نتایج جستجو برای: atmospheric co2

تعداد نتایج: 142185  

2014
Tianxing Wang Jiancheng Shi Yingying Jing Tianjie Zhao Dabin Ji Chuan Xiong

Global warming induced by atmospheric CO2 has attracted increasing attention of researchers all over the world. Although space-based technology provides the ability to map atmospheric CO2 globally, the number of valid CO2 measurements is generally limited for certain instruments owing to the presence of clouds, which in turn constrain the studies of global CO2 sources and sinks. Thus, it is a p...

2012
Haegeun Chung Peter B. Reich H. Chung

To determine how plant species richness impacts microbial assimilation of new photosynthate, and how this may be modified by atmospheric N deposition, we analyzed the microbial assimilation of recent photosynthate in a 6-year-long field experiment in which plant species richness, atmospheric N deposition, and atmospheric CO2 concentration were manipulated in concert. The depleted dC of fumigati...

2003
DAVID W. LEA

The key scientific uncertainty in the global warming debate is the equilibrium climate sensitivity. Coupled atmosphere–ocean general circulation models predict a wide range of equilibrium climate sensitivities, with a consequently large spread of societal implications. Comparison of models with instrumental data has not been able to reduce the uncertainty in climate sensitivity. An alternative ...

2005
A. Jahn M. Claussen

The importance of the biogeophysical atmosphere-vegetation feedback in comparison with the radiative effect of lower atmospheric CO2 concentrations and the presence of ice sheets at the last glacial maximum (LGM) is investigated with the climate system model CLIMBER-2. Equilibrium experiments reveal that most of the global cooling at the LGM (−5.1C) relative to (natural) present-day conditions ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2016
Richard Levy David Harwood Fabio Florindo Francesca Sangiorgi Robert Tripati Hilmar von Eynatten Edward Gasson Gerhard Kuhn Aradhna Tripati Robert DeConto Christopher Fielding Brad Field Nicholas Golledge Robert McKay Timothy Naish Matthew Olney David Pollard Stefan Schouten Franco Talarico Sophie Warny Veronica Willmott Gary Acton Kurt Panter Timothy Paulsen Marco Taviani

Geological records from the Antarctic margin offer direct evidence of environmental variability at high southern latitudes and provide insight regarding ice sheet sensitivity to past climate change. The early to mid-Miocene (23-14 Mya) is a compelling interval to study as global temperatures and atmospheric CO2 concentrations were similar to those projected for coming centuries. Importantly, th...

Journal: :محیط شناسی 0
شیوا یوسفی دانشجو/دانشگاه شیراز سید فخرالدین افضلی استادیار/دانشگاه شیراز مسعود مسعودی دانشیار/دانشگاه شیراز

growing process of industrialization in different societies, excessive expansion of industries and factories and increase transport industries, push human toward unstable development. among these problem, massive volume of pollutions is also added to the atmosphere. air pollution in industrial societies and cities is more intensive. global warming is one of the major problems of 21 century. co2...

2009
A. Oschlies

The sensitivity of oceanic CO2 uptake to alterations in the marine biological carbon pump, such as brought about by natural or purposeful ocean fertilization, has repeatedly been investigated by studies employing numerical biogeochemical ocean models. It is shown here that the results of such ocean-centered studies are very sensitive to the assumption made about the response of the carbon reser...

2009
Mark Pagani Zhonghui Liu Jonathan LaRiviere Ana Christina Ravelo

Climate sensitivity—the mean global temperature response to a doubling of atmospheric CO2 concentrations through radiative forcing and associated feedbacks—is estimated at 1.5–4.5 ◦C (ref. 1). However, this value incorporates only relatively rapid feedbacks such as changes in atmospheric water vapour concentrations, and the distributions of sea ice, clouds and aerosols2. Earth-system climate se...

2008
X. Jin N. Gruber H. Frenzel S. C. Doney J. C. McWilliams

Using numerical simulations, we quantify the impact of changes in the ocean’s biological pump on the air-sea balance of CO2 by fertilizing a small surface patch in the high-nutrient, low-chlorophyll region of the eastern tropical Pacific with iron. Decade-long fertilization experiments are conducted in a basin-scale, eddy-permitting coupled physical/biogeochemical/ecological model. In contrast ...

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