Related papers: Glaciological window into the pace of the organic …
Earth's modern atmosphere is highly oxygenated and is a remotely detectable signal of its surface biosphere. However, the lifespan of oxygen-based biosignatures in Earth's atmosphere remains uncertain, particularly for the distant future.…
The possibility of low but nontrivial atmospheric oxygen (O2) levels during the mid-Proterozoic (between 1.8 and 0.8 billion years ago, Ga) has important ramifications for understanding Earth's O2 cycle, the evolution of complex life and…
Molecular oxygen in our atmosphere has increased from less than a part per million in the Archean Eon, to a fraction of a percent in the Proterozoic, and finally to modern levels during the Phanerozoic. The ozone layer formed with the early…
Competing geophysical/geochemical hypotheses for how Earth's surface became oxygenated - organic carbon burial, hydrogen escape to space, and changes in the redox state of volcanic gases - are examined and a more biologically-based…
Ocean planets are volatile rich planets, not present in our Solar System, which are thought to be dominated by deep, global oceans. This results in the formation of high-pressure water ice, separating the planetary crust from the liquid…
Understanding the lifetime of CO2 in the atmosphere is critical for predictions regarding future climate changes. A simple mass conservation analysis presented here generates tight estimations for the atmosphere's retention time constant.…
The history of molecular oxygen (O$_2$) in Earth's atmosphere is still debated; however, geological evidence supports at least two major episodes where O$_2$ increased by an order of magnitude or more: the Great Oxidation Event (GOE) and…
Observations and quantitative understanding of spatio-temporary variations in lower-stratospheric ozone and temperature can provide fingerprints for the mechanisms of ozone depletion and play an important role in testing the impact of…
Changes that occur on our planet can be tracked back to one of two energy sources: the sun and the Earth's internal energy. The motion of tectonic plates, volcanism, mountain building and the reshaping of our planet's surface over geologic…
Aims: The long-term carbon cycle for planets with a surface entirely covered by oceans works differently from that of the present-day Earth because inefficient erosion leads to a strong dependence of the weathering rate on the rate of…
The potential habitability of an exoplanet is traditionally assessed by determining if its orbit falls within the circumstellar `habitable zone' of its star, defined as the distance at which water could be liquid on the surface of a planet…
Essential insights on the characterization and quality of a detectable biosphere are gained by analyzing the effects of its environmental parameters. We compiled environmental and biological properties of the Phanerozoic Eon from various…
The early Earth's environment is controversial. Climatic estimates range from hot to glacial, and inferred marine pH spans strongly alkaline to acidic. Better understanding of early climate and ocean chemistry would improve our knowledge of…
The carbon-silicate cycle regulates the atmospheric $CO_2$ content of terrestrial planets on geological timescales through a balance between the rates of $CO_2$ volcanic outgassing and planetary intake from rock weathering. It is thought to…
Magmatism and volcanism transfer carbon from the solid Earth into the climate system. This transfer may be modulated by the glacial/interglacial cycling of water between oceans and continental ice sheets, which alters the surface loading of…
Increases in atmospheric CO2 and CH4 result from a combination of forcing from anthropogenic emissions and Earth System feedbacks that reduce or amplify the effects of those emissions on atmospheric concentrations. Despite decades of…
Over the past decades, temperature and density of the upper atmosphere show negative trends and decrease of the upper atmospheric temperature is attributed to the declining neutral density. Specifically, nitric oxide (NO) and carbon dioxide…
A model is proposed to explain the observed correlation between monthly fluctuations in atmospheric CO2 concentrations and temperatures. The model relies on the oceans being in a temperature-dependent equilibrium with the atmosphere. When…
1) The annual cycle of atmospheric methane in southern high latitudes is extremely highly correlated with Antarctic sea ice extent. 2) The annual cycle of atmospheric methane in the Arctic is highly correlated with Antarctic or Arctic plus…
The history of the Earth has been marked by major ecological transitions, driven by metabolic innovation, that radically reshaped the composition of the oceans and atmosphere. The nature and magnitude of the earliest transitions, hundreds…