NOAA Paleoclimatology What's New

The World Data Center for Paleoclimatology features newly archived paleoclimatic data and climate reconstructions relevant to important issues in paleoclimatology, plus new services we offer to the scientific community.

Please check our archived pages for What's New sections for the years: 2004, 2003, 2002, 2001, 2000, 1999, 1998, 1997, 1996, and 1995.

What's New for 2005:

	Insolation-driven changes in atmospheric circulation over the past 116,000 years in subtropical Brazil Cruz et al. Nature Vol. 434, No. 7029, pp. 63 - 66, 3 March 2005. During the last glacial period, large millennial-scale temperature oscillations-the 'Dansgaard/Oeschger' cycles-were the primary climate signal in Northern Hemisphere climate archives from the high latitudes to the tropics. But whether the influence of these abrupt climate changes extended to the tropical and subtropical Southern Hemisphere, where changes in insolation are thought to be the main direct forcing of climate, has remained unclear. Here we present a high-resolution oxygen isotope record of a U/Th-dated stalagmite from subtropical southern Brazil, covering the past 116,200 years. The oxygen isotope signature varies with shifts in the source region and amount of rainfall in the area, and hence records changes in atmospheric circulation and convective intensity over South America. We find that these variations in rainfall source and amount are primarily driven by summer solar radiation, which is controlled by the Earth's precessional cycle. The Dansgaard/ Oeschger cycles can be detected in our record and therefore we confirm that they also affect the tropical hydrological cycle, but that in southern subtropical Brazil, millennial-scale climate changes are not as dominant as they are in the Northern Hemisphere.
	Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data Moberg et al. Nature Vol. 433, No. 7026, pp. 613 - 617, 10 February 2005. A number of reconstructions of millennial-scale climate variability have been carried out in order to understand patterns of natural climate variability, on decade to century timescales, and the role of anthropogenic forcing. These reconstructions have mainly used tree-ring data and other data sets of annual to decadal resolution. Lake and ocean sediments have a lower time resolution, but provide climate information at multicentennial timescales that may not be captured by tree-ring data. Here we reconstruct Northern Hemisphere temperatures for the past 2,000 years by combining low-resolution proxies with tree-ring data, using a wavelet transform technique to achieve timescale-dependent processing of the data. Our reconstruction shows larger multicentennial variability than most previous multi-proxy reconstructions, but agrees well with temperatures reconstructed from borehole measurements and with temperatures obtained with a general circulation model. According to our reconstruction, high temperatures - similar to those observed in the twentieth century before 1990- occurred around AD 1000 to 1100, and minimum temperatures that are about 0.7K below the average of 1961-90 occurred around AD 1600. This large natural variability in the past suggests an important role of natural multicentennial variability that is likely to continue.
	High-latitude influence on the eastern equatorial Pacific climate in the early Pleistocene epoch Liu and Herbert Nature Vol. 427, No. 6976, pp. 720 - 723, 19 February 2004. Many records of tropical sea surface temperature and marine productivity exhibit cycles of 23 kyr (orbital precession) and 100 kyr during the past 0.5Myr, whereas high-latitude sea surface temperature records display much more pronounced obliquity cycles at a period of about 41 kyr. Little is known, however, about tropical climate variability before the mid-Pleistocene transition about 900 kyr ago, which marks the change from a climate dominated by 41-kyr cycles (when ice-age cycles and high-latitude sea surface temperature variations were dictated by changes in the Earth’s obliquity) to the more recent 100-kyr cycles of ice ages. Here we analyse alkenones from marine sediments in the eastern equatorial Pacific Ocean to reconstruct sea surface temperatures and marine productivity over the past 1.8Myr. We find that both records are dominated by the 41-kyr obliquity cycles between 1.8 and 1.2Myr ago, with a relatively small contribution from orbital precession, and that early Pleistocene sea surface temperatures varied in the opposite sense to local annual insolation in the eastern equatorial Pacific Ocean. We conclude that during the early Pleistocene epoch, climate variability at our study site must have been determined by high-latitude processes that were driven by orbital obliquity forcing.
	An unusually active Sun during recent decades compared to the previous 11,000 years. Solanki et al. Nature Vol. 431, No.7012, pp.1084-1087, 28 October 2004. Direct observations of sunspot numbers are available for the past four centuries, but longer time series are required, for example, for the identification of a possible solar influence on climate and for testing models of the solar dynamo. Here we report a reconstruction of the sunspot number covering the past 11,400 years, based on dendrochronologically dated radiocarbon concentrations. We combine physics-based models for each of the processes connecting the radiocarbon concentration with sunspot number. According to our reconstruction, the level of solar activity during the past 70 years is exceptional, and the previous period of equally high activity occurred more than 8,000 years ago. We find that during the past 11,400 years the Sun spent only of the order of 10% of the time at a similarly high level of magnetic activity and almost all of the earlier high-activity periods were shorter than the present episode. Although the rarity of the current episode of high average sunspot numbers may indicate that the Sun has contributed to the unusual climate change during the twentieth century, we point out that solar variability is unlikely to have been the dominant cause of the strong warming during the past three decades.
	Stable sea surface temperatures in the western Pacific warm pool over the past 1.75 million years de Garidel-Thoron et al. Nature Vol. 433, No.7023, 20 January 2005. About 850,000 years ago, the period of the glacial cycles changed from 41,000 to 100,000 years. This mid-Pleistocene climate transition has been attributed to global cooling, possibly caused by a decrease in atmospheric carbon dioxide concentrations. However, evidence for such cooling is currently restricted to the cool upwelling regions in the eastern equatorial oceans, although the tropical warm pools on the western side of the ocean basins are particularly sensitive to changes in radiative forcing. Here we present high-resolution records of sea surface temperatures spanning the past 1.75 million years, obtained from oxygen isotopes and Mg/Ca ratios in planktonic foraminifera from the western Pacific warm pool. In contrast with the eastern equatorial regions, sea surface temperatures in the western Pacific warm pool are relatively stable throughout the Pleistocene epoch, implying little long-term change in the tropical net radiation budget. Our results challenge the hypothesis of a gradual decrease in atmospheric carbon dioxide concentrations as a dominant trigger of the longer glacial cycles since 850,000 years ago. Instead, we infer that the temperature contrast across the equatorial Pacific Ocean increased, which might have had a significant influence on the mid-Pleistocene climate transition.
	Grape ripening as a past climate indicator Chuine et al. Nature Vol. 432, No.7015, 18 November 2004. French records of grape-harvest dates in Burgundy were used to reconstruct spring-summer temperatures from 1370 to 2003 using a process-based phenology model developed for the Pinot Noir grape. Our results reveal that temperatures as high as those reached in the 1990s have occurred several times in Burgundy since 1370. However, the summer of 2003 appears to have been extraordinary, with temperatures that were probably higher than in any other year since 1370.
	Antarctic Timing of Surface Water Changes off Chile and Patagonian Ice Sheet Response. Lamy et al. Science Vol. 304, No. 5679, pp.1959-1962, 25 June 2004. Marine sediments from the Chilean continental margin are used to infer millennial-scale changes in southeast Pacific surface ocean water properties and Patagonian ice sheet extent since the last glacial period. Our data show a clear "Antarctic" timing of sea surface temperature changes, which appear systematically linked to meridional displacements in sea ice, westerly winds, and the circumpolar current system. Proxy data for ice sheet changes show a similar pattern as oceanographic variations offshore, but reveal a variable glacier-response time of up to ~1000 years, which may explain some of the current discrepancies among terrestrial records in southern South America.

What's New for 2004:

Data from Jones and Mann Reviews of Geophysics , "Climate Over Past Millennia."
Data from Huang, Geophysical Research Letters , "Merging Information from Different Resources for New Insights into Climate Change in the Past and Future"
Data from Cook et al., Science, "Long-Term Aridity Changes in the Western United States"
Data from North Greenland Ice Core Project members, Nature, "High-resolution record of Northern Hemisphere climate extending into the last interglacial period"
Data from Stott et al., Nature, "Decline of surface temperature and salinity in the western tropical Pacific Ocean in the Holocene epoch."
Data from EPICA Community Members, Nature , "Eight glacial cycles from an Antarctic ice core"
A Paleo Perspective on Abrupt Climate Change
Data from Felis et al., Nature, "Increased seasonality in Middle East temperatures during the last interglacial period. "
Data from Yuan et al., Science, "Timing, Duration, and Transitions of the Last Interglacial Asian Monsoon."
Data from Schmidt et al., Nature, "Links between salinity variation in the Caribbean and North Atlantic thermohaline circulation "
Data from Hughen et al., Science, "¹⁴C Activity and Global Carbon Cycle Changes over the Past 50,000 Years"
Data from Flückiger et al., Global Biogeochemical Cycles , "N₂O and CH₄ variations during the last glacial epoch: Insight into global processes "
Data from Genty et al., Nature, "Precise dating of Dansgaard-Oeschger climate oscillations in western Europe from stalagmite data "

What's New for 2003:

Data from Ge et al., Holocene, "Winter half-year temperature reconstruction for the middle and lower reaches of the Yellow River and Yangtze River, China, during the past 2000 years."
Data from Williams et al., Ecological Monographs , "Late Quaternary vegetation dynamics in North America: scaling from taxa to biomes"
Spanish Version of Paleo Perspectives and Educational Outreach
Data from Booth and Jackson, Holocene, "A high-resolution record of late-Holocene moisture variability from a Michigan raised bog, USA"
Data from Lea et al., Science, "Synchroneity of Tropical and High-Latitude Atlantic Temperatures over the Last Glacial Termination"
International Multiproxy Paleofire Database
Data from Bar-Matthews et al., Geochimica et Cosmochimica Acta , "Sea-land oxygen isotopic relationships from planktonic foraminifera and speleothems in the Eastern Mediterranean region and their implication for paleorainfall during interglacial intervals"
Data from Pahnke et al., Science , "340,000-Year Centennial-Scale Marine Record of Southern Hemisphere Climatic Oscillation"
Data from Mann and Jones, Geophysical Research Letters , "Global Surface Temperatures over the Past Two Millennia"
Data from Tan et al., Geophysical Research Letters , "Cyclic rapid warming on centennial-scale revealed by a 2650-year stalagmite record of warm season temperature"
Data from Ammann et al., Geophysical Research Letters , "A monthly and latitudinally varying volcanic forcing dataset in simulations of 20th century climate"
Data from Cobb et al., Nature, "El Niño/Southern Oscillation and tropical Pacific climate during the last millennium"
Data from D'Arrigo et al., Geophysical Research Letters , "Tree-ring reconstructions of temperature and sea-level pressure variability associated with the warm-season Arctic Oscillation since AD 1650"
Data from Graumlich et al., Climatic Change , "Upper Yellowstone River Flow and Teleconnections with Pacific Basin Climate Variability during the Past Three Centuries"
Data from Touchan et al., International Journal of Climatology , "Preliminary reconstructions of spring precipitation in southwestern Turkey from tree-ring width"
Data from Cook et al., International Journal of Climatology , "Dendroclimatic Signals in Long Tree-Ring Chronologies from the Himalayas of Nepal"
Data from Friddell et al., Geophysical Research Letters , "Increased northeast Pacific climatic variability during the warm middle Holocene"
Data from Hantemirov and Shiyatov, Holocene , "A continuous multimillennial ring-width chronology in Yamal, northwestern Siberia"
Data from McCulloch et al., Nature, "Coral record of increased sediment flux to the inner Great Barrier Reef since European settlement"
Data from Mann et al., Journal of Geophysical Research -Atmospheres , "Optimal Surface Temperature Reconstructions Using Terrestrial Borehole Data"
The Climate TimeLine Information Tool

What's New for 2002:

Data from Woodhouse et al., Bulletin of the American Meteorological Society , "Drought in the Western Great Plains, 1845-56: Impacts and Implications"
Data from Ni et al., International Journal of Climatology, "Cool-season precipitation in the southwestern USA since AD 1000: comparison of linear and nonlinear techniques for reconstruction"
Data from Moore et al., Nature, "Climate change in the North Pacific region over the past three centuries"
Data from Noren et al., Nature , "Millennial-scale Storminess Variability in the Northeastern United States during the Holocene Epoch"
Data from Moy et al., Nature , "Variability of El Niño/Southern Oscillation activity at millennial timescales during the Holocene epoch"
Data from Thompson et al., Science , "Kilimanjaro Ice Core Records: Evidence of Holocene Climate Change in Tropical Africa"
Data from Yang et al., Geophysical Research Letters, "General characteristics of temperature variation in China during the last two millennia."
New WDC-Paleo Mirror Sites in China and India
Data from St. George and Nielsen, Quaternary Research , "Hydroclimatic change in southern Manitoba since A.D. 1409 inferred from tree rings."
Data from Cook et al., Journal of Climate , "A Well-Verified, Multiproxy Reconstruction of the Winter North Atlantic Oscillation Index since A.D. 1400"
Data from Benson et al., Quaternary Science Reviews , "Holocene multidecadal and multicentennial droughts affecting Northern California and Nevada"
Data from Anderson et al., Science , "Increase in the Asian SW Monsoon During the Past Four Centuries"
Data from Lloyd and Fastie, Climatic Change , "Spatial and temporal variability in the growth and climate response of treeline trees in Alaska"
Data from Lamy et al., Paleoceanography , "High- and low-latitude climate control on the position of the southern Peru-Chile Current during the Holocene."
Data from Viau and Gajewski, Journal of Geophysical Research-Atmosphere , "Holocene variations in the global hydrological cycle quantified by objective gridding of lake level databases"
Data from Schuster et al., Environmental Science and Technology , "Atmospheric Mercury Deposition during the Last 270 Years: A Glacial Ice Core Record of Natural and Anthropogenic Sources"
New Additions to the Software Library: PALYHELP and Arand.
Data from Flückiger et al., Global Biogeochemical Cycles , "High-resolution Holocene N₂O ice core record and its relationship with CH₄ and CO₂"
Data from Jones et al., Science , "The Evolution of Climate Over the Last Millennium"
Data from Luterbacher et al., Atmospheric Science Letters, "Extending North Atlantic Oscillation reconstructions back to 1500"
Data from Briffa et al., Journal of Geophysical Research, "Low-frequency Temperature Variations from a Northern Tree Ring Density Network"
Data from Andrus et al., Science , "Otolith d¹⁸O Record of Mid-Holocene Sea Surface Temperatures in Peru"
Data from Hendy et al., Science , "Abrupt Decrease in Tropical Pacific Sea Surface Salinity at End of Little Ice Age"
Data from Garcia et al., Bulletin of the American Meteorological Society, "Atmospheric Circulation Changes in the Tropical Pacific Inferred from the Voyages of the Manila Galleons in the Sixteenth - Eighteenth Centuries"

What's New for 2001:

Data from Luterbacher et al., Climate Dynamics, "Reconstruction of Sea Level Pressure fields over the eastern North Atlantic and Europe back to 1500 "
Data from Glueck and Stockton, International Journal of Climatology, "Reconstruction of the North Atlantic Oscillation, 1429-1983 "
Data from Tudhope et al. Science, "Variability in the El Niño-Southern Oscillation Through a Glacial-Interglacial Cycle "
Global Database of Borehole Temperatures and Climate Reconstructions
Data from Robertson et al. Journal of Geophysical Research , "Hypothesized Climate Forcing Time Series for the Last 500 Years "
Data from Herbert et al. Science , "Collapse of the California Current During Glacial Maxima Linked to Climate Change on Land "
Paleotempestology Resource Center
Data from Bonnefille and Chalié Global and Planetary Change , "Pollen-inferred precipitation time-series from equatorial mountains, Africa, the last 40 kyr BP. "
Data from Pederson et al., Journal of Climate , "Hydrometeorological Reconstructions for Northeastern Mongolia Derived from Tree Rings: AD 1651-1995 "
Australian Institute of Marine Science Great Barrier Reef Coral Data
WSL-Birmensdorf Global Tree Ring Data Network
New data from the North American Plant Macrofossil Database
Data from Thompson et al., Science , "A 25,000 year tropical climate history from Bolivian ice cores "
Data from Thompson et al., Science , "Late Glacial Stage and Holocene tropical ice core records from Huascarán, Peru. "
Data from Monnin et al., Science , "Atmospheric CO2 concentrations over the last glacial termination "
Data from Blunier and Brook , Science , "Timing of millennial-scale climate change in Antarctica and Greenland during the last glacial period "
Data from Biondi et al. , Journal of Climate , "North Pacific Decadal Climate Variability Since AD 1661 "

What's New for 2000:

Data from Hughen et al, Science, "Synchronous Radiocarbon and Climate Shifts During the Last Deglaciation"
Data from Felis et al, Paleoceanography, "A coral oxygen isotope record from the northern Red Sea documenting NAO, ENSO, and North Pacific teleconnections on Middle East climate variability since the year 1750. "
Data from Mann et al. Earth Interactions, "Global Temperature Patterns in Past Centuries: An Interactive Presentation"
Data from Linsley et al., Science , "Decadal Sea Surface Temperature Variability in the Sub-Tropical South Pacific from 1726 to 1997 A.D."
Data from Urban et al., Nature , "Influence of mean climate change on climate variability from a 155-year tropical Pacific coral record."
North American Drought: A Paleo Perspective
Data from Crowley Science , "Causes of Climate Change Over the Past 1000 Years"
Data from Rittenour et al., Science , "El Niño-like Climate Teleconnections in New England During the Late Pleistocene"
Data from Indermühle et al., Geophysical Research Letters , "Atmospheric CO2 Concentration from 60 to 20 Kyr BP from the Taylor Dome Ice Core, Antarctica"
Data from Verschuren et al., Nature , "Rainfall and drought in equatorial east Africa during the past 1,100 years"
Data from Fischer et al., Science , "Ice Core Records of Atmospheric CO2 Around the Last Three Glacial Terminations"
Data from Smith et al., Nature , "Dual Modes of the Carbon Cycle Since the Last Glacial Maximum"

What's New for 1999:

Data from Flückiger et al, Science, "Variations in Atmospheric N₂O Concentration During Abrupt Climatic Changes"
Data from Indermühle et al, Nature, "Holocene Carbon-cycle Dynamics Based on CO₂ Trapped in Ice at Taylor Dome, Antarctica"
Data from Mann, Bradley, & Hughes, Geophysical Research Letters, "Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations"
A Paleo Perspective... on Global Warming
Data from Woodhouse and Overpeck, Bulletin of the American Meteorological Society , "2000 Years of Drought Variability in the Central United States"

What's New for 1998:

Data from T. Blunier et al, Nature, "Asynchrony of Antarctic and Greenland Climate Change During the Last Glacial Period"
Data from Hughen et al, Radiocarbon 39, "A New 14°C Calibration Data Set for the Last Deglaciation"
Data from Briffa, Jones, Schweingruber & Osborn, Nature, "Volcanic Eruptions & N. Hemisphere Summer Temperature"
Data from Mann, Bradley, & Hughes, Nature, "Global Six Century Temperature Patterns"
The Greenland Summit Ice Cores CD-ROM is online!
Data from Stahle, et al, Science , "The Lost Colony and Jamestown Droughts"

What's New for 1997:

Overpeck, et al, Science.
"Arctic Environmental Change of the Last 4 Centuries
The NOAA NESDIS Drought Variability WWW pages, online
Version 1.1 of Analyseries - Time Series Analysis
Report on the PAGES/Clivar Intersection
Introducing: Educational Outreach, NOAA Paleo Program
IGBP - Data Information System, WWW pages, online

What's New for 1996:

The PALE Search Engine
Documents from NOAA Paleoclimatology and PAGES are now available on the Web and via FTP
Contribution Series for paleoclimatic data
Search Engine for Paleocean Data
Education Slide Project - Two New Sets: Polar Ice Cores and Rock Varnish
Pollen Data: Mirror site in Europe at Medias France
International Tree Ring Data Bank and Display Software
Site Inventory of Latin American Pollen Database

What's New for 1995:

PaleoVu (vers. 1.1) - NOAA Paleoclimatology's browse and visualization tool for paleoclimate data is now available for Microsoft Windows and Macintosh

NOAA Paleoclimatology Program
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16 March 2005