Feed aggregator

Early Earth: Atmosphere's solar shock

Nature Geoscience Advanced Online - Sun, 05/22/2016 - 23:00

Nature Geoscience. doi:10.1038/ngeo2728

Author: Ramses Ramirez

Frequent storms on the young Sun would have ejected energetic particles and compressed Earth's magnetosphere. Simulations suggest that the particles penetrated the atmosphere and initiated reactions that warmed the planet and fertilized life.

Prebiotic chemistry and atmospheric warming of early Earth by an active young Sun

Nature Geoscience Advanced Online - Sun, 05/22/2016 - 23:00

Nature Geoscience. doi:10.1038/ngeo2719

Authors: V. S. Airapetian, A. Glocer, G. Gronoff, E. Hébrard & W. Danchi

Nitrogen is a critical ingredient of complex biological molecules. Molecular nitrogen, however, which was outgassed into the Earth’s early atmosphere, is relatively chemically inert and nitrogen fixation into more chemically reactive compounds requires high temperatures. Possible mechanisms of nitrogen fixation include lightning, atmospheric shock heating by meteorites, and solar ultraviolet radiation. Here we show that nitrogen fixation in the early terrestrial atmosphere can be explained by frequent and powerful coronal mass ejection events from the young Sun—so-called superflares. Using magnetohydrodynamic simulations constrained by Kepler Space Telescope observations, we find that successive superflare ejections produce shocks that accelerate energetic particles, which would have compressed the early Earth’s magnetosphere. The resulting extended polar cap openings provide pathways for energetic particles to penetrate into the atmosphere and, according to our atmospheric chemistry simulations, initiate reactions converting molecular nitrogen, carbon dioxide and methane to the potent greenhouse gas nitrous oxide as well as hydrogen cyanide, an essential compound for life. Furthermore, the destruction of N2, CO2 and CH4 suggests that these greenhouse gases cannot explain the stability of liquid water on the early Earth. Instead, we propose that the efficient formation of nitrous oxide could explain a warm early Earth.

Organic carbon decomposition rates controlled by water retention time across inland waters

Nature Geoscience Advanced Online - Sun, 05/22/2016 - 23:00

Nature Geoscience. doi:10.1038/ngeo2720

Authors: Núria Catalán, Rafael Marcé, Dolly N. Kothawala & Lars. J. Tranvik

The loss of organic carbon during passage through the continuum of inland waters from soils to the sea is a critical component of the global carbon cycle. Yet, the amount of organic carbon mineralized and released to the atmosphere during its transport remains an open question, hampered by the absence of a common predictor of organic carbon decay rates. Here we analyse a compilation of existing field and laboratory measurements of organic carbon decay rates and water residence times across a wide range of aquatic ecosystems and climates. We find a negative relationship between the rate of organic carbon decay and water retention time across systems, entailing a decrease in organic carbon reactivity along the continuum of inland waters. We find that the half-life of organic carbon is short in inland waters (2.5 ± 4.7 yr) compared to terrestrial soils and marine ecosystems, highlighting that freshwaters are hotspots of organic carbon degradation. Finally, we evaluate the response of organic carbon decay rates to projected changes in runoff. We calculate that regions projected to become drier or wetter as the global climate warms will experience changes in organic carbon decay rates of up to about 10%, which illustrates the influence of hydrological variability on the inland waters carbon cycle.

Recent slowing of Atlantic overturning circulation as a recovery from earlier strengthening

Nature Geoscience Advanced Online - Sun, 05/22/2016 - 23:00

Nature Geoscience. doi:10.1038/ngeo2715

Authors: Laura C. Jackson, K. Andrew Peterson, Chris D. Roberts & Richard A. Wood

The Atlantic meridional overturning circulation (AMOC) has weakened substantially over the past decade. Some weakening may already have occurred over the past century, and global climate models project further weakening in response to anthropogenic climate change. Such a weakening could have significant impacts on the surface climate. However, ocean model simulations based on historical conditions have often found an increase in overturning up to the mid-1990s, followed by a decrease. It is therefore not clear whether the observed weakening over the past decade is part of decadal variability or a persistent weakening. Here we examine a state-of-the-art global-ocean reanalysis product, GloSea5, which covers the years 1989 to 2015 and closely matches observations of the AMOC at 26.5° N, capturing the interannual variability and decadal trend with unprecedented accuracy. The reanalysis data place the ten years of observations—April 2004 to February 2014—into a longer-term context and suggest that the observed decrease in the overturning circulation is consistent with a recovery following a previous increase. We find that density anomalies that propagate southwards from the Labrador Sea are the most likely cause of these variations. We conclude that decadal variability probably played a key role in the decline of the AMOC observed over the past decade.

Analysis: ‘Another Antarctic Sea Level Rise False Alarm’ – Climate fear claims ‘grievously wrong’

Climate Depot - Sun, 05/22/2016 - 19:11
Another Antarctic Sea Level Rise False Alarm http://judithcurry.com/2016/05/22/another-antarctic-sea-level-rise-false-alarm by Rud Istvan Aitken et. al. in Nature newly comports to confirm 2015 fears about instability of the Totten Glacier in Eastern Antarctica. This could ‘suddenly’ raise sea level as much as 4 meters! (Or, based on the abstract, maybe only 0.9 meters in ‘modern scale configuration’, [...]

1959 Paper Shows Most Warming Before 1945 …Arctic Warmed 7.7°C, Sea Level Rose 8 mm/yr

Climate Depot - Sun, 05/22/2016 - 10:08
1959 Paper Shows Most Warming Before 1945 …Arctic Warmed 7.7°C, Sea Level Rose 8 mm/yr http://notrickszone.com/2016/05/22/1959-paper-shows-most-warming-before-1945-arctic-warmed-7-7c-sea-level-rose-8-mmyr/ The following clearly shows a complete lack of correlation between CO2 and temperature. Most of the 20th century warming occurred before 1945, and clearly was linked to natural factors at time the planet was emerging from the Little Ice [...]

Trump to cause seas to rise?! Climate activist warns Florida property owners: If Trump elected ‘sell now while sea levels still leave you something to sell’

Climate Depot - Sat, 05/21/2016 - 10:06
Climate activist Tom Burke, the former head of Friends of the Earth UK, and currently chairman of E3G, a group which works to accelerate the transition to a “low-carbon” economy, has a warning to property owners in Florida if presumptive nominee Donald Trump is elected President. A Trump presidency “sends a clear signal to people who have [...]

Warmist declares: ‘Trump Cannot Derail Paris UN Climate Deal’

Climate Depot - Sat, 05/21/2016 - 09:32
Trump Cannot Derail Paris Climate Deal http://ecowatch.com/2016/05/21/trump-paris-climate-agreement/ “Trump can repudiate the agreement, but it won’t make a scrap of difference to the… — gReader Pro

Hypocrite! Leo DiCaprio takes private jet to collect environmental award

Climate Depot - Fri, 05/20/2016 - 21:13
http://pagesix.com/2016/05/20/hypocrite-leo-takes-private-jet-to-collect-green-award/   Leo DiCaprio picked up an environmental award in NYC this week — but hypocritically expanded his carbon footprint by 8,000 miles when he obtained the honor, by taking a private jet from Cannes, then flying straight back to France on another jet for a model-packed fund-raiser a night later. DiCaprio was at the [...]

Even quantum pigeons may thrive together [Letters (Online Only)]

PNAS Early Edition Articles - Fri, 05/20/2016 - 15:10
In a recent issue of PNAS, Aharonov et al. (1) present interesting results on correlations between three particles (“pigeons”), 1, 2 and 3, each having access to two quantum states (“boxes” and “pigeonholes”) | L > and | R >. For a preselected three-particle state |in > = | +...

Quantum violations of the pigeonhole principle [Letters (Online Only)]

PNAS Early Edition Articles - Fri, 05/20/2016 - 14:26
In our paper in PNAS (1), we describe a quantum violation of the pigeonhole principle. We describe a situation (involving pre- and postselection) in which we put three particles in two boxes and we never find two particles in the same box. We presented both a “strong measurement” analysis and...

Neural control of exploratory behavior [Neuroscience]

PNAS Early Edition Articles - Fri, 05/20/2016 - 13:40
Exploratory drive is one of the most fundamental emotions, of all organisms, that are evoked by novelty stimulation. Exploratory behavior plays a fundamental role in motivation, learning, and well-being of organisms. Diverse exploratory behaviors have been described, although their heterogeneity is not certain because of the lack of solid experimental...

Odor combinations influence mouse behavior [Neuroscience]

PNAS Early Edition Articles - Fri, 05/20/2016 - 13:40
The mechanisms by which odors induce instinctive behaviors are largely unknown. Odor detection in the mouse nose is mediated by >1, 000 different odorant receptors (ORs) and trace amine-associated receptors (TAARs). Odor perceptions are encoded combinatorially by ORs and can be altered by slight changes in the combination of activated...

Role of a brain-gut axis in energy balance [Physiology]

PNAS Early Edition Articles - Fri, 05/20/2016 - 13:40
The starvation-inducible coactivator cAMP response element binding protein (CREB)–cAMP-regulated transcription coactivator (Crtc) has been shown to promote starvation resistance in Drosophila by up-regulating CREB target gene expression in neurons, although the underlying mechanism is unclear. We found that Crtc and its binding partner CREB enhance energy homeostasis by stimulating the...

Analysis: NOAA & NASA altering past temperature data to promote ‘global warming’

Climate Depot - Fri, 05/20/2016 - 13:30
In 1978, NOAA showed 0.6 degrees global cooling since 1975 at the surface and in balloon data. The cooling was present in both hemispheres. 1520-0493(1978)106<0755:GTVSMA>2.0.CO;2 The National Academy of Sciences knew about this cooling in 1975. sn1975_climate_change_chilling_possibilities-1.pdf This cooling was seen in the vast majority of US stations and is still present in the untampered US [...]

‘When 32.6% becomes 97%— the bald-faced (consensus) lie that changed the western world’

Climate Depot - Fri, 05/20/2016 - 13:19
What the president was referring to was a 2013 paper by the University of Queensland’s John Cook. In his research, Cook studied 11,994 papers published between 1991 and 2011 that mentioned the search words “global warming” and “global climate change.” Guess what Cook found? Only 32.6% of the papers endorsed the view of anthropogenic (man-made) [...]

Al Gore’s Film 10 Years Later: Warmists gush: ‘The Slideshow That Saved The World’

Climate Depot - Fri, 05/20/2016 - 12:52
Did any of this actually “save the world?” OK, you got us. Ten years after the movie’s release, climate change is still a growing threat and a polarizing issue, with record-breaking heat unable to stop skeptics from tossing snowballs on the Senate floor. But we’re also seeing corporate, political, and societal mobilization against the crisis [...]
Syndicate content