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The projected timing of abrupt ecological disruption from climate change 期刊论文
NATURE, 2020, 580 (7804) : 496-+
作者:  Gorgulla, Christoph;  Boeszoermenyi, Andras;  Wang, Zi-Fu;  Fischer, Patrick D.;  Coote, Paul W.;  Padmanabha Das, Krishna M.;  Malets, Yehor S.;  Radchenko, Dmytro S.;  Moroz, Yurii S.;  Scott, David A.;  Fackeldey, Konstantin;  Hoffmann, Moritz;  Iavniuk, Iryna;  Wagner, Gerhard;  Arthanari, Haribabu
收藏  |  浏览/下载：80/0  |  提交时间：2020/05/13

As anthropogenic climate change continues the risks to biodiversity will increase over time, with future projections indicating that a potentially catastrophic loss of global biodiversity is on the horizon(1-3). However, our understanding of when and how abruptly this climate-driven disruption of biodiversity will occur is limited because biodiversity forecasts typically focus on individual snapshots of the future. Here we use annual projections (from 1850 to 2100) of temperature and precipitation across the ranges of more than 30,000 marine and terrestrial species to estimate the timing of their exposure to potentially dangerous climate conditions. We project that future disruption of ecological assemblages as a result of climate change will be abrupt, because within any given ecological assemblage the exposure of most species to climate conditions beyond their realized niche limits occurs almost simultaneously. Under a high-emissions scenario (representative concentration pathway (RCP) 8.5), such abrupt exposure events begin before 2030 in tropical oceans and spread to tropical forests and higher latitudes by 2050. If global warming is kept below 2 degrees C, less than 2% of assemblages globally are projected to undergo abrupt exposure events of more than 20% of their constituent species  however, the risk accelerates with the magnitude of warming, threatening 15% of assemblages at 4 degrees C, with similar levels of risk in protected and unprotected areas. These results highlight the impending risk of sudden and severe biodiversity losses from climate change and provide a framework for predicting both when and where these events may occur.


Using annual projections of temperature and precipitation to estimate when species will be exposed to potentially harmful climate conditions reveals that disruption of ecological assemblages as a result of climate change will be abrupt and could start as early as the current decade.


  
Ruthenium isotope vestige of Earth's pre-late-veneer mantle preserved in Archaean rocks 期刊论文
NATURE, 2020, 579 (7798) : 240-+
作者:  Abadie, Valerie;  Kim, Sangman M.;  Lejeune, Thomas;  Palanski, Brad A.;  Ernest, Jordan D.;  Tastet, Olivier;  Voisine, Jordan;  Discepolo, Valentina;  Marietta, Eric, V;  Hawash, Mohamed B. F.;  Ciszewski, Cezary;  Bouziat, Romain;  Panigrahi, Kaushik;  Horwath, Irina;  Zurenski, Matthew A.;  Lawrence, Ian;  Dumaine, Anne;  Yotova, Vania;  Grenier, Jean-Christophe;  Murray, Joseph A.;  Khosla, Chaitan;  Barreiro, Luis B.;  Jabri, Bana
收藏  |  浏览/下载：41/0  |  提交时间：2020/05/13

The accretion of volatile-rich material from the outer Solar System represents a crucial prerequisite for Earth to develop oceans and become a habitable planet(1-4). However, the timing of this accretion remains controversial(5-8). It has been proposed that volatile elements were added to Earth by the late accretion of a late veneer consisting of carbonaceous-chondrite-like material after core formation had ceased(6,9,10). This view could not be reconciled with the ruthenium (Ru) isotope composition of carbonaceous chondrites(5,11), which is distinct from that of the modern mantle(12), or of any known meteorite group(5). As a possible solution, Earth'  s pre-late-veneer mantle could already have contained a fraction of Ru that was not fully extracted by core formation(13). The presence of such pre-late-veneer Ru can only be established if its isotope composition is distinct from that of the modern mantle. Here we report the first high-precision, mass-independent Ru isotope compositions for Eoarchaean ultramafic rocks from southwest Greenland, which display a relative Ru-100 excess of 22 parts per million compared with the modern mantle value. This Ru-100 excess indicates that the source of the Eoarchaean rocks already contained a substantial fraction of Ru before the accretion of the late veneer. By 3.7 billion years ago, the mantle beneath southwest Greenland had not yet fully equilibrated with late accreted material. Otherwise, no Ru isotopic difference relative to the modern mantle would be observed. If constraints from other highly siderophile elements besides Ru are also considered(14), the composition of the modern mantle can only be reconciled if the late veneer contained substantial amounts of carbonaceous-chondrite-like materials with their characteristic Ru-100 deficits. These data therefore relax previous constraints on the late veneer and are consistent with volatile-rich material from the outer Solar System being delivered to Earth during late accretion.


  
Project 57 Air Monitoring Annual Report - Fiscal Year 2013 (October 1, 2012 to September 30, 2013) 科技报告
来源：US Department of Energy (DOE). 出版年： 2014
作者:  Miller, Julianne J.;  McCurdy, Greg;  Mizell, Steve A
收藏  |  浏览/下载：13/0  |  提交时间：2019/04/05
The U.S. Department of Energy (DOE)  National Nuclear Security Administration  Nevada Field Office (NNSA/NFO) is currently working to achieve regulatory closure of radionuclide-contaminated Soils sites under its auspices. Corrective Action Unit (CAU) 415  Project 57 No. 1 Plutonium Dispersion Site is located in Emigrant Valley  Nevada  on Range 4808A of the Nevada Test and Training Range (NTTR)  and consists of one Corrective Action Site (CAS): NAFR-23-02  Pu Contaminated Soil. Closure plans being developed for the CAUs both on and off of the Nevada National Security Site (NNSS) may include postclosure monitoring for the possible release of radioactive contaminants. Determining the potential for transport of radionuclide-contaminated soils under ambient climatic conditions will facilitate an appropriate closure design and postclosure monitoring program. The DOE has authorized the Desert Research Institute (DRI) to conduct field assessments of potential transport of radionuclide-contaminated soil from the Project 57 site during ambient wind events. The assessment is intended to provide site-specific information on meteorological conditions that result in airborne soil particle redistribution  as well as determine which  if any  radiological contaminants may be entrained with the soil particles and estimate their concentrations.