Solar modulation of Little Ice Age climate in the tropical Andes

Polissar, P. J.; Abbott, Mark B.; Wolfe, Alexander P.; Bezada, Maximiliano; Rull, Valentı́; Bradley, Raymond S.

doi:10.1073/pnas.0603118103

Cited by 103 publications

(107 citation statements)

References 51 publications

(38 reference statements)

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“…3). In the Caribbean the record from Punta Laguna (21), northeast Yucatan, also shows a signal that follows solar activity, with higher moisture during solar minima (6) (Fig. 3).…”

Section: Discussionmentioning

confidence: 96%

“…Low-latitude cooling during the LIA is evident from tropical glacier advances (5,6), and reduced sea-surface temperatures in the Caribbean (7)(8)(9). Dry LIA conditions in the Caribbean are relatively well documented and explained by a change in the position of the Intertropical Convergence Zone (ITCZ) (10,11), but little is known about the impact that this climatic event had on the lowland tropical ecosystems of the Americas.…”

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confidence: 99%

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Tracing the effects of the Little Ice Age in the tropical lowlands of eastern Mesoamerica

Lozano‐García¹,

Caballero

Ortega

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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The causes of late-Holocene centennial to millennial scale climatic variability and the impact that such variability had on tropical ecosystems are still poorly understood. Here, we present a highresolution, multiproxy record from lowland eastern Mesoamerica, studied to reconstruct climate and vegetation history during the last 2,000 years, in particular to evaluate the response of tropical vegetation to the cooling event of the Little Ice Age (LIA). Our data provide evidence that the densest tropical forest cover and the deepest lake of the last two millennia were coeval with the LIA, with two deep lake phases that follow the Spö rer and Maunder minima in solar activity. The high tropical pollen accumulation rates limit LIA's winter cooling to a maximum of 2°C. Tropical vegetation expansion during the LIA is best explained by a reduction in the extent of the dry season as a consequence of increased meridional flow leading to higher winter precipitation. These results highlight the importance of seasonal responses to climatic variability, a factor that could be of relevance when evaluating the impact of recent climate change.climate variability ͉ Late Holocene ͉ Mexico ͉ seasonality ͉ tropical ecosystems T he Little Ice Age (LIA) (1350-1850 A.D.) has been identified as one of the most important climatic oscillations of the late Holocene and the last of several centennial to millennial scale Holocene cooling events centered over the North Atlantic (1-4). Low-latitude cooling during the LIA is evident from tropical glacier advances (5, 6), and reduced sea-surface temperatures in the Caribbean (7-9). Dry LIA conditions in the Caribbean are relatively well documented and explained by a change in the position of the Intertropical Convergence Zone (ITCZ) (10, 11), but little is known about the impact that this climatic event had on the lowland tropical ecosystems of the Americas. Lago Verde, near the coast of the Gulf of Mexico (Fig. 1), is a highly sensitive record of recent climate change (12,13) where the response of the tropical vegetation and the lake system to the LIA cooling can be clearly traced, without any significant human impact. Multiproxy data from this lake show that in this tropical region the LIA is recorded by the deepest lake level and the densest forest cover of the last two millennia. In this article, we present arguments evaluating the role of solar forcing as an important element explaining climatic variability in the tropics and the North Atlantic region. We also discuss the role of regional moisture balance as a condition for the expression of regional precipitation trends, and, finally, we present an argument about the importance that changes in the seasonality of precipitation can have over the Gulf of Mexico coastal region, mitigating the dry LIA trend recorded in some areas of the Caribbean. Study SiteThis study is based mainly on pollen, charcoal particles, and diatom analyses on the sediment record from Lago Verde, a small, closed-basin lake at 200 m above sea level, on the outskirts of ...

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“…3). In the Caribbean the record from Punta Laguna (21), northeast Yucatan, also shows a signal that follows solar activity, with higher moisture during solar minima (6) (Fig. 3).…”

Section: Discussionmentioning

confidence: 96%

mentioning

confidence: 99%

Tracing the effects of the Little Ice Age in the tropical lowlands of eastern Mesoamerica

Lozano‐García¹,

Caballero

Ortega

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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“…• Polissar et al (2006) used two 1,500-yr-long sediment cores from Lakes Mucubaji and Blanca, Venezuela, to reconstruct proxy records for glacier activity, temperature, and moisture balance in that part of the tropical Andes (the Cordillera de Merida). Techniques used included measurement for biogenic silica, magnetic susceptibility, total organic carbon (TOC), total nitrogen (TN), δ 13 CTOC, δ 15 NTN, and C/N.…”

Section: South Americamentioning

confidence: 99%

Observations: Cryosphere

2014

Climate Change 2013 – The Physical Science Basis

142

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“…In addition, high altitude tropical regions are very sensitive to relatively small changes in radiative forcing. Thus, solar activity has also exerted a strong influence at different temporal scales, playing a key role at century-scale tropical climate variability during the Late Holocene modulating both precipitation and temperature (Gray et al, 2010;Polissar et al, 2006). …”

Section: Climate Forcing Of the Laminae Formationmentioning

confidence: 99%

Biogeochemical processes controlling oxygen and carbon isotopes of diatom silica in Late Glacial to Holocene lacustrine rhythmites

Hernández

Bao

Giralt

et al. 2011

Palaeogeography, Palaeoclimatology, Palaeoecology

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Biogeochemical cycles and sedimentary records in lakes are related to climate controls on hydrology and catchment processes. Changes in the isotopic composition of the diatom frustules (δ 18 O diatom and δ 13 C diatom ) in lacustrine sediments can be used to reconstruct palaeoclimatic and palaeoenvironmental changes. The Lago Chungará (Andean Altiplano, 18°15′S, 69°10′W, 4520 masl) diatomaceous laminated sediments are made up of white and green multiannual rhythmites. White laminae were formed during short-term diatom superblooms, and are composed almost exclusively of large-sized Cyclostephanos andinus. These diatoms bloom during mixing events when recycled nutrients from the bottom waters are brought to the surface and/or when nutrients are introduced from the catchment during periods of strong runoff. Conversely, the green laminae are thought to have been deposited over several years and are composed of a mixture of diatoms (mainly smaller valves of C. andinus and Discostella stelligera) and organic matter. These green laminae reflect the lake's hydrological recovery from a status favouring the diatom super-blooms (white laminae) towards baseline conditions. δ 18 O diatom and δ 13 C diatom from 11,990 to 11,530 cal years BP allow us to reconstruct shifts in the precipitation/evaporation ratio and changes in the lake water dissolved carbon concentration, respectively. δ 18 O diatom values indicate that white laminae formation occurred mainly during low lake level stages, whereas green laminae formation generally occurred during high lake level stages. The isotope and chronostratigraphical data together suggest that white laminae deposition is caused by extraordinary environmental events. El Niño-Southern Oscillation and changes in solar activity are the most likely climate forcing mechanisms that could trigger such events, favouring hydrological changes at interannual-to-decadal scale. This study demonstrates the potential for laminated lake sediments to document extreme pluriannual events.

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Solar modulation of Little Ice Age climate in the tropical Andes

Cited by 103 publications

References 51 publications

Tracing the effects of the Little Ice Age in the tropical lowlands of eastern Mesoamerica

Tracing the effects of the Little Ice Age in the tropical lowlands of eastern Mesoamerica

Observations: Cryosphere

Biogeochemical processes controlling oxygen and carbon isotopes of diatom silica in Late Glacial to Holocene lacustrine rhythmites

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