scholarly journals Emissions halted of the potent greenhouse gas SF<sub>5</sub>CF<sub>3</sub>

2012 ◽  
Vol 12 (1) ◽  
pp. 869-885 ◽  
Author(s):  
W. T. Sturges ◽  
D. E. Oram ◽  
J. C. Laube ◽  
C. E. Reeves ◽  
M. J. Newland ◽  
...  

Abstract. Long term measurements in background air (Cape Grim, Tasmania) and firn air (NEEM, Greenland) of the "super" greenhouse gas SF5CF3 show that emissions declined after the late 1990s, having grown since the 1950s, and became indistinguishable from zero after 2003. It is concluded that this is due to the cessation of global production of perfluorooctyl sulfonate-based fluorochemicals. An earlier observation of closely correlated atmospheric abundances of SF5CF3 and SF6 are shown here to have likely been purely coincidental, as their respective trends diverged after 2002. Due to its long lifetime (ca. 900 yr), atmospheric concentrations of SF5CF3 have not declined, and it is now well mixed between hemispheres, as is also shown here from interhemispheric aircraft measurements. Total cumulative emissions of SF5CF3 amount to around 5 kT.

2012 ◽  
Vol 12 (8) ◽  
pp. 3653-3658 ◽  
Author(s):  
W. T. Sturges ◽  
D. E. Oram ◽  
J. C. Laube ◽  
C. E. Reeves ◽  
M. J. Newland ◽  
...  

Abstract. Long term measurements in background air (Cape Grim, Tasmania) and firn air (NEEM, Greenland) of the potent long-lived greenhouse gas SF5CF3 show that emissions declined after the late 1990s, having grown since the 1950s, and became indistinguishable from zero after 2003. The timing of this decline suggests that emissions of this gas may have been related to the production of certain fluorochemicals; production of which have been recently phased out. An earlier observation of closely correlated atmospheric abundances of SF5CF3 and SF6 are shown here to have likely been purely coincidental, as their respective trends diverged after 2002. Due to its long lifetime (ca. 900 yr), atmospheric concentrations of SF5CF3 have not declined, and it is now well mixed between hemispheres, as is also shown here from interhemispheric aircraft measurements. Total cumulative emissions of SF5CF3 amount to around 5 kT.


2009 ◽  
pp. 107-120 ◽  
Author(s):  
I. Bashmakov

On the eve of the worldwide negotiations of a new climate agreement in December 2009 in Copenhagen it is important to clearly understand what Russia can do to mitigate energy-related greenhouse gas emissions in the medium (until 2020) and in the long term (until 2050). The paper investigates this issue using modeling tools and scenario approach. It concludes that transition to the "Low-Carbon Russia" scenarios must be accomplished in 2020—2030 or sooner, not only to mitigate emissions, but to block potential energy shortages and its costliness which can hinder economic growth.


1992 ◽  
Vol 46 (1) ◽  
pp. 225-264 ◽  
Author(s):  
Raymond F. Hopkins

The principles and norms adopted by the regime governing food aid in the 1950s have changed substantially during the subsequent three decades. Explaining the changes necessarily includes analyzing the efforts of an international epistemic community consisting of economic development specialists, agricultural economists, and administrators of food aid. According to the initial regime principles, food aid should be provided from donors' own surplus stocks, should supplement the usual commercial food imports in recipient countries, should be given under short-term commitments sensitive to the political and economic goals of donors, and should directly feed hungry people. As a result of following these principles, the epistemic community and other critics argued, food aid often had the adverse effects of reducing local production of food in recipient countries and exacerbating rather than alleviating hunger. The epistemic community (1) developed and proposed ideas for more efficiently supplying food aid and avoiding “disincentive” effects and (2) pushed for reforms to make food aid serve as the basis for the recipients' economic development and to target it at addressing long-term food security problems. The ideas of the international epistemic community have increasingly received support from international organizations and the governments of donor and recipient nations. Most recently, they have led to revisions of the U.S. food aid program passed by Congress in October 1990 and signed into law two months later. As the analysis of food aid reform demonstrates, changes in the international regime have been incremental, rather than radical. Moreover, the locus for the change has shifted from an American-centered one in the 1950s to a more international one in recent decades.


1999 ◽  
Vol 13 (2) ◽  
pp. 503-517 ◽  
Author(s):  
Corinne Galy-Lacaux ◽  
Robert Delmas ◽  
Georges Kouadio ◽  
Sandrine Richard ◽  
Philippe Gosse

Author(s):  
Ingeborg Levin ◽  
Samuel Hammer ◽  
Elke Eichelmann ◽  
Felix R. Vogel

Independent verification of greenhouse gas emissions reporting is a legal requirement of the Kyoto Protocol, which has not yet been fully accomplished. Here, we show that dedicated long-term atmospheric measurements of greenhouse gases, such as carbon dioxide (CO 2 ) and methane (CH 4 ), continuously conducted at polluted sites can provide the necessary tool for this undertaking. From our measurements at the semi-polluted Heidelberg site in the upper Rhine Valley, we find that in the catchment area CH 4 emissions decreased on average by 32±6% from the second half of the 1990s until the first half of the 2000s, but the observed long-term trend of emissions is considerably smaller than that previously reported for southwest Germany. In contrast, regional fossil fuel CO 2 levels, estimated from high-precision 14 CO 2 observations, do not show any significant decreasing trend since 1986, in agreement with the reported emissions for this region. In order to provide accurate verification, these regional measurements would best be accompanied by adequate atmospheric transport modelling as required to precisely determine the relevant catchment area of the measurements. Furthermore, reliable reconciliation of reported emissions will only be possible if these are known at high spatial resolution in the catchment area of the observations. This information should principally be available in all countries that regularly report their greenhouse gas emissions to the United Nations Framework Convention on Climate Change.


2021 ◽  
Author(s):  
Fabien Maussion ◽  
Quentin Lejeune ◽  
Ben Marzeion ◽  
Matthias Mengel ◽  
David Rounce ◽  
...  

&lt;p&gt;Mountain glaciers have a delayed response to climate change and are expected to continue to melt long after greenhouse gas emissions have stopped, with consequences both for sea-level rise and water resources. In this contribution, we use the Open Global Glacier Model (OGGM) to compute global glacier volume and runoff changes until the year 2300 under a suite of stylized greenhouse gas emission characterized by (i) the year at which anthropogenic emissions culminate, (ii) their reduction rates after peak emissions and (iii) whether they lead to a long-term global temperature stabilization or decline. We show that even under scenarios that achieve the Paris Agreement goal of holding global-mean temperature below 2&amp;#8201;&amp;#176;C, glacier contribution to sea-level rise will continue well beyond 2100. Because of this delayed response, the year of peak emissions (i.e. the timing of mitigation action) has a stronger influence on mit-term global glacier change than other emission scenario characteristics, while long-term change is dependent on all factors. We also discuss the impact of early climate mitigation on regional glacier change and the consequences for glacier runoff, both short-term (where some basins are expected to experience an increase of glacier runoff) and long-term (where all regions are expecting a net-zero or even negative glacier contribution to total runoff), underlining the importance of mountain glaciers for regional water availability at all timescales.&lt;/p&gt;


2012 ◽  
Vol 9 (3) ◽  
pp. 3693-3738 ◽  
Author(s):  
M. S. Carter ◽  
K. S. Larsen ◽  
B. Emmett ◽  
M. Estiarte ◽  
C. Field ◽  
...  

Abstract. In this study, we compare annual fluxes of methane (CH4), nitrous oxide (N2O) and soil respiratory carbon dioxide (CO2) measured at nine European peatlands (n = 4) and shrublands (n = 5). The sites range from northern Sweden to Spain, covering a span in mean annual air temperature from 0 to 16 °C, and in annual precipitation from 300 to 1300 mm yr−1. The effects of climate change, including temperature increase and prolonged drought, were tested at five shrubland sites. At one peatland site, the long-term (>30 yr) effect of drainage was assessed, while increased nitrogen deposition was investigated at three peatland sites. The shrublands were generally sinks for atmospheric CH4 whereas the peatlands were CH4 sources, with fluxes ranging from −519 to +6890 mg CH4-C m−2 yr−1 across the studied ecosystems. At the peatland sites, annual CH4 emission increased with mean annual air temperature, while a negative relationship was found between net CH4 uptake and the soil carbon stock at the shrubland sites. Annual N2O fluxes were generally small ranging from –14 to 42 mg N2O-N m−2 yr−1. Highest N2O emission occurred at the sites that had highest concentration of nitrate (NO3−) in soil water. Furthermore, experimentally increased NO3− deposition led to increased N2O efflux, whereas prolonged drought and long-term drainage reduced the N2O efflux. Soil CO2 emissions in control plots ranged from 310 to 732 g CO2-C m−2 yr−1. Drought and long-term drainage generally reduced the soil CO2 efflux, except at a~hydric shrubland where drought tended to increase soil respiration. When comparing the fractional importance of each greenhouse gas to the total numerical global warming response, the change in CO2 efflux dominated the response in all treatments (ranging 71–96%), except for NO3− addition where 89% was due to change in CH4 emissions. Thus, in European peatlands and shrublands the feedback to global warming induced by the investigated anthropogenic disturbances will be dominated by variations in soil CO2 fluxes.


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