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Papers by Francesco Pausata

Nature Communications, 2015

Sources and timing of freshwater forcing relative to hydroclimate shifts recorded in Greenland ic... more Sources and timing of freshwater forcing relative to hydroclimate shifts recorded in Greenland ice cores at the onset of Younger Dryas, ∼12,800 years ago, remain speculative. Here we show that progressive Fennoscandian Ice Sheet (FIS) melting 13,100-12,880 years ago generates a hydroclimate dipole with drier-colder conditions in Northern Europe and wetter-warmer conditions in Greenland. FIS melting culminates 12,880 years ago synchronously with the start of Greenland Stadial 1 and a large-scale hydroclimate transition lasting ∼180 years. Transient climate model simulations forced with FIS freshwater reproduce the initial hydroclimate dipole through sea-ice feedbacks in the Nordic Seas. The transition is attributed to the export of excess sea ice to the subpolar North Atlantic and a subsequent southward shift of the westerly winds. We suggest that North Atlantic hydroclimate sensitivity to FIS freshwater can explain the pace and sign of shifts recorded in Greenland at the climate transition into the Younger Dryas.

Earth and Planetary Science Letters, 2016

Geophysical Research Letters, 2015

Proceedings of the National Academy of Sciences, 2015

Large volcanic eruptions can have major impacts on global climate, affecting both atmospheric and... more Large volcanic eruptions can have major impacts on global climate, affecting both atmospheric and ocean circulation through changes in atmospheric chemical composition and optical properties. The residence time of volcanic aerosol from strong eruptions is roughly 2-3 y. Attention has consequently focused on their short-term impacts, whereas the long-term, ocean-mediated response has not been well studied. Most studies have focused on tropical eruptions; high-latitude eruptions have drawn less attention because their impacts are thought to be merely hemispheric rather than global. No study to date has investigated the long-term effects of high-latitude eruptions. Here, we use a climate model to show that large summer high-latitude eruptions in the Northern Hemisphere cause strong hemispheric cooling, which could induce an El Niño-like anomaly, in the equatorial Pacific during the first 8-9 mo after the start of the eruption. The hemispherically asymmetric cooling shifts the Intertropical Convergence Zone southward, triggering a weakening of the trade winds over the western and central equatorial Pacific that favors the development of an El Niño-like anomaly. In the model used here, the specified high-latitude eruption also leads to a strengthening of the Atlantic Meridional Overturning Circulation (AMOC) in the first 25 y after the eruption, followed by a weakening lasting at least 35 y. The long-lived changes in the AMOC strength also alter the variability of the El Niño-Southern Oscillation (ENSO).

Atmospheric Chemistry and Physics, 2015

Numerical model scenarios of future climate depict a global increase in temperatures and changing... more Numerical model scenarios of future climate depict a global increase in temperatures and changing precipitation patterns, primarily driven by increasing greenhouse gas (GHG) concentrations. Aerosol particles also play an important role by altering the Earth's radiation budget and consequently surface temperature. Here, we use the general circulation aerosol model ECHAM5-HAM, coupled to a mixed layer ocean model, to investigate the impacts of future air pollution mitigation strategies in Europe on winter atmospheric circulation over the North Atlantic. We analyse the extreme case of a maximum feasible end-of-pipe reduction of aerosols in the near future (2030), in combination with increasing GHG concentrations. Our results show a more positive North Atlantic Oscillation (NAO) mean state by 2030, together with a significant eastward shift of the southern centre of action of sea-level pressure (SLP). Moreover, we show a significantly increased blocking frequency over the western Mediterranean.

Geophysical Research Letters, 2013

1] In this study we use a global climate model to assess particulate matter (PM) variability indu... more 1] In this study we use a global climate model to assess particulate matter (PM) variability induced by the North Atlantic Oscillation (NAO) in Europe during winter and the potential impact on human health of a future shift in the NAO mean state. Our study shows that extreme NAO phases in the 1990s modulated most of the interannual variability of winter PM concentrations in several European countries. Increased PM concentrations as a result of a positive shift in the mean winter NAO of one standard deviation would lead to about 5500 additional premature deaths in Mediterranean countries, compared to the simulated average PM health impact for the year 2000. In central-northern Europe, instead, higher wind speed and increased PM removal by precipitation lead to negative PM concentration anomalies with associated health benefits. We suggest that the NAO index is a useful indicator for the role of interannual atmospheric variability on large-scale pollution-health impacts.

Climate of the Past, 2010

The early to mid-Holocene thermal optimum is a well-known feature in a wide variety of paleoclima... more The early to mid-Holocene thermal optimum is a well-known feature in a wide variety of paleoclimate archives from the Northern Hemisphere. Reconstructed summer temperature anomalies from across northern Europe show a clear maximum around 6 ka. For the marine realm, Holocene trends in sea-surface temperature reconstructions for the 5 North Atlantic and Norwegian Sea do not exhibit a consistent pattern of early to mid-Holocene warmth. Sea-surface temperature records based on alkenones and diatoms generally show the existence of a warm early to mid-Holocene optimum. In contrast, several foraminifer and radiolarian based temperature records from the North Atlantic and Norwegian Sea show a cool mid-Holocene anomaly and a trend towards warmer 10 temperatures in the late Holocene. In this paper, we revisit the foraminifer record from the Vøring Plateau in the Norwegian Sea. We also compare this record with published foraminifer based temperature reconstructions from the North Atlantic and with modelled (CCSM3) upper ocean temperatures. Model results indicate that while the seasonal summer warming of the sea-surface was stronger during the mid-Holocene, 15 sub-surface depths experienced a cooling. This hydrographic setting can explain the discrepancies between the Holocene trends exhibited by phytoplankton and zooplankton based temperature proxy records. 25 ern Hemisphere (Renssen et al., 2009). It is clear that proxy based reconstructions 2082 CPD Abstract 2083 CPD 5, Abstract for the Holocene are also published (Andersson et al., 2003; Risebrobakken et al., 2003). The foraminifer SST estimates were originally calculated using the modern 2084 CPD

Atmospheric Chemistry and Physics, 2012

Atmos. Chem. www.atmos-chem-phys.net/12/6357/2012/

Stalagmites from Indian and Chinese caves have been widely used to infer past strength of the Ind... more Stalagmites from Indian and Chinese caves have been widely used to infer past strength of the Indian and East Asian summer monsoon, as their oxygen isotopic composition (delta18O) is primarily controlled by the delta18O of precipitation. Here we show that a sudden increase in North Atlantic sea ice extent during the last glacial period cools the Northern Hemisphere, reduces precipitation

We investigate sea level pressure variability in the extratropical North Atlantic in the preindus... more We investigate sea level pressure variability in the extratropical North Atlantic in the preindustrial climate (1750 A.D.) and at the Last Glacial Maximum (LGM, 21 kyr before present) using four climate models. In general, the models exhibit a significant reduction in interannual variance of sea level pressure during the LGM compared to pre-industrial simulations and this reduction is concentrated in

Speleothems from Indian and Chinese caves have been broadly used to infer past monsoon strength, ... more Speleothems from Indian and Chinese caves have been broadly used to infer past monsoon strength, since the oxygen isotopic composition of the spelothems is primarily controlled by the oxygen composition of the precipitation. However, the d18O changes recorded by the speleothems could be due not only to a change in the strength of the monsoon but also to other causes,

Nature Geoscience, 2011

Carbonate cave deposits in India and China are assumed to record the intensity of monsoon precipi... more Carbonate cave deposits in India and China are assumed to record the intensity of monsoon precipitation, because the δ 18 O of the carbonate tracks the isotopic signature of precipitation. These records show spatially coherent variability throughout the last ice age and suggest that monsoon strength was altered during the millennial-scale climate variations known as Dansgaard-Oeschger events and during the Heinrich cooling events. Here we use a numerical climate model with an embedded oxygen-isotope model to assess what caused the shifts in the oxygen-isotope signature of precipitation during a climate perturbation designed to mimic a Heinrich event. Our simulations show that a sudden increase in North Atlantic sea-ice extent during the last glacial period leads to cooling in the Northern Hemisphere, reduced precipitation over the Indian basin and weakening of the Indian monsoon. The precipitation is isotopically heavier over India and the water vapour exported to China is isotopically enriched. Our model broadly reproduces the enrichment of δ 18 O over Northern India and East Asia evident in speleothem records during Heinrich events. We therefore conclude that changes in the δ 18 O of cave carbonates associated with Heinrich events reflect changes in the intensity of Indian rather than East Asian monsoon precipitation.

Climate of the Past Discussions, 2015

Journal articles by Francesco Pausata

PNAS, 2021

Anthropogenic climate change is currently driving environmental transformation on a scale and at ... more Anthropogenic climate change is currently driving environmental transformation on a scale and at a pace that exceeds historical records. This represents an undeniably serious challenge to existing social, political, and economic systems. Humans have successfully faced similar challenges in the past, however. The archaeological record and Earth archives offer rare opportunities to observe the complex interaction between environmental and human systems under different climate regimes and at different spatial and temporal scales. The archaeology of climate change offers opportunities to identify the factors that promoted human resilience in the past and apply the knowledge gained to the present, contributing a much-needed, long-term perspective to climate research. One of the strengths of the archaeological record is the cultural diversity it encompasses, which offers alternatives to the solutions proposed from within the Western agro-industrial complex, which might not be viable cross-culturally. While contemporary climate discourse focuses on the importance of biodiversity, we highlight the importance of cultural diversity as a source of resilience. archaeology | climate change | cultural diversity | resilience | climate science