Annual Average Surface Temperature Research Articles

Equilibrium climate sensitivity in light of observations over the warming hiatus

A key uncertainty in projecting future climate change is the magnitude of equilibrium climate sensitivity (ECS), that is, the eventual increase in global annual average surface temperature in response to a doubling of atmospheric CO2 concentration. The lower bound of the likely range for ECS given in the IPCC Fifth Assessment Report (AR5; refs 1,2) was revised downwards to 1.5 degrees C, from 2 degrees C in its previous report(3), mainly as an effect of considering observations over the warming hiatus-the period of slowdown of global average temperature increase since the early 2000s. Here we analyse how estimates of ECS change as observations accumulate over time and estimate the contribution of potential causes to the hiatus. We find that including observations over the hiatus reduces the most likely value for ECS from 2.8 degrees C to 2.5 degrees C, but that the lower bound of the 90% range remains stable around 2 degrees C. We also find that the hiatus is primarily attributable to El Nino/Southern Oscillation-related variability and reduced solar forcing.

The global warming hiatus—a natural product of interactions of a secular warming trend and a multi-decadal oscillation

The globally-averaged annual combined land and ocean surface temperature (GST) anomaly change features a slowdown in the rate of global warming in the mid-twentieth century and the beginning of the twenty-first century. Here, it is shown that the hiatus in the rate of global warming typically occurs when the internally generated cooling associated with the cool phase of the multi-decadal variability overcomes the secular warming from human-induced forcing. We provide compelling evidence that the global warming hiatus is a natural product of the interplays between a secular warming tendency due in a large part to the buildup of anthropogenic greenhouse gas concentrations, in particular CO2 concentration, and internally generated cooling by a cool phase of a quasi-60-year oscillatory variability that is closely associated with the Atlantic multi-decadal oscillation (AMO) and the Pacific decadal oscillation (PDO). We further illuminate that the AMO can be considered as a useful indicator and the PDO can be implicated as a harbinger of variations in global annual average surface temperature on multi-decadal timescales. Our results suggest that the recent observed hiatus in the rate of global warming will very likely extend for several more years due to the cooling phase of the quasi-60-year oscillatory variability superimposed on the secular warming trend.

Assessment of CMIP5 Simulations for China Annual Average Surface Temperature and Its Comparison with CMIP3 Simulations

Assessment of CMIP5 Simulations for China Annual Average Surface Temperature and Its Comparison with CMIP3 Simulations

Thermal model for analysis of Mars infrared mapping

AbstractThe KRC numerical thermal model has been used in the analysis of observations from virtually all Mars missions with infrared sensors and for the selection of virtually all Mars' landing sites. It uses a physics‐based one‐layer atmosphere gray at solar and thermal wavelengths to determine the radiative effect of a dusty atmosphere. One gas component may condense to form a seasonal polar cap and affect the global surface pressure. The atmosphere may be omitted entirely to model airless bodies. KRC uses layers that become thicker geometrically with depth and it uses repeated time step doubling. The surface may be homogeneous or have two zones of material properties, each zone may have temperature‐dependent thermal conductivity and specific heat. Surface slopes or depressions are modeled to first order. Here KRC is described in detail and used to compute globally the annual average surface temperature accounting for albedo, thermal inertia, elevation, slope at 3 km resolution, and zonal climate. Comparisons with three other thermal models are discussed. The model is available for general use.

Estimating the power of Mars’ greenhouse effect

Extensive modeling of Mars in conjunction with in situ observations suggests that the annual average global mean surface temperature is Ts¯∼202K. Yet its effective temperature, i.e., the temperature at which a blackbody radiates away the energy it absorbs, is Te∼208K. How can a planet with a CO2 atmosphere have a mean annual surface temperature that is actually less than its effective temperature? We use the Ames General Circulation Model explain why this is the case and point out that the correct comparison of the effective temperature is with the effective surface temperature Tse, which is the fourth root of the annual and globally averaged value of Ts4. This may seem obvious, but the distinction is often not recognized in the literature.

Empirical analysis of the influence of forest extent on annual and seasonal surface temperatures for the continental United States

AbstractAimBecause of the low albedo of forests and other biophysical factors, most scenario‐based climate modelling studies indicate that removal of temperate forest will promote cooling, indicating that temperate forests are a source of heat relative to other classes of land cover. Our objective was to test the hypothesis that US temperate forests reduce surface temperatures.LocationThe continental United States.MethodsOrdinary least squares regression was used to develop relationships between forest extent and surface temperature. Forest extent was derived from the 900 m2 2001 National Land Cover Database (NLCD 2001) and surface temperature data were from the MODIS 1 km2 8‐day composite (MYD11A2). Forest–surface temperature relationships were developed for winter, spring, summer, autumn and annually using 5 years of MODIS land surface temperature data (2007–11) across six spatial scales (1, 4, 9, 16, 25 and 36 km2). Regression models controlled for the effects of elevation, aspect and latitude (by constraining the regressions within a 1° range).ResultsWe did not find any significant positive slopes in regressions of average annual surface temperatures versus the proportion of forest, indicating that forests are not a source of heat relative to other types of land cover. We found that surface temperatures declined as the proportion of forest increased for spring, summer, autumn and annually. The forest–surface temperature relationship was also scale dependent in that spatially extensive forests produced cooler surface temperatures than forests that were dominant only locally.Main conclusionsOur results are not consistent with most scenario‐based climate modelling studies. Because of their warming potential, the value of temperate afforestation as a potential climate change mitigation strategy is unclear. Our results indicate that temperate afforestation is a climate change mitigation strategy that should be implemented to promote spatially extensive forests.

Does Global Warming Increase Establishment Rates of Invasive Alien Species? A Centurial Time Series Analysis

BackgroundThe establishment rate of invasive alien insect species has been increasing worldwide during the past century. This trend has been widely attributed to increased rates of international trade and associated species introductions, but rarely linked to environmental change. To better understand and manage the bioinvasion process, it is crucial to understand the relationship between global warming and establishment rate of invasive alien species, especially for poikilothermic invaders such as insects.Methodology/Principal FindingsWe present data that demonstrate a significant positive relationship between the change in average annual surface air temperature and the establishment rate of invasive alien insects in mainland China during 1900–2005. This relationship was modeled by regression analysis, and indicated that a 1°C increase in average annual surface temperature in mainland China was associated with an increase in the establishment rate of invasive alien insects of about 0.5 species year−1. The relationship between rising surface air temperature and increasing establishment rate remained significant even after accounting for increases in international trade during the period 1950–2005. Moreover, similar relationships were detected using additional data from the United Kingdom and the contiguous United States.Conclusions/SignificanceThese findings suggest that the perceived increase in establishments of invasive alien insects can be explained only in part by an increase in introduction rate or propagule pressure. Besides increasing propagule pressure, global warming is another driver that could favor worldwide bioinvasions. Our study highlights the need to consider global warming when designing strategies and policies to deal with bioinvasions.

Valuing the non-CO2 climate impacts of aviation

The non-CO2 climate impact of aviation (NOx and contrails) is assessed and emissions weighting factors (EWFs) i.e., the factor by which aviation CO2 emissions should be multiplied to get the CO2-equivalent emissions for annual fleet average conditions are estimated. The EWFs are estimated using two economic metrics. One is based on the relative damage cost between non-CO2 forcers and CO2. The other is based on the cost-effective valuation between the non-CO2 forcers and CO2 given an upper ceiling on the global annual average surface temperature (set at 2 K above pre-industrial levels). We also estimate EWFs using three physical metrics, Global Warming Potential (GWP), Global Temperature change Potential (GTP) and Sustained GTP (SGTP) and compare our results with the economics based metrics. Given best estimates on the forcing contributions from CO2, contrails and NOx from aviation and by using a discount rate of 3%/year, the RDC based metric gives an EWF equal to 1.4 (slightly higher than EWFs based on GWP and SGTP using a 100 year time horizon). EWF using the cost-effective approach depends on the time that remains before stabilization occurs. It is roughly equal to unity until a few years before the temperature reaches its ceiling, and approximately 2 when stabilization has taken place. EWFs based on GTP resemble those based on CETO when the time left to when stabilization occurs is sufficiently large. Once stabilization has occurred CETO values resemble RDC based values. If aviation-induced cirrus clouds are included, uncertainties increase and the EWFs for GWP, SGTP and RDC based metrics end up in the range 1.3–2.9, while EWFs for GTP and CETO remain close to unity in the near term.

Simulation of spatiotemporal dynamics of water fluxes in Germany under climate change

AbstractIn most of Europe, an increase in average annual surface temperature of 0·8 °C is observed, and a further increase is projected. Precipitation tends to increase in northern Europe and decrease in southern Europe, with variable trends in central Europe. The climate scenarios for Germany suggest an increase in precipitation in western Germany and a decrease in eastern Germany, and a shift of precipitation from summer to winter. When investigating the effects of climate change, impacts on water resources are among the main concerns. In this study, the first German‐wide impact assessment of water fluxes dynamics under climate change is presented in a spatially and temporally distributed manner using the state‐of‐the‐art regional climate model, Statistical Regional (STAR) model and the semi‐distributed process‐based eco‐hydrological model, soil and water integrated model (SWIM). All large river basins in Germany (lower Rhine, upper Danube, Elbe, Weser and Ems) are included. A special focus of the study was on data availability, homogeneity of data sets, related uncertainty propagation in the model results and scenario‐related uncertainty. After the model calibration and validation (efficiency from 0·6 to 0·9 in 80% of cases) the water flow components were simulated at the hydrotope level, and the spatial distributions were compared with those in the Hydrological Atlas of Germany. The actual evapotransipration is likely to increase in most parts of Germany, while total runoff generation may decrease in south and east regions. The results for the second scenario period 2051–2060 show that water discharge in all six rivers would be 8–30% lower in summer and autumn compared with the reference period, and the strongest decline is expected for the Saale, Danube and Neckar. Higher winter flow is expected in all of these rivers, and the increase is most significant for the Ems (about 18%). However, the uncertainty of impacts, especially in winter and for high water flows, remains high. Copyright © 2010 John Wiley & Sons, Ltd.

An experimental study on the cooling mechanism of a shading board in permafrost engineering

Shading boards (SB) were tested on an embankment slope as one of the measures for actively cooling permafrost in roadbed engineering along the Qinghai-Tibet Highway on the Tibet Plateau, China. A series of tests, evaluating the cooling mechanism of SBs, also were conducted in the laboratory that showed that the SB cooled the permafrost by significantly reducing the input of solar radiation onto the side slope surfaces. In these laboratory tests, the radiation intensity was lowered by 85.5%. In addition, the enhanced air convection between the SB and the slope surface removed the heat produced by the secondary radiation from the back side of the board, as well as heat released from the soil. Laboratory tests indicate that the temperature on the slope surface lowered in more degree with the SB can be explained by the “stack effect” triggered between the SB and the slope surface. The accelerated air flow under the SB brings the temperature of the slope surface to ambient air temperature. There was an optimal height of 15 cm for the SB, where the air flow reached its maximum amount and velocity, which means that, in practice, the installed height of the SB should be taken into account. Also, the free flow of the air under the SB should be assured by leaving the space between the SB and the protected surface unblocked. Practical applications of the SB along the Qinghai-Tibet Highway from November 2003 to November 2004 showed that the SB could reduce the annual average surface temperature of the entire embankment side slope by about 3.2 °C compared with the unshaded embankment slope. The maximum reduction was 4 °C. The annual average slope surface temperature under the SB was about 1.5 °C lower than the nearby natural ground surface.

STATE OF THE CLIMATE IN 2004

Abstract From a global perspective, the annual average surface temperature in 2004 was the fourth highest value observed since regular instrumental records began in 1880. Global surface air temperatures in 2004 were 0.44°C (0.79°F) above the 1961–90 mean, according to both the U.S. and U.K. archives. Observations of the global annual mean temperature in 2004 from the combined lower and middle troposphere was 0.38°C (0.68°F)—the fourth warmest year in the 47-yr archive of worldwide radiosonde observations, and the ninth warmest year out of the past 26 based on satellite measurements. The average precipitation anomaly over global land areas in 2004 was 10.7 mm above average, which was ∼1% above the 1961–90 mean, and the first year since 2000 that the global mean value was wetter than average. Northern Hemisphere sea ice extent was the third lowest on record for the year, dating back to 1973. The annual snow cover extent over Northern Hemisphere land areas was 25.1 million km2, which was the 25th most extens...

An abrupt climate event in a coupled ocean-atmosphere simulation without external forcing.

Temperature reconstructions from the North Atlantic region indicate frequent abrupt and severe climate fluctuations during the last glacial and Holocene periods. The driving forces for these events are unclear and coupled atmosphere-ocean models of global circulation have only simulated such events by inserting large amounts of fresh water into the northern North Atlantic Ocean. Here we report a drastic cooling event in a 15,000-yr simulation of global circulation with present-day climate conditions without the use of such external forcing. In our simulation, the annual average surface temperature near southern Greenland spontaneously fell 6-10 standard deviations below its mean value for a period of 30-40 yr. The event was triggered by a persistent northwesterly wind that transported large amounts of buoyant cold and fresh water into the northern North Atlantic Ocean. Oceanic convection shut down in response to this flow, concentrating the entire cooling of the northern North Atlantic by the colder atmosphere in the uppermost ocean layer. Given the similarity between our simulation and observed records of rapid cooling events, our results indicate that internal atmospheric variability alone could have generated the extreme climate disruptions in this region.

Surface air temperature and its changes over the past 150 years

We review the surface air temperature record of the past 150 years, considering the homogeneity of the basic data and the standard errors of estimation of the average hemispheric and global estimates. We present global fields of surface temperature change over the two 20‐year periods of greatest warming this century, 1925–1944 and 1978–1997. Over these periods, global temperatures rose by 0.37° and 0.32°C, respectively. The twentieth‐century warming has been accompanied by a decrease in those areas of the world affected by exceptionally cool temperatures and to a lesser extent by increases in areas affected by exceptionally warm temperatures. In recent decades there have been much greater increases in night minimum temperatures than in day maximum temperatures, so that over 1950–1993 the diurnal temperature range has decreased by 0.08°C per decade. We discuss the recent divergence of surface and satellite temperature measurements of the lower troposphere and consider the last 150 years in the context of the last millennium. We then provide a globally complete absolute surface air temperature climatology on a 1° × 1° grid. This is primarily based on data for 1961–1990. Extensive interpolation had to be undertaken over both polar regions and in a few other regions where basic data are scarce, but we believe the climatology is the most consistent and reliable of absolute surface air temperature conditions over the world. The climatology indicates that the annual average surface temperature of the world is 14.0°C (14.6°C in the Northern Hemisphere (NH) and 13.4°C for the Southern Hemisphere). The annual cycle of global mean temperatures follows that of the land‐dominated NH, with a maximum in July of 15.9°C and a minimum in January of 12.2°C.

Isotope geochemistry of Upper Permian early diagenetic calcite concretions: Implications for Late Permian waters and surface temperatures in continental Gondwana

This paper presents comprehensive geochemical and isotopic studies on calcite concretions from Upper Permian freshwater continental deposits that were laid down at ≈55°S in the interior of southern Gondwana. The shales hosting the concretions are partially bioturbated and calcareous. The concretions are predominantly spheroidal and contain abundant septarian cracks. The maximum content of cement carbonate in concretion matrix varies from 65% at the centre to 15% at the edges. Ostracod remains are exclusively preserved within the concretions. Septarian calcite occurs in dull and bright bands, with three distinct generations of vein-fills: brown, euhedral calcite with saw-tooth habit; coarse fibrous white calcite, and minor fibrous white calcite with sutured termination at the centre of the veins. Early-formed cement both in concretions and septarian veins is magnesium-rich whereas, later-formed carbonates are pure calcite. Carbon- and oxygen-isotope ratios (PDB) of the carbonates are as follows: host shales, ∂ 13 C = −4.363 to 0.777‰ , ∂ 18 O = −12.732 to −17.118‰ ; concretion cements, ∂ 13 C = +0.256 to −5.378‰ , ∂ 18 O = −9.882 to −9.336‰ ; and vein-fills, ∂ 13 C = −7.053 to +1.094‰ , ∂ 18 O = −8.280 to −18.241‰ . 13 C and 18 O ratios are depleted from the centre of concretions to the periphery, as well as from the centre of veins to the tip. Near-surface cementation as suggested by textural evidence and maximum burial temperatures of 50–70°C established from organic matter and clay mineral composition allow independent estimates of surface palaeotemperatures from 18 O ratios. ∂ 18 O in the range of −12.636‰ to −8.989 SMOW is derived for the meteoric palaeowaters, from which average annual surface temperatures of 5–8°C is inferred. ∂ 18 O of early-formed cements also yields a mean annual surface temperature of 2–6°C. Considering the continentality of the palaeolatitudes of northern Malawi during the Late Permian, we contend that mean annual surface palaeotemperatures may have been as high as 10°C, similar to those found in modern continental temperate climates. This is the first independent palaeotemperature data from the interiors of southern Gondwana.

Records of Late Permian Surface Temperatures in Continental Gondwana in Isotope Geochemistry of Upper Permian Early Diagenetic Calcite Concretions: ABSTRACT

We present geochemical and isotopic evidence of paleotemperatures from freshwater continental deposits from 55[degrees]S in interior southern Gondwana. Lacustrine shales host spheroidal concretions with abundant septarian cracks. Cement carbonate varies from 65% at the centre to 15% at the edges. Cistraccide remains are preserved. Septarian calcite occurs in dull and bright bands, with three distinct generations of vein-fills. Early-formed cement both in concretions and septarian veins is magnesium-rich whereas, later-formed carbonates are pure calcite. Carbon- and oxygen-isotope ratios (PDB) are: host shales, [delta][sup 13]C= -4.36 to o.77[per thousand], [delta][sup 18]O= -12.73 to -17.12[per thousand]; concretion cements, [delta][sup 13]C=+0.26 to [delta][sup 18]O= -9.34[per thousand]; and vein-fills, [delta][sup 13]C= -7.05 to +1.09[per thousand], [delta][sup 18]O= -8.28 to -18.24[per thousand]. 13C and 18O ratios are depleted from the center of concretions to the periphery, as well as from the centre of veins to the tip. Near-surface cementation is suggested by textural evidence. [delta]18O in the range of -12.636[per thousand] to -8.989 SMOW is calculated for the meteoric palaeowaters, from which average annual surface temperatures of 5-8[degrees]C are inferred. [delta]18O of early-formed cements also yields a mean annual surface temperature of 2-6[degrees]C. Based on continentality and palaeolatitudes of northern Malawi during the Late Permian,more » we propose that mean annual surface palaeotemperatures may have been as high as 10[degrees]C, similar to those found in modern continental temperate climates.« less

Atlantic core-top calibration of the U 37K index as a sea-surface palaeotemperature indicator

A field calibration of the UK index with sea surface temperature is discussed, through analysis of an extensive suite of surface sediments ( n = 109) from the northeastern Atlantic (2°S–75°N). Values of U 37 K are compared with sea surface temperatures for overlying waters measured at different depths and seasons, to obtain a correlation suitable for palaeotemperature reconstructions. The best fit is obtained using surface (0 m) temperatures corresponding to caloric winter and autumn months. However, the annual average, spring and summer surface temperature equations also have high correlation coefficients, and are also appropriate for climatic studies. The results further validate the general applicability of the U 37 K as a climatic proxy, because the calibration equations are valid over a wide range of surface water temperatures (0–28°C) for different algal populations and are representative of the average contribution of alkenones to sediments, as found in sediment cores.

Effects of a 2 × CO 2 climate on two large lake systems: Pyramid Lake, Nevada, and Yellowstone Lake, Wyoming

The possible effects of trace-gas induced climatic changes on Pyramid and Yellowstone Lakes are assessed using a model of lake temperature. The model is driven by 3 1 2 years of hourly meteorological data obtained directly from the output of double-CO 2 experiments (2 × CO 2) conducted with a regional climate model nested in a general circulation model. The regional atmospheric model is the climate version of the National Center for Atmospheric Research/Pennsylvania State University mesoscale model, MM4. Average annual surface temperature of Pyramid Lake for the 2 × CO 2 climate is 15.5 ± 5.4°C (±1 σ), 2.8°C higher than the control. Annual overturn of the lake ceases as a result of these higher temperatures for the 2 × CO 2 climate. Evaporation increases from 1400 mm yr −1 in the control to 1595 mm yr −1 in the 2 × CO 2 simulation, but net water supplied to the Pyramid Lake basin increases from −6 mm yr −1 in the control to +27 mm yr −1 in the 2 × CO 2 simulation due to increased precipitation. For the open water periods, the average annual surface temperature of Yellowstone Lake is 13.2 ± 5.1°C for the 2 × CO 2 climate, a temperature 1.6°C higher than the control. The annual duration of ice cover on the lake is 152 days in the 2 × CO 2 simulation, a reduction of 44 days relative to the control. Warming of the lake for the 2 × CO 2 climate is mostly confined to the near-surface. Simulated spring overturn for the 2 × CO 2 climate occurs earlier in the year and fall overturn later than in the control. Evaporation increases from 544 mm yr −1 to 600 mm yr −1 in the 2 × CO 2 simulation, but net water supplied to the Yellowstone Lake basin increases from +373 mm yr −1 in the control to +619 mm yr −1 due to increased precipitation. The effects of these climatic changes suggest possible deterioration of water quality and productivity in Pyramid Lake and possible enhancement of productivity in Yellowstone Lake.

Global warming: greenhouse gases versus aerosols

Man's activities have led to an increase in the atmospheric concentration of aerosols and the aerosol precursors as well as to an increase of greenhouse gases. A crude measure of man's global activities, which cause these increases, is the annual emission of carbon in the form of CO 2 from the burning of fossil fuels. Hence as a first approximation, the additional releases of greenhouse gases and the additional production of aerosols are assumed to be proportional to the annual carbon emissions. A simple OD-model provides an estimate of the responses of the global annual average surface temperature to the increase of greenhouse gases and of aerosols. The albedo increase is estimated under the assumption that the additional aerosol production leads to a proportional increase in available cloud condensation nuclei and that the increase of greenhouse gases leads to a proportional decrease in the infrared transmittance of the atmosphere. Both effects are of the same magnitude but of opposite sign; hence, climate modelling requires the full inclusion of aerosols.

Burial Diagenetic Geothermometer and the Classifying Characteristics of the Burial Diagenetic Zones of Tertiary Clastic Rocks in Shengli Oil Field, East China

It is very important to study burial diagenesis for reservoir assessment. During the Cenozoic Era, the studied area was a downfaulted depression basin with continuous subsidence that was filled by thick clastic sediments. Based on the petrological data from 66 wells in this basin, the present geotemperature corresponding to the occurring depth of the burial diagenetic event approximates or is equal to the initial temperature of the diagenetic event. Therefore, the initial temperature of the burial diagenetic event can be calculated by this equation: T = G(H {minus} h) + 14.5C, where T is the initial temperature of the burial diagenetic even; G is geothermal gradient; H is the shallowest depth for this diagenesis occurrence; and h is the depth of constant temperature zone. The annual average surface temperature of the studied area is 14.5C. The different burial diagenetic geothermometers calculated by the equation are as follows: 65 {plus minus} 5C for minor quartz overgrowth; 90 {plus minus} 5C for intensive quartz overgrowth; 75 {plus minus} 5C for epidote dissolution; 92 {plus minus} 5C for authigenic garnet; 95 {plus minus} 5C for late carbonate cement; 140 {plus minus} 10C for transformation from kaolinite to illite. Based on all the burialmore » diagenetic geothermometers, the burial diagenetic sequence can be divided into shallow ( 130C) zones. It is demonstrated that these zones can be used to classify and assess the reservoir rocks and source rocks.« less

Intertidal barnacles—Assessment of their use as paleo-environment indicators using Mg, Sr, [formula omitted] and [formula omitted] variations

Composite shell samples of the intertidal barnacle Tetraclita serrata Darwin from eight localities around the coast of southern Africa have been analyzed for major- and minor-element contents and carbon- and oxygen-isotope ratios. These data have been used to evaluate the temperature scales that have been developed for barnacles using MgCO 3 contents and oxygen-isotope fractionations. The temperatures of seawater calculated from the δ 18O-values were found to be within ± 1†C of the average annual surface temperature computed for the sampling sites of the barnacles and to be more reliable than temperature estimates made from MgCO 3 contents. Detailed investigation of the MgCO 3 distribution in sections of the barnacle shells showed irregular variations of this component in the profile and, in particular, a marked increase in the MgCO 3 content towards the outer rim of the shells. This is attributed to dissolution and precipitation effects occuring on the outer surfaces of the shells during their alternate exposure and submergence in the intertidal zone. The carbon-isotope values show a poor negative correlation with average annual surface temperature and the relationship is not sufficiently good to be used as a paleothermometer. The Sr contents of the samples of T. serrata were found to be constant from all sample locations on the southern African coast. Similar contents have been reported in the literature for intertidal barnacles in other parts of the world. The average Sr Ca ratio of all intertidal barnacles is ∼ 8.3 · 10 −3 The consistency of this ratio suggests that Sr contents of unaltered barnacle shells preserved in sediments can be used for estimating Sr contents of the paleo-oceans.