Preprints
Filtering by Subject: Climate
Further improvement of warming-equivalent emissions calculation
Published: 2021-01-22
Subjects: Climate
GWP* was recently proposed1 as a simple metric for calculating warming-equivalent emissions by equating a change in the rate of emission of a short-lived climate pollutant (SLCP) to a pulse emission of carbon-dioxide. Other metrics aiming to account for the time-dependent impact of SLCP emissions, such as CGWP, have also been proposed2. In 2019 an improvement to GWP* was proposed by Cain et al3, [...]
The influence of orbital parameters on the North American Monsoon system during the Last Interglacial Period
Published: 2020-12-17
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Environmental Sciences, Hydrology, Oceanography and Atmospheric Sciences and Meteorology
The response of summer precipitation in the western U.S. to climate variability remains a subject of uncertainty. For example, paleoclimate records indicate the North American monsoon (NAM) was stronger and spatially more extensive during the Holocene, whereas recent modeling suggests a weakened NAM response to increasing temperatures. These illustrate diverging pictures of the NAM response to [...]
Chevrons: origin and relevance for the reconstruction of past wind regimes
Published: 2020-12-15
Subjects: Climate, Earth Sciences, Geology, Geomorphology, Meteorology, Other Life Sciences, Sedimentology, Stratigraphy
Since its first use in the late 80’s, the term chevron has been employed in numerous studies to describe large U- and V-shaped ridges found in or near shorelines worldwide. Most studies have so far focused on Bahamian chevrons that are exclusively of Late Pleistocene age, and on the supposed Holocene chevrons found in S-Madagascar and Australia. In the Bahamas, these deposits have been [...]
Differences in carbon isotope discrimination between angiosperm and gymnosperm woody plants, and their geological significance
Published: 2020-12-13
Subjects: Biogeochemistry, Climate, Geochemistry, Oceanography and Atmospheric Sciences and Meteorology, Paleobiology
For most of the Phanerozoic Eon, Earth’s woody vegetation has been dominated by C3 plants – predominantly gymnosperms - with angiosperms only emerging as the dominant plant group as CO2 declined during the Cenozoic (66 Ma onward). At present, differences in carbon isotope discrimination (Δ13C) between angiosperm and gymnosperm plants are relatively small (2–3 ‰), but an increasing body of [...]
Stalagmite carbon isotopes suggest deglacial increase in soil respiration in Western Europe driven by temperature change
Published: 2020-12-03
Subjects: Biogeochemistry, Climate, Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Speleology
The temperate region of Western Europe underwent dramatic climatic and environmental change during the last deglaciation. Much of what is known about the terrestrial ecosystem response to deglacial warming stems from pollen preserved in sediment sequences, providing information on vegetation composition. Other ecosystem processes, such as soil respiration, remain poorly constrained over past [...]
Enhanced hydrological cycle increases ocean heat uptake and moderates transient climate sensitivity
Published: 2020-11-25
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology
The large-scale moistening of the atmosphere in response to increasing greenhouse gases amplifies the existing patterns of precipitation minus evaporation (P-E) which, in turn, amplifies the spatial contrast in sea surface salinity (SSS). Through a series of CO2 doubling experiments, we demonstrate that surface salinification driven by the amplified dry conditions (P-E < 0), primarily in the [...]
A global Bayesian temperature calibration for lacustrine brGDGTs
Published: 2020-11-14
Subjects: Biogeochemistry, Climate
Despite widespread use of branched glycerol dialkyl glycerol tetraethers (brGDGTs) for paleo-temperature reconstruction, no global calibration for their application in lakes has been generated since improved analytical methods have allowed for the separation of the structural isomers. This is a substantial obstacle for the application of this tool as soil calibrations underestimate temperature [...]
ENSO Drives Child Undernutrition in the Global Tropics
Published: 2020-11-13
Subjects: Applied Statistics, Climate, Environmental Public Health, Environmental Sciences, Environmental Studies, Other Environmental Sciences, Public Health, Social and Behavioral Sciences, Sustainability
The El Nino Southern Oscillation (ENSO) is a principal component of global climate variability known to influence a host of social and economic outcomes, but its systematic effects on human health remain poorly understood. We estimate ENSO’s association with child nutrition at global scale by combining variation in ENSO intensity from 1986-2018 with children’s height and weight from 186 surveys [...]
The Emergent Influence of Anthropogenic Warming on Global Crop Yields
Published: 2020-10-30
Subjects: Atmospheric Sciences, Climate, Environmental Sciences, Social and Behavioral Sciences, Statistical Methodology
A large literature on “detection and attribution” has now demonstrated the influence of anthropogenic greenhouse gas emissions on a range of physical climate variables. Social and economic outcomes are known to be sensitive to climate change, but directly connecting observed changes to anthropogenic forcing is challenging. Here I estimate the effect of anthropogenic warming on global crop yield [...]
A data assimilation approach to last millennium temperature field reconstruction using a limited high-sensitivity proxy network
Published: 2020-10-23
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Paleoclimate field reconstructions using data assimilation commonly employ large proxy networks, which are often composed of records that have a complex range of sensitivities to the target climate field. This can introduce biases into reconstructions or decrease overall skill. Smaller networks of highly-sensitive proxies provide an alternative, but have not been extensively used for assimilation [...]
Leaf trait plasticity alters competitive ability and functioning of simulated tropical trees in response to elevated carbon dioxide
Published: 2020-10-21
Subjects: Biogeochemistry, Climate, Terrestrial and Aquatic Ecology
The response of tropical ecosystems to elevated carbon dioxide (CO$_2$) remains a critical uncertainty in projections of future climate. Here we investigate how leaf trait plasticity in response to elevated CO$_2$ alters projections of tropical forest competitive dynamics and functioning. We use vegetation demographic model simulations to quantify how plasticity in leaf mass per area and leaf [...]
Identifying and correcting the World War 2 warm anomaly in sea surface temperature measurements
Published: 2020-08-21
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Most foregoing estimates of historical sea surface temperature (SST) feature warmer global-average SSTs during World War 2 well in excess of climate-model predictions. This warm anomaly, referred to as the WW2WA, was hypothesized to arise from incomplete corrections of biases associated with rapid changes in measurement instruments and protocols. Using linear mixed-effects methods we confirm [...]
Correcting 19th and 20th century sea surface temperatures improves simulations of Atlantic hurricane activity
Published: 2020-08-21
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Changes in the statistics of North Atlantic hurricanes are known to depend upon the pattern of tropical sea surface temperatures (SSTs). Dynamical and statistical models are key tools to predict future hurricane activity, with our confidence in this application rooted in the models’ ability to skillfully reproduce hurricane variations over the past 30-40 years, when satellite data allows [...]
Changes in temperature and rainfall extremes across East Asia in the CMIP5 ensemble
Published: 2020-07-22
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
We analyze annual extremes of daily maximum and minimum surface air temperature and of daily rainfall in East Asia and the Korean peninsula. This study made intensive use of the simulation data available from the CMIP5 (Coupled Model intercomparison Project Phase 5) multimodels in historical and future experiments up to year 2100, employing three different radiative forcings: RCP2.6, RCP4.5, [...]
Alkenone isotopes show evidence of active carbon concentrating mechanisms in coccolithophores as aqueous carbon dioxide concentrations fall below 7 µmolL-1
Published: 2020-07-15
Subjects: Biogeochemistry, Climate, Earth Sciences, Geochemistry, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Coccolithophores and other haptophyte algae acquire the carbon required for metabolic processes from the water in which they live. Whether carbon is actively moved across the cell membrane via a carbon concentrating mechanism, or passively through diffusion, is important for haptophyte biochemistry. The possible utilisation of carbon concentrating mechanisms also has the potential to overprint [...]