Atmospheric carbon dioxide and the long-term control of the Earth's climate

1995 ◽  
Vol 13 (7) ◽  
pp. 782-790 ◽  
Author(s):  
J. H. Carver ◽  
I. M. Vardavas
Keyword(s):  
Atmospheric Carbon Dioxide ◽  
Plate Tectonics ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
The Sun ◽  
Model Calculations ◽  
Co2 Level ◽  
Earth’S Climate ◽  
Outgassing Rate ◽  
Geologic Record

Abstract. A CO2-weathering model has been used to explore the possible evolution of the Earth's climate as the Sun steadily brightened throughout geologic time. The results of the model calculations can be described in terms of three, qualitatively different, "Megaclimates". Mega-climate 1 resulted from a period of rapid outgassing in the early Archean, with high, but declining, temperatures caused by the small weathering rates on a largely water-covered planet. Mega-climate 2 began about 3 Gyear ago as major continental land masses developed, increasing the weathering rate in the early Proterozoic and thereby depleting the atmospheric CO2 concentration. This process produced the first Precambrian glaciations about 2.3 Gyear ago. During Mega-climate 2, evolutionary biological processes increased the surface weatherability in incremental steps and plate tectonics modulated the CO2 outgassing rate with an estimated period of 150 Myear (approximately one-half the period for the formation and breakup of super continents). Throughout Mega-climate 2 the surface temperature was controlled by variations in the atmospheric CO2 level allowing transitions between glacial and non-glacial conditions. The results of the model for Mega-climate 2 are in agreement with the occurrence (and absence) of glaciations in the geologic record. Extending the model to the future suggests that CO2 control of the Earth's temperature will no longer be able to compensate for a solar flux that continues to increase. The present level of atmospheric CO2 is so small that further reduction in CO2 cannot prevent the Earth from experiencing Mega-climate 3 with steadily increasing surface temperatures caused by the continued brightening of the Sun. During Mega-climate 3, the main danger to the biosphere would come not from an increasing temperature but from a decreasing (rather than an increasing) CO2 level which could, in time, fall below 0.5 PAL, causing serious damage to the biosphere. Fortunately, the rates of change due to solar brightening are slow enough that Mega-climate 3 appears to pose no threat to the biosphere for the next 0.5-2 Gyear.

scholarly journals Ocean Acidification: Calcifying Marine Organisms

EDIS ◽  
2020 ◽  
Vol 2020 (2) ◽  
pp. 4
Author(s):  
Joseph Henry ◽  
Joshua Patterson ◽  
Lisa Krimsky
Keyword(s):  
Ocean Acidification ◽  
Atmospheric Carbon Dioxide ◽  
Carbonic Acid ◽  
Essential Element ◽  
Co2 Concentration ◽  
Marine Organisms ◽  
Atmospheric Co2 ◽  
Hydrogen Ions ◽  
Excess Hydrogen ◽  
Carbonate Ions

Rising atmospheric carbon dioxide (CO2) concentration leading to ocean acidification is a threat to marine ecosystems and organisms. As atmospheric CO2 rises, CO2 is driven into the ocean. When CO2 combines with seawater it makes carbonic acid. Carbonic acid then breaks down to form a hydrogen ion and a bicarbonate ion. Excess hydrogen ions building up over time result in decreased seawater pH. Furthermore, the excess hydrogen ions combine with carbonate ions in the water, resulting in fewer available carbonate ions for marine calcifiers. These carbonate ions are an essential element for marine calcifiers and their decreased availability is of increasing concern. The overall change in pH and available carbonate ions has been shown to have direct impacts on physiology, behavior, and calcification rates of marine organisms. Coastal Florida boasts an abundance and diversity of calcifying organisms that stand to be impacted by the altered carbonate chemistry resulting from increased atmospheric CO2 levels. This publication will focus on the impacts of ocean acidification on Calcification. Specifically focusing on how calcification in corals, bivalves, echinoderms and planktonic organisms are being impacte.

Effects of Elevated Carbon Dioxide Levels and Temperature on the Life History of the Madeira Mealybug (Hemiptera: Pseudococcidae)

2004 ◽  
Vol 39 (3) ◽  
pp. 387-397 ◽  
Author(s):  
Juang-Horng Chong ◽  
Marc W. van lersel ◽  
Ronald D. Oetting
Keyword(s):  
Carbon Dioxide ◽  
Chemical Composition ◽  
Elevated Co2 ◽  
Atmospheric Carbon Dioxide ◽  
Host Plants ◽  
Co2 Concentration ◽  
Reproductive Period ◽  
Elevated Co2 Concentration ◽  
Elevated Atmospheric Co2 ◽  
Co2 Level

Atmospheric carbon dioxide concentrations and temperatures are increasing and, thus, the interactions between insect herbivores and their host plants in environments of elevated CO2 concentration and temperature must be examined. We investigated the combined effects of elevated atmospheric CO2 concentration (400 and 700 μmol mol−1) and temperature (20, 25 and 30°C) on the development, survival and reproduction of two generations of the Madeira mealybug, Phenacoccus madeirensis Green, and the chemical composition of chrysanthemum, Dendranthema × grandiflora Kitam., leaves. The development of the mealybugs was temperature-driven and was not influenced by the CO2 level or the number of generations. At higher temperatures, the duration to egg eclosion and the developmental time of adult females and males were significantly shortened. More eggs survived to adulthood at higher temperatures. Temperature had no influence on the egg eclosion percentage. The reproductive period of females was shortest at 30°C, while fecundity was highest at 20°C. There was a significantly higher proportion of females at the end of the experiment at lower than at higher temperatures. Elevated CO2 level and temperature did not change the chemical composition (nitrogen and carbon concentrations, and carbon-nitrogen ratio) of the host plants. Relative water content of the leaf tissues was higher at 30°C than other temperature treatments. Our results show that the effects of temperature on the biology of the Madeira mealybug were stronger than that of the elevated CO2 concentration.

scholarly journals Effects of CO<sup>2</sup>, continental distribution, topography and vegetation changes on the climate at the Middle Miocene: a model study

2010 ◽  
Vol 6 (5) ◽  
pp. 675-694 ◽  
Author(s):  
A.-J. Henrot ◽  
L. François ◽  
E. Favre ◽  
M. Butzin ◽  
M. Ouberdous ◽  
...  
Keyword(s):  
Atmospheric Carbon Dioxide ◽  
Middle Miocene ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
The Tibetan Plateau ◽  
Humid Climate ◽  
Vegetation Feedback ◽  
Co2 Concentrations ◽  
Reduced Height ◽  
Atmospheric Co2 Concentrations

Abstract. The Middle Miocene was one of the last warm periods of the Neogene, culminating with the Middle Miocene Climatic Optimum (MMCO, approximatively 17–15 Ma). Several proxy-based reconstructions support warmer and more humid climate during the MMCO. The mechanisms responsible for the warmer climate at the MMCO and particularly the role of the atmospheric carbon dioxide are still highly debated. Here we carried out a series of sensitivity experiments with the model of intermediate complexity Planet Simulator, investigating the contributions of the absence of ice on the continents, the opening of the Central American and Eastern Tethys Seaways, the lowering of the topography on land, the effect of various atmospheric CO2 concentrations and the vegetation feedback. Our results show that a higher than present-day CO2 concentration is necessary to generate a warmer climate at all latitudes at the Middle Miocene, in agreement with the terrestrial proxy reconstructions which suggest high atmospheric CO2 concentrations at the MMCO. Nevertheless, the changes in sea-surface conditions, the lowering of the topography on land and the vegetation feedback also produce significant local warming that may, locally, even be stronger than the CO2 induced temperature increases. The lowering of the topography leads to a more zonal atmospheric circulation and allows the westerly flow to continue over the lowered Plateaus at mid-latitudes. The reduced height of the Tibetan Plateau notably prevents the development of a monsoon-like circulation, whereas the reduction of elevations of the North American and European reliefs strongly increases precipitation from northwestern to eastern Europe. The changes in vegetation cover contribute to maintain and even to intensify the warm and humid conditions produced by the other factors, suggesting that the vegetation-climate interactions could help to improve the model-data comparison.

scholarly journals Effects of CO<sub>2</sub>, continental distribution, topography and vegetation changes on the climate at the Middle Miocene: a model study

2010 ◽  
Vol 6 (2) ◽  
pp. 489-535 ◽  
Author(s):  
A.-J. Henrot ◽  
L. François ◽  
E. Favre ◽  
M. Butzin ◽  
M. Ouberdous ◽  
...  
Keyword(s):  
Atmospheric Carbon Dioxide ◽  
Middle Miocene ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
The Tibetan Plateau ◽  
Humid Climate ◽  
The North ◽  
Co2 Concentrations ◽  
Reduced Height ◽  
Atmospheric Co2 Concentrations

Abstract. The Middle Miocene was one of the last warm periods of the Neogene, culminating with the Middle Miocene Climatic Optimum (MMCO, approximatively 17–15 Ma). Several proxy-based reconstructions support warmer and more humid climate during the MMCO. The mechanisms responsible for the warming at MMCO and particulary the role of the atmospheric carbon dioxide CO2 are still highly debated. Here we carried out a series of sensitivity experiments with the model of intermediate complexity Planet Simulator, investigating the contributions of the absence of ice on the continents, the opening of the Central American and Eastern Tethys Seaways, the lowering of the topography on land, the effect of various atmospheric CO2 concentrations and the vegetation retroaction. Our results show that a higher than present-day CO2 concentration is necessary to generate a warmer climate at all latitudes at the Middle Miocene, in agreement with the terrestrial proxy reconstructions which suggest high atmospheric CO2 concentrations at MMCO. Nevertheless, the changes in sea-surface conditions and the lowering of the topography on land also produce significant local warming that may, locally, even be stronger than the CO2 induced temperature increases. The lowering of the topography leads to a more zonal atmospheric circulation and allows the westerly flow to continue over the lowered Plateaus at mid-latitudes. The reduced height of the Tibetan Plateau notably prevents the development of a monsoon-like circulation, whereas the reduction of elevations of the North American and European reliefs strongly increases precipitation from northwestern to eastern Europe. The changes in vegetation cover contributes to maintain and even to intensify the the warm and humid conditions produced by the other factors, suggesting that the vegetation-climate interactions could help to improve the model-data comparison.

scholarly journals Calibration and Improved Speckle Statistics of IM-CW Lidar for Atmospheric CO2 Measurements

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 737
Author(s):  
Xindong Liang ◽  
Hao Liu ◽  
Tao Chen ◽  
Wei Kong ◽  
Guanglie Hong
Keyword(s):  
Atmospheric Carbon Dioxide ◽  
Continuous Wave ◽  
Co2 Concentration ◽  
Speckle Noise ◽  
Laser Speckle ◽  
Atmospheric Co2 ◽  
Time Averaging ◽  
Optical Antenna ◽  
In Situ Sensor

An intensity modulated, continuous-wave (IM-CW) integrated path differential absorption (IPDA) fiber-based lidar is developed herein for measuring atmospheric carbon dioxide (CO2). There are two main challenges in improving measurement accuracy, which have not been given enough attention in the previous research: one is that temperature sensitivity in optical components causes biases, due to the drift of component characteristic, and the other is that speckle noise deteriorates the signal-to-noise ratio. With the components thermally controlled, a target calibration accuracy of 0.003 dB is realized, corresponding to a CO2 concentration precision of better than 1 ppm for a 1 km path. A moving diffuser can reduce speckle noise by time averaging. In this paper, movement of the diffuser is substituted by the perturbation of the emitted laser beam by using a vibrating motor mounted on the optical antenna. Selecting on and off wavelengths with a small wavelength separation can improve the correlation between two laser speckle fields. These improvements result in the improved accuracy of the IPDA lidar system. Finally, the lidar performance was analyzed after the improvements described above were implemented. The diurnal variations of the atmospheric CO2 concentration using a topographic target were performed, and the results showed good agreement with the data measured by an in situ sensor. The root mean square (rms) of the deviation between the IPDA lidar and the in situ sensor was less than 1.4%.

scholarly journals Atmospheric Carbon Dioxide and Electricity Production Due to Lockdown

2020 ◽  
Vol 12 (22) ◽  
pp. 9397
Author(s):  
Yusri Yusup ◽  
Nur Kamila Ramli ◽  
John Stephen Kayode ◽  
Chee Su Yin ◽  
Sabiq Hisham ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Energy Demand ◽  
Atmospheric Carbon Dioxide ◽  
Phase 1 ◽  
Co2 Concentration ◽  
The United States ◽  
Atmospheric Co2 ◽  
Electricity Production ◽  
Atmospheric Carbon ◽  
The Impact

We analyzed real-time measurements of atmospheric carbon dioxide (CO2), with total electricity production and nationwide restrictions phases in China, the United States of America, Europe, and India due to the novel coronavirus COVID-19 pandemic and its effects on atmospheric CO2. A decline of 3.7% in the global energy demand at about 150 million tonnes of oil equivalent (Mtoe) in the first quarter (Q1) of 2020 was recorded compared to Q1 2019 due to the cutback on international economic activities. Our results showed that: (1) electricity production for the same period in 2018, 2019, and 2020 shrunk at an offset of 9.20%, which resulted in a modest reduction (−1.79%) of atmospheric CO2 to the 2017–2018 CO2 level; (2) a non-seasonal, abrupt, and brief atmospheric CO2 decrease by 0.85% in mid-February 2020 could be due to Phase 1 restrictions in China. The results indicate that electricity production reduction is significant to the short-term variability of atmospheric CO2. It also highlights China’s significant contribution to atmospheric CO2, which suggests that, without the national restriction of activities, CO2 concentration is set to exceed 2019 by 1.79%. Due to the lockdown, it quickly decreased and sustained for two months. The results underscore atmospheric CO2 reductions on the monthly time scale that can be achieved if electricity production from combustible sources was slashed. The result could be useful for cost-benefit analyses on the decrease in electricity production of combustible sources and the impact of this reduction on atmospheric CO2.

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