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climate and geology

Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms

by Björn Baresel et al., March 6, 2017, Nature

Since the early days of stratigraphy, mass extinctions were noticed to coincide with major and global sea-level changes1,2 that significantly alter extinction patterns and time-series of geochemical proxies. In the case of the Permian-Triassic boundary mass extinction (PTBME), the system boundary itself has been initially placed during a global eustatic regression3, but was subsequently placed during a global transgression4 …

Shock finding : P-T mass extinction was due to an ice age, and not to warming
climate-debate

Geologic Evidence of Recurring Climate Cycles and Their Implications for the Cause of Global Climate Changes. The Past is the Key to the Future

Don J. Easterbrook, 2011

Department of Geology, Western Washington University, Bellingham, WA 98225, USA

Temperatures have risen approximately a degree or so per century since the coldest part of the Little Ice Age ~500 years ago, but the rise has not been linear. Global temperatures have warmed and cooled many times in 25-35-year cycles, well before the atmospheric CO2 began to rise significantly.

Two episodes of global warming and two episodes of global cooling occurred during the 20th century (Fig. 1). Overall, temperatures during the century rose about the same as the rate of warming per century since the Little Ice Age 500 years ago.