Atmospheric CO2 and O2 During the Phanerozoic: Tools, Patterns, and Impacts

Royer, Dana L.

doi:10.1016/b978-0-08-095975-7.01311-5

Cited by 85 publications

(97 citation statements)

References 272 publications

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“…These statistical characteristics of the dataset, rather than deterioration of information quality with age, may explain the weak increase in sample CV with age. Error analysis suggests that the maximum uncertainty associated with CO 2 concentration proxies is~17-50% for foraminifera at an atmospheric CO 2 concentration of 1500 ppmv, less at lower CO 2 concentrations, and less for other proxies such as boron [40] (Figure 3, p. 255). The uncertainties in proxies of atmospheric CO 2 concentration (2σ, 96% confidence limits) are generally <200 ppmv [52] ( Figure 1, p. 380).…”

Section: Co 2 Proxiesmentioning

confidence: 99%

“…These pilot studies employed the original T [38] and atmospheric CO 2 concentration [19] proxy databases. Pilot studies also included temperatures adjusted for the pH of seawater versus atmospheric CO 2 concentration across the Phanerozoic [19], temperatures projected using the carbon-cycle model GEOCARB-III versus CO 2 concentration [19], and both detrended and non-detrended temperature records computed from δ 18 O data drawn from the older proxy database [24,38] versus both the old [19] and updated [40] atmospheric CO 2 concentration databases.…”

Section: Pilot Studiesmentioning

confidence: 99%

“…Proxies of atmospheric CO 2 (n = 831) were obtained from the expanded and updated CO 2 database compiled by Royer [40] and composed of measurements from six sources, predominantly δ 13 C (61%) consisting of paleosols (39%), plankton (foraminiferans, 20%) and liverworts (2%). The balance of CO 2 proxy data are from measurements of stomatal indices/ratios (29%), marine boron (10%) and sodium carbonates (<1%).…”

Section: Co 2 Proxiesmentioning

confidence: 99%

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The Relationship between Atmospheric Carbon Dioxide Concentration and Global Temperature for the Last 425 Million Years

Davis

2017

Climate

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Assessing human impacts on climate and biodiversity requires an understanding of the relationship between the concentration of carbon dioxide (CO 2 ) in the Earth's atmosphere and global temperature (T). Here I explore this relationship empirically using comprehensive, recently-compiled databases of stable-isotope proxies from the Phanerozoic Eon (~540 to 0 years before the present) and through complementary modeling using the atmospheric absorption/transmittance code MODTRAN. Atmospheric CO 2 concentration is correlated weakly but negatively with linearly-detrended T proxies over the last 425 million years. Of 68 correlation coefficients (half non-parametric) between CO 2 and T proxies encompassing all known major Phanerozoic climate transitions, 77.9% are non-discernible (p > 0.05) and 60.0% of discernible correlations are negative. Marginal radiative forcing (∆RF CO2 ), the change in forcing at the top of the troposphere associated with a unit increase in atmospheric CO 2 concentration, was computed using MODTRAN. The correlation between ∆RF CO2 and linearly-detrended T across the Phanerozoic Eon is positive and discernible, but only 2.6% of variance in T is attributable to variance in ∆RF CO2 . Of 68 correlation coefficients (half non-parametric) between ∆RF CO2 and T proxies encompassing all known major Phanerozoic climate transitions, 75.0% are non-discernible and 41.2% of discernible correlations are negative. Spectral analysis, autoand cross-correlation show that proxies for T, atmospheric CO 2 concentration and ∆RF CO2 oscillate across the Phanerozoic, and cycles of CO 2 and ∆RF CO2 are antiphasic. A prominent 15 million-year CO 2 cycle coincides closely with identified mass extinctions of the past, suggesting a pressing need for research on the relationship between CO 2 , biodiversity extinction, and related carbon policies. This study demonstrates that changes in atmospheric CO 2 concentration did not cause temperature change in the ancient climate.

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Section: Co 2 Proxiesmentioning

confidence: 99%

Section: Pilot Studiesmentioning

confidence: 99%

Section: Co 2 Proxiesmentioning

confidence: 99%

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The Relationship between Atmospheric Carbon Dioxide Concentration and Global Temperature for the Last 425 Million Years

Davis

2017

Climate

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“…At developmental time scales, there are strong species-specific differences in sensitivity, including cases of apparent insensitivity (Reid et al, 2003;Tricker et al, 2005;Haworth et al, 2015), as well as nonlinearities in the response over both developmental and evolutionary time scales . This has been especially problematic in attempts to use the change in D in leaf fossils, alone, as a proxy for change in global mean c a (Royer, 2014). A detailed theoretical framework for modeling the response of D to c a has been proposed that uses principles of leaf gas-exchange optimization (Konrad et al, 2008), but this awaits broader implementation and validation.…”

Section: Stomatal Size Density and Conductance Through Deep Timementioning

confidence: 99%

Stomatal Function across Temporal and Spatial Scales: Deep-Time Trends, Land-Atmosphere Coupling and Global Models

et al. 2017

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“…A remaining problem is to understand what combination of radiative forcing and climate sensitivity gave rise to these very elevated temperatures in the first place (Caballero and Huber, 2013). While early Cenozoic CO 2 concentrations are understood to have been higher than modern ones (Royer, 2014), achieving a good match with reconstructed temperatures using CO 2 alone as the warming agent requires extremely high model CO 2 levels (Lunt et al, 2012), exceeding even the rather loose constraints imposed by the CO 2 proxies.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric circulation and hydroclimate impacts of alternative warming scenarios for the Eocene

Carlson

Caballero

2017

Clim. Past

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Abstract. Recent work in modelling the warm climates of the early Eocene shows that it is possible to obtain a reasonable global match between model surface temperature and proxy reconstructions, but only by using extremely high atmospheric CO 2 concentrations or more modest CO 2 levels complemented by a reduction in global cloud albedo. Understanding the mix of radiative forcing that gave rise to Eocene warmth has important implications for constraining Earth's climate sensitivity, but progress in this direction is hampered by the lack of direct proxy constraints on cloud properties. Here, we explore the potential for distinguishing among different radiative forcing scenarios via their impact on regional climate changes. We do this by comparing climate model simulations of two end-member scenarios: one in which the climate is warmed entirely by CO 2 (which we refer to as the greenhouse gas (GHG) scenario) and another in which it is warmed entirely by reduced cloud albedo (which we refer to as the "low CO 2 -thin clouds" or LCTC scenario) . The two simulations have an almost identical global-mean surface temperature and equator-to-pole temperature difference, but the LCTC scenario has ∼ 11 % greater global-mean precipitation than the GHG scenario. The LCTC scenario also has cooler midlatitude continents and warmer oceans than the GHG scenario and a tropical climate which is significantly more El Niño-like. Extremely high warm-season temperatures in the subtropics are mitigated in the LCTC scenario, while cool-season temperatures are lower at all latitudes. These changes appear large enough to motivate further, more detailed study using other climate models and a more realistic set of modelling assumptions.

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Atmospheric CO2 and O2 During the Phanerozoic: Tools, Patterns, and Impacts

Cited by 85 publications

References 272 publications

The Relationship between Atmospheric Carbon Dioxide Concentration and Global Temperature for the Last 425 Million Years

The Relationship between Atmospheric Carbon Dioxide Concentration and Global Temperature for the Last 425 Million Years

Stomatal Function across Temporal and Spatial Scales: Deep-Time Trends, Land-Atmosphere Coupling and Global Models

Atmospheric circulation and hydroclimate impacts of alternative warming scenarios for the Eocene

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