Archives par mot-clé : Carbon

Cycle du carbone, l’éclairage de trois nouvelles publications

by Uzbek, 11 septembre 2018 in Climat,Environnemen,Energie

Trois nouvelle études publiées en août 2018 apportent un éclairage nouveau sur le cycle du carbone. La première, publiée dans la revue Nature [1] montre que le taux de croissance du CO2  dans l’atmosphère est très sensible aux changements observés dans le stockage de l’eau terrestre. Les deux autres publiées respectivement dans Nature Geoscience [2] et dans Nature [3] montrent une tendance à l’augmentation du puits de carbone terrestre grâce notamment  aux modifications de l’usage des sols sous l’influence des activités humaines.

End of the Little Ice Age in the Alps forced by industrial black carbon

by Thomas H. Painter et al., September 17, 2018 in PNAS

The end of the Little Ice Age in the European Alps has long been a paradox to glaciology and climatology. Glaciers in the Alps began to retreat abruptly in the mid-19th century, but reconstructions of temperature and precipitation indicate that glaciers should have instead advanced into the 20th century. We observe that industrial black carbon in snow began to increase markedly in the mid-19th century and show with simulations that the associated increases in absorbed sunlight by black carbon in snow and snowmelt were of sufficient magnitude to cause this scale of glacier retreat. This hypothesis offers a physically based explanation for the glacier retreat that maintains consistency with the temperature and precipitation reconstructions.

Evaluating the contribution of black carbon to climate change

by Nagoya University, September 11, 2018 in ScienceDaily

Black carbon refers to tiny carbon particles that form during incomplete combustion of carbon-based fuels. Black carbon particles absorb sunlight, so they are considered to contribute to global warming. However, the contribution of black carbon to the heating of the Earth’s atmosphere is currently uncertain. Models that can accurately assess the warming effect of black carbon on our atmosphere are needed so that we can understand the contribution of these tiny carbon particles to climate change. The mixing state of black carbon particles and their particle size strongly influence their ability to absorb sunlight, but current models have large uncertainties associated with both particle size and mixing state.

Soil carbon debt of 12,000 years of human land use

by J. Sanderman et al., July 2017 in PNAS

Human appropriation of land for agriculture has greatly altered the terrestrial carbon balance, creating a large but uncertain car- bon debt in soils. Estimating the size and spatial distribution of soil organic carbon (SOC) loss due to land use and land cover change has been difficult but is a critical step in understand- ing whether SOC sequestration can be an effective climate mitigation strategy.

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