Archives de catégorie : climate and geology

China and Pakistan Join Forces For World’s Biggest Brown Coal Programme

by Dr. Benny Peiser, April 3, 2017

Chinese engineer and inventor Feng Weizhong has an easy ­answer to how China plans to keep slashing coal use and power-­station emissions while relying on coal to provide at least 55 per cent of its massive energy demand for decades to come. The effervescent Professor Feng, who is also general manager of a large Shanghai power plant, explained to The Australian how the country can contrive to do both at the same time. “Simple! It’s clean coal!”

Greenland was nearly ice-free for extended periods during the Pleistocene

by JM Schaefer et al., Nature, December8, 2016

Here we show that Greenland was deglaciated for extended periods during the Pleistocene epoch (from 2.6 million years ago to 11,700 years ago), based on new measurements of cosmic-ray-produced beryllium and aluminium isotopes (10Be and 26Al) in a bedrock core from beneath an ice core near the GIS summit.

Recent Sea-Level Change at Major Cities

by Rich Taylor, March 29, 2017

Where the ground is stable, typical change appears to be a rise of 1- to 2-mm/y. Rates above 3 mm/y seem to have a substantial component of natural and/or anthropogenic subsidence. Rates above 10 mm/y appear to be a primarily a consequence of human activity, which implies they should be manageable to some degree.

All records in this review are from the website of the Permanent Service for Mean Sea Level.

The Anthropocene: Scientists respond to criticisms of a new geological epoch

by Anthony Watts, March 24, 2017

A team of academics led by the University of Leicester has responded to criticisms of the proposal to formalise a new geological epoch – the Anthropocene.

Geological critics of a formalised Anthropocene have alleged that the idea did not arise from geology; that there is simply not enough physical evidence for it as strata; that it is based more on the future than on the past; that it is more a part of human history than the immensely long history of the Earth; and that it is a political statement, rather than a scientific one.

Dead zones may threaten coral reefs worldwide

by Smithsonian Tropical Research Institute, March 21, 2017

Dead zones affect dozens of coral reefs around the world and threaten hundreds more according to a new study. Watching a massive coral reef die-off on the Caribbean coast of Panama, they suspected it was caused by a dead zone — a low-oxygen area that snuffs out marine life — rather than by ocean warming or acidification.

Journal Reference: Andrew H. Altieri, Seamus B. Harrison, Janina Seemann, Rachel Collin, Robert J. Diaz, Nancy Knowlton. Tropical dead zones and mass mortalities on coral reefs. Proceedings of the National Academy of Sciences, 2017; 201621517 DOI: 10.1073/pnas.1621517114

“No country would find 173 billion barrels of oil in the ground and just leave them there.”

by David Middleton, March 20, 2017

Firstly, the prime minister is exactly correct: “No country would find 173 billion barrels of oil in the ground and just leave them there.” Particularly if those 173 billion barrels were proved reserves.  At $50/bbl, 173 billion barrels is worth a lot of dollars… both US and Canadian.

Secondly, the prime minister is exactly correct here too: “The prime minister has long maintained that developing fossil-fuel resources can go ‘hand in hand’ with fighting climate change.”  Since fighting climate change is about as possible as fighting plate tectonics or entropy, it absolutely “can go ‘hand in hand’ with” developing fossil fuel resources.

IEA finds CO2 emissions flat for third straight year even as global economy grew in 2016

International Energy Agency, March 17, 2017

The biggest drop came from the United States, where carbon dioxide emissions fell 3%, or 160 million tonnes, while the economy grew by 1.6%. The decline was driven by a surge in shale gas supplies and more attractive renewable power that displaced coal. Emissions in the United States last year were at their lowest level since 1992, a period during which the economy grew by 80%.

Ice age thermostat prevented extreme climate cooling

Universitat Autònoma de Barcelona, March 14, 2017
from E. D. Galbraith, S. EgglestonA lower limit to atmospheric CO2 concentrations over the past 800,000 yearsNature Geoscience, 2017

During the ice ages, an unidentified regulatory mechanism prevented atmospheric carbon dioxide concentrations from falling below a level that could have led to runaway cooling, reports a team of researchers. The study suggests the mechanism may have involved the biosphere, as plants and plankton struggled to grow under very low carbon dioxide levels.

California Megaflood: Lessons from a Forgotten Catastrophe

by B. Lynn Ingram, January 1, 2013

 43-day storm that began in December 1861 put central and southern California underwater for up to six months, and it could happen again

Geologic evidence shows that truly massive floods, caused by rainfall alone, have occurred in California every 100 to 200 years. Such floods are likely caused by atmospheric rivers: narrow bands of water vapor about a mile above the ocean that extend for thousands of kilometers.

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

Scientists uncover huge reservoir of melting carbon under Western United States

by Saswata Hier-Majumder et al., February 2017

Pervasive upper mantle melting beneath the western US, Earth and Planetary Science Letters (2017). DOI: 10.1016/j.epsl.2016.12.041

New research published in Earth and Planetary Science Letters describes how scientists have used the world’s largest array of seismic sensors to map a deep-Earth area of melting carbon covering 1.8 million square kilometres. Situated under the Western US, 350km beneath the Earth’s surface, the discovered melting region challenges accepted understanding of how much carbon the Earth contains – much more than previously understood …
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Eocene global warming events driven by ventilation of oceanic dissolved organic carbon

by Ph.F. Sexton et al., Nature, 2011

‘Hyperthermals’ are intervals of rapid, pronounced global warming known from six episodes within the Palaeocene and Eocene epochs (~65–34million years (Myr) ago)12345678910111213. The most extreme hyperthermal was the ~170 thousand year (kyr) interval2 of 5–7°C global warming3 during the Palaeocene–Eocene Thermal Maximum (PETM, 56Myr ago). The PETM is widely attributed to massive release of greenhouse gases from buried sedimentary carbon reservoirs1361114151617, and other, comparatively modest, hyperthermals have also been linked to the release of sedimentary carbon36111617

Egalement, une synthèse en français