic circulation, ecology, and climate, little is known about the long-term stability of the Panamanian upwelling system or its interaction with climatic forcing on millennial time scales. Using a combination of radiocarbon and U-series dating of fossil corals collected in cores from five sites across Pacific Panamá, we reconstructed the local radiocarbon reservoir correction, ΔR, from~6750 cal B.P. to present. Because the ΔR of shallow-water environments is elevated by upwelling, our data set represents a millennial-scale record of spatial and temporal variability of the Panamanian upwelling system. The general oceanographic gradient from relatively strong upwelling in the Gulf of Panamá to weak-to-absent upwelling in the Gulf of Chiriquí was present throughout our record; however, the intensity of upwelling in the Gulf of Panamá varied significantly through time. Our reconstructions suggest that upwelling in the Gulf of Panamá is weak at present; however, the middle Holocene was characterized by periods of enhanced upwelling, with the most intense upwelling occurring just after of a regional shutdown in the development of reefs at~4100 cal B.P. Comparisons with regional climate proxies suggest that, whereas the Intertropical Convergence Zone is the primary control on modern upwelling in Pacific Panamá, the El Niño-Southern Oscillation drove the millennial-scale variability of upwelling during the Holocene.

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Unprecedented recent warming of surface temperatures in the eastern tropical Pacific Ocean

Cited by 141 publications

References 21 publications

Support for global climate reorganization during the “Medieval Climate Anomaly”

Support for global climate reorganization during the “Medieval Climate Anomaly”

Mount Logan ice core record of tropical and solar influences on Aleutian Low variability: 500–1998 A.D.

Holocene variability in the intensity of wind-gap upwelling in the tropical eastern Pacific

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