Modelled glacier equilibrium line altitudes during the mid-Holocene in the southern mid-latitudes
Summary: We examine the climatic forcing of glacier expansion in the mid-Holocene (MH) by evaluating modelled glacier equilibrium line altitude (ELA) and climate conditions during the MH compared with pre-industrial (PI) time in the mid-latitudes of the Southern Hemisphere. Glaciers in both analysed regions have an ELA that is 15-33m lower than the PI during the MH. We postulate that the modelled ELA changes may help to explain larger glacier extents observed in the mid-Holocene in both regions.
Clim. Past, 11, 1575-1586, doi:10.5194/cp-11-1575-2015, 2015
Transitivity of the climate–vegetation system in a warm climate
Clim. Past, 11, 1563-1574, doi:10.5194/cp-11-1563-2015, 2015
Temperature changes derived from phenological and natural evidence in South Central China from 1850 to 2008
Summary: In this paper we reconstruct the annual temperature anomalies in South Central China from 1850 to 2008, using phenodates of plants, snowfall days, and five tree-ring width chronologies. It is found that rapid warming has occurred since the 1990s, with an abrupt change around 1997, leading to unprecedented variability in warming; a cold interval dominated the 1860s, 1890s, and 1950s; warm decades occurred around 1850, 1870, and 1960; and the warmest decades were the 1990s–2000s.
Clim. Past, 11, 1553-1561, doi:10.5194/cp-11-1553-2015, 2015
Quantifying molecular oxygen isotope variations during a Heinrich stadial
Summary: Isotopes of atmospheric O2 undergo millennial-scale variations during the last glacial period, and systematically increase during Heinrich stadials. Such variations are mostly due to vegetation and water cycle processes. Our modeling approach reproduces the main observed features of Heinrich stadials in terms of climate, vegetation and rainfall. It highlights the strong role of hydrology on O2 isotopes, which can be seen as a global integrator of precipitation changes over vegetated areas.
Clim. Past, 11, 1527-1551, doi:10.5194/cp-11-1527-2015, 2015
Stratification of surface waters during the last glacial millennial climatic events: a key factor in subsurface and deep-water mass dynamics
Summary: This study reports the hydrological variations recorded at different depths of the water column SW of the Faeroe Is. during the last glacial abrupt climatic events (Heinrich events and Dansgaard-Oeschger cycles). Our combined multiproxy and high-resolution approach allows us to evidence that 1) Greenland and Heinrich stadials were characterized by strong stratification of surface waters, 2) this surface stratification seems to have played a key role in the dynamics of the underlying water masses
Clim. Past, 11, 1507-1525, doi:10.5194/cp-11-1507-2015, 2015
Abrupt climate and vegetation variability of eastern Anatolia during the last glacial
Clim. Past, 11, 1491-1505, doi:10.5194/cp-11-1491-2015, 2015
How might the North American ice sheet influence the northwestern Eurasian climate?
Summary: The present study investigates the potential impact of the North American ice sheet on the surface mass balance of the Eurasian ice sheet through changes in the past glacial atmospheric circulation. Using an atmospheric circulation model and an ice-sheet model, we show that the albedo of the American ice sheet favors the growth of the Eurasian ice sheet, whereas the topography of the American ice sheet leads to more ablation over North Eurasia, and therefore to a smaller Eurasian ice sheet.
Clim. Past, 11, 1467-1490, doi:10.5194/cp-11-1467-2015, 2015
A tree-ring perspective on temporal changes in the frequency and intensity of hydroclimatic extremes in the territory of the Czech Republic since 761 AD
Summary: A new data set of 3194 oak (Quercus spp.) ring width samples collected across the Czech Republic and covering the past 1250 years was analysed. The temporal distribution of negative and positive TRW extremes occurring is regular with no indication of clustering. Negative TRW extremes coincided with above-average March-May and June-August temperature means and below-average precipitation totals. Positive extremes coincided with higher summer precipitation, while temperatures were mostly normal.
Clim. Past, 11, 1453-1466, doi:10.5194/cp-11-1453-2015, 2015
Tropical cyclone genesis potential across palaeoclimates
Summary: Here we diagnose simulated changes in large-scale climate variables associated with the formation of tropical cyclones (i.e. hurricanes and typhoons). The cumulative potential for storm formation is pretty constant, despite the climate changes between the Last Glacial Maximum and the warm Pliocene. There are, however, coherent shifts in the relative strength of the storm regions. Little connection appears between the past behaviour in the five models studied and their future projections.
Clim. Past, 11, 1433-1451, doi:10.5194/cp-11-1433-2015, 2015
Increased aridity in southwestern Africa during the warmest periods of the last interglacial
Summary: We present a new pollen-based palaeoclimatic reconstruction covering the period between 190,000 and 24,000 years ago from a marine sediment core located off the Namibian coast. Our work identifies increased dryness during the three warmest periods of the last interglacial involving atmospheric and oceanic reorganisations in southern Africa that are linked to precession minima.
Clim. Past, 11, 1417-1431, doi:10.5194/cp-11-1417-2015, 2015
Volcanic synchronization of Dome Fuji and Dome C Antarctic deep ice cores over the past 216 kyr
Clim. Past, 11, 1395-1416, doi:10.5194/cp-11-1395-2015, 2015
Late-glacial to late-Holocene shifts in global precipitation δ18O
Summary: In this study we compile global isotope proxy records of climate changes from the last ice age to the late-Holocene preserved in cave calcite, glacial ice and groundwater aquifers. We show that global patterns of late-Pleistocene to late-Holocene precipitation isotope shifts are consistent with stronger-than-modern isotopic distillation of air masses during the last ice age, likely impacted by larger global temperature differences between the tropics and the poles.
Clim. Past, 11, 1375-1393, doi:10.5194/cp-11-1375-2015, 2015
Palaeo plant diversity in subtropical Africa – ecological assessment of a conceptual model of climate–vegetation interaction
Clim. Past, 11, 1361-1374, doi:10.5194/cp-11-1361-2015, 2015
Stability of ENSO and its tropical Pacific teleconnections over the Last Millennium
Clim. Past, 11, 1347-1360, doi:10.5194/cp-11-1347-2015, 2015
Obliquity forcing of low-latitude climate
Summary: Our study shows that the influence of obliquity (the tilt of Earth's rotational axis) can be explained through changes in the insolation gradient across the tropics. This explanation is fundamentally different from high-latitude mechanisms that were previously often inferred to explain obliquity signals in low-latitude paleoclimate records, for instance glacial fluctuations. Our study is based on state-of-the-art climate model experiments.
Clim. Past, 11, 1335-1346, doi:10.5194/cp-11-1335-2015, 2015
ENSO flavors in a tree-ring δ18O record of Tectona grandis from Indonesia
Summary: Indonesia’s climate has been linked to El Niño-Southern Oscillation (ENSO) events that often result in extensive droughts and floods over Indonesia. In this study we investigate ENSO-related signals in a tree-ring δ18O record of Javanese teak. Our results reveal a clear influence of Warm Pool El Niño events on Javanese tree-ring δ18O. These results illustrate the importance of considering ENSO flavors when interpreting palaeoclimate proxy records in the tropics.
Clim. Past, 11, 1325-1333, doi:10.5194/cp-11-1325-2015, 2015
Frequency, magnitude and character of hyperthermal events at the onset of the Early Eocene Climatic Optimum
Summary: Several episodes of global warming took place during greenhouse conditions in the early Eocene and are recorded in deep-sea sediments. The stable carbon and oxygen isotope records are used to investigate the magnitude of six of these events describing their effects on the global carbon cycle and the associated temperature response. Findings indicate that these events share a common nature and hint to the presence of multiple sources of carbon release.
Clim. Past, 11, 1313-1324, doi:10.5194/cp-11-1313-2015, 2015
Parallelisms between sea surface temperature changes in the western tropical Atlantic (Guiana Basin) and high latitude climate signals over the last 140 000 years
Summary: The alkenone sea surface temperatures in the Guiana Basin show a rapid transmission of the climate variability from arctic to tropical latitudes during the last two interglacials (MIS1 and MIS5e) and warm long interstadials (MIS5d-a). In contrast, the abrupt variability of the glacial interval does follow the North Atlantic climate but is also shaped by precessional changes. This arctic to tropical decoupling occurs when the Atlantic meridional overturning circulation is substantially reduced.
Clim. Past, 11, 1297-1311, doi:10.5194/cp-11-1297-2015, 2015
Orbital control on late Miocene climate and the North African monsoon: insight from an ensemble of sub-precessional simulations
Summary: This paper investigates the climatic response to orbital forcing through the analysis of an ensemble of simulations covering a late Miocene precession cycle. Including orbital variability in our model–data comparison reduces the mismatch between the proxy record and model output. Our results indicate that ignoring orbital variability could lead to miscorrelations in proxy reconstructions. The North African summer monsoon's sensitivity is high to orbits, moderate to paleogeography and low to CO2.
Clim. Past, 11, 1271-1295, doi:10.5194/cp-11-1271-2015, 2015
Microfossil evidence for trophic changes during the Eocene–Oligocene transition in the South Atlantic (ODP Site 1263, Walvis Ridge)
Summary: Deep-sea sediments at ODP Site 1263 (Walvis Ridge, South Atlantic) show that marine calcifying algae decreased in abundance and size at the Eocene-Oligocene boundary, when the Earth transitioned from a greenhouse to a more glaciated and cooler climate. This decreased the food supply for benthic foraminifer communities. The plankton rapidly responded to fast-changing conditions, such as seasonal nutrient availability, or to threshold-levels in pCO2, cooling and ocean circulation.
Clim. Past, 11, 1249-1270, doi:10.5194/cp-11-1249-2015, 2015