Role of volcanism and impact heating in mass extinction climate shifts.

This study investigates the mechanisms underlying the varied climate changes witnessed during mass extinctions in the Phanerozoic Eon. Climate shifts during mass extinctions have manifested as either predominant global cooling or predominant warming, yet the causes behind these occurrences remain unclear. We emphasize the significance of sedimentary rock temperature in comprehending these climate shifts.

An animal crisis caused by pollution, deforestation, and warming in the late 21st century and exacerbation by nuclear war.

An environmental-animal crisis is currently ongoing and is becoming increasingly severe due to human activity. However, the magnitude, timing, and processes related to this crisis are unclear. This paper clarifies the likely magnitude and timing of animal extinctions and changes in the contribution rates of select causes (global warming, pollution, deforestation, and two hypothetical nuclear conflicts) of animal extinctions during 2000-2300 CE.

Centennial scale sequences of environmental deterioration preceded the end-Permian mass extinction.

The exact drivers for the end-Permian mass extinction (EPME) remain controversial. Here we focus on a ~10,000 yr record from the marine type section at Meishan, China, preceding and covering the onset of the EPME. Analyses of polyaromatic hydrocarbons at sampling intervals representing 1.

Extinction magnitude of animals in the near future.

There have been five major mass extinctions and some minor mass extinctions of animals since early animal diversification 540-520 Myr ago. It is said that a sixth mass extinction is already underway. However, the future extinction magnitude has not been quantitatively estimated.

Maleimide index: a paleo-redox index based on fragmented fossil-chlorophylls obtained by chromic acid oxidation.

The composition of past photosynthetic organisms provides information about the paleo-environment based on the habitat characteristics of photosynthetic organisms. Therefore, analysis of chlorophyll-derived materials from photosynthetic organisms in sedimentary rocks is important for understanding paleo-environmental changes. Fossilized chlorophylls present in sedimentary rocks can be detected by their conversion into maleimides and phthalimides.

Site of asteroid impact changed the history of life on Earth: the low probability of mass extinction.

Sixty-six million years ago, an asteroid approximately 9 km in diameter hit the hydrocarbon- and sulfur-rich sedimentary rocks in what is now Mexico. Recent studies have shown that this impact at the Yucatan Peninsula heated the hydrocarbon and sulfur in these rocks, forming stratospheric soot and sulfate aerosols and causing extreme global cooling and drought. These events triggered a mass extinction, including dinosaurs, and led to the subsequent macroevolution of mammals.

Effects of soil erosion and anoxic-euxinic ocean in the Permian-Triassic marine crisis.

The largest mass extinction of biota in the Earth's history occurred during the Permian-Triassic transition and included two extinctions, one each at the latest Permian (first phase) and earliest Triassic (second phase). High seawater temperature in the surface water accompanied by euxinic deep-intermediate water, intrusion of the euxinic water to the surface water, a decrease in pH, and hypercapnia have been proposed as direct causes of the marine crisis. For the first-phase extinction, we here add a causal mechanism beginning from massive soil and rock erosion and leading to algal blooms, release of toxic components, asphyxiation, and oxygen-depleted nearshore bottom water that created environmental stress for nearshore marine animals.

Global climate change driven by soot at the K-Pg boundary as the cause of the mass extinction.

The mass extinction of life 66 million years ago at the Cretaceous/Paleogene boundary, marked by the extinctions of dinosaurs and shallow marine organisms, is important because it led to the macroevolution of mammals and appearance of humans. The current hypothesis for the extinction is that an asteroid impact in present-day Mexico formed condensed aerosols in the stratosphere, which caused the cessation of photosynthesis and global near-freezing conditions. Here, we show that the stratospheric aerosols did not induce darkness that resulted in milder cooling than previously thought.