scholarly journals Growth and rapid succession of methanotrophs effectively limit methane release during lake overturn

2019 ◽  
Author(s):  
Magdalena J. Mayr ◽  
Matthias Zimmermann ◽  
Jason Dey ◽  
Andreas Brand ◽  
Bernhard Wehrli ◽  
...  

AbstractLakes and reservoirs contribute substantially to atmospheric concentrations of the potent greenhouse gas methane. Lacustrine sediments produce large amounts of methane, which accumulate in oxygen-depleted hypolimnia of stratified lakes. Due to climate change and progressing eutrophication, the number of lakes with hypolimnetic methane storage may increase in the future. However, whether stored methane eventually reaches the atmosphere during lake overturn is a matter of controversy and depends critically on the response of the methanotroph assemblage. We show that the methanotroph assemblage in a mixing lake underwent both a substantial bloom and ecological succession. As a result, the methane oxidation capacity of the mixed layer kept pace with the methane supplied from the hypolimnion and most of the stored methane was oxidized. This previously unknown aspect of freshwater methanotroph ecology represents an effective mechanism limiting methane transfer from lakes to the atmosphere.

2021 ◽  
Vol 13 (6) ◽  
pp. 3170
Author(s):  
Avri Eitan

Evidence shows that global climate change is increasing over time, and requires the adoption of a variety of coping methods. As an alternative for conventional electricity systems, renewable energies are considered to be an important policy tool for reducing greenhouse gas emissions, and therefore, they play an important role in climate change mitigation strategies. Renewable energies, however, may also play a crucial role in climate change adaptation strategies because they can reduce the vulnerability of energy systems to extreme events. The paper examines whether policy-makers in Israel tend to focus on mitigation strategies or on adaptation strategies in renewable energy policy discourse. The results indicate that despite Israel’s minor impact on global greenhouse gas emissions, policy-makers focus more on promoting renewable energies as a climate change mitigation strategy rather than an adaptation strategy. These findings shed light on the important role of international influence—which tends to emphasize mitigation over adaptation—in motivating the domestic policy discourse on renewable energy as a coping method with climate change.


2013 ◽  
Vol 20 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Stephen M. Ogle ◽  
Lydia Olander ◽  
Lini Wollenberg ◽  
Todd Rosenstock ◽  
Francesco Tubiello ◽  
...  

Author(s):  
Pietro Croce ◽  
Paolo Formichi ◽  
Filippo Landi

<p>The impact of climate change on climatic actions could significantly affect, in the mid-term future, the design of new structures as well as the reliability of existing ones designed in accordance to the provisions of present and past codes. Indeed, current climatic loads are defined under the assumption of stationary climate conditions but climate is not stationary and the current accelerated rate of changes imposes to consider its effects.</p><p>Increase of greenhouse gas emissions generally induces a global increase of the average temperature, but at local scale, the consequences of this phenomenon could be much more complex and even apparently not coherent with the global trend of main climatic parameters, like for example, temperature, rainfalls, snowfalls and wind velocity.</p><p>In the paper, a general methodology is presented, aiming to evaluate the impact of climate change on structural design, as the result of variations of characteristic values of the most relevant climatic actions over time. The proposed procedure is based on the analysis of an ensemble of climate projections provided according a medium and a high greenhouse gas emission scenario. Factor of change for extreme value distribution’s parameters and return values are thus estimated in subsequent time windows providing guidance for adaptation of the current definition of structural loads.</p><p>The methodology is illustrated together with the outcomes obtained for snow, wind and thermal actions in Italy. Finally, starting from the estimated changes in extreme value parameters, the influence on the long-term structural reliability can be investigated comparing the resulting time dependent reliability with the reference reliability levels adopted in modern Structural codes.</p>


2021 ◽  
Author(s):  
Isabell Böhm

Climate change litigation is becoming increasingly important. This thesis deals with the question whether state liability claims against Germany or the EU can be justified, if commitments to reduce greenhouse gas emissions are not met. For this purpose, the claim under public liability according to § 839 German Civil Code in connection with Art. 34 German Basic Law, the liability of the EU-Member States and the liability of the European Union according to Art. 340 II TFEU are discussed. At the end of the thesis, considerations on the practical perspectives of state liability are made in order to improve their prospects of success.


2005 ◽  
Vol 31 ◽  
pp. 279-309 ◽  
Author(s):  
Axel Gosseries

Evidence provided by the scientific community strongly suggests that limits should be placed on greenhouse gas (GHG) emissions. This means that states, firms, and individuals will have to face potentially serious burdens if they are to implement these limits. Which principles of justice should guide a global regime aimed at reducing greenhouse gas (GHG) emissions originating from human activities, and most notably from CO2 emissions? This is both a crucial and difficult question. Admittedly, perhaps this question is too ambitious, given the uncertainties and complexities characterizing the issue of climate change. Yet, rather than listing them all at this stage, let us address the question in a straightforward manner, introducing some of these complexities as the need arises.


2016 ◽  
Author(s):  
Malte Meinshausen ◽  
Elisabeth Vogel ◽  
Alexander Nauels ◽  
Katja Lorbacher ◽  
Nicolai Meinshausen ◽  
...  

Abstract. Atmospheric greenhouse gas concentrations are at unprecedented, record-high levels compared to pre-industrial reconstructions over the last 800,000 years. Those elevated greenhouse gas concentrations warm the planet and together with net cooling effects by aerosols, they are the reason of observed climate change over the past 150 years. An accurate representation of those concentrations is hence important to understand and model recent and future climate change. So far, community efforts to create composite datasets with seasonal and latitudinal information have focused on marine boundary layer conditions and recent trends since 1980s. Here, we provide consolidated data sets of historical atmospheric (volume) mixing ratios of 43 greenhouse gases specifically for the purpose of climate model runs. The presented datasets are based on AGAGE and NOAA networks and a large set of literature studies. In contrast to previous intercomparisons, the new datasets are latitudinally resolved, and include seasonality over the period between year 0 to 2014. We assimilate data for CO2, methane (CH4) and nitrous oxide (N2O), 5 chlorofluorocarbons (CFCs), 3 hydrochlorofluorocarbons (HCFCs), 16 hydrofluorocarbons (HFCs), 3 halons, methyl bromide (CH3Br), 3 perfluorocarbons (PFCs), sulfur hexafluoride (SF6), nitrogen triflouride (NF3) and sulfuryl fluoride (SO2F2). We estimate 1850 annual and global mean surface mixing ratios of CO2 at 284.3 ppmv, CH4 at 808.2 ppbv and N2O at 273.0 ppbv and quantify the seasonal and hemispheric gradients of surface mixing ratios. Compared to earlier intercomparisons, the stronger implied radiative forcing in the northern hemisphere winter (due to the latitudinal gradient and seasonality) may help to improve the skill of climate models to reproduce past climate and thereby reduce uncertainty in future projections.


Author(s):  
Farshid Zabihian ◽  
Alan S. Fung

Nowadays, the global climate change has been a worldwide concern and the greenhouse gases (GHG) emissions are considered as the primary cause of that. The United Nations Conference on Environment and Development (UNCED) divided countries into two groups: Annex I Parties and Non-Annex I Parties. Since Iran and all other countries in the Middle East are among Non-Annex I Parties, they are not required to submit annual GHG inventory report. However, the global climate change is a worldwide phenomenon so Middle Eastern countries should be involved and it is necessary to prepare such a report at least unofficially. In this paper the terminology and the methods to calculate GHG emissions will first be explained and then GHG emissions estimates for the Iranian power plants will be presented. Finally the results will be compared with GHG emissions from the Canadian electricity generation sector. The results for the Iranian power plants show that in 2005 greenhouse gas intensity for steam power plants, gas turbines and combined cycle power plants were 617, 773, and 462 g CO2eq/kWh, respectively with the overall intensity of 610 g CO2eq/kWh for all thermal power plants. This GHG intensity is directly depend on efficiency of power plants. Whereas, in 2004 GHG intensity for electricity generation sector in Canada for different fuels were as follows: Coal 1010, refined petroleum products 640, and natural gas 523 g CO2eq/kWh, which are comparable with same data for Iran. For average GHG intensity in the whole electricity generation sector the difference is much higher: Canada 222 vs. Iran 610g CO2eq/kWh. The reason is that in Canada a considerable portion of electricity is generated by hydro-electric and nuclear power plants in which they do not emit significant amount of GHG emissions. The average GHG intensity in electricity generation sector in Iran between 1995 and 2005 experienced 13% reduction. While in Canada at the same period of time there was 21% increase. However, the results demonstrate that still there are great potentials for GHG emissions reduction in Iran’s electricity generation sector.


2020 ◽  
Author(s):  
Christian Schott

<p><b>Abstract </b></p> <p>While the pedagogical benefits of fieldtrips have long been recognised our ever increasing understanding of the impacts of flying on climate change is presenting educators with a poignant dilemma; the many benefits long associated with international fieldtrips are at odds with the world community’s needs in limiting/halting climatic change. In response, the paper presents the concept of a VR-based virtual fieldtrip as an innovative and carbon-sensitive type of (educational) travel. The paper not only makes the case for virtual fieldtrips as a meaningful learning tool but also explores both the virtual fieldtrip’s impact on Greenhouse Gas emissions and climate change-related learning. On both accounts the initial findings in this paper are very encouraging. More in-depth research is now required to not only develop a deeper understanding of the full breadth of benefits, but also of the diverse weaknesses presented by virtual fieldtrips and how to negotiate them.</p>


Fluids ◽  
2021 ◽  
Vol 6 (10) ◽  
pp. 360
Author(s):  
Catherine Vreugdenhil ◽  
Bishakhdatta Gayen

Ocean convection is a key mechanism that regulates heat uptake, water-mass transformation, CO2 exchange, and nutrient transport with crucial implications for ocean dynamics and climate change. Both cooling to the atmosphere and salinification, from evaporation or sea-ice formation, cause surface waters to become dense and down-well as turbulent convective plumes. The upper mixed layer in the ocean is significantly deepened and sustained by convection. In the tropics and subtropics, night-time cooling is a main driver of mixed layer convection, while in the mid- and high-latitude regions, winter cooling is key to mixed layer convection. Additionally, at higher latitudes, and particularly in the sub-polar North Atlantic Ocean, the extensive surface heat loss during winter drives open-ocean convection that can reach thousands of meters in depth. On the Antarctic continental shelf, polynya convection regulates the formation of dense bottom slope currents. These strong convection events help to drive the immense water-mass transport of the globally-spanning meridional overturning circulation (MOC). However, convection is often highly localised in time and space, making it extremely difficult to accurately measure in field observations. Ocean models such as global circulation models (GCMs) are unable to resolve convection and turbulence and, instead, rely on simple convective parameterizations that result in a poor representation of convective processes and their impact on ocean circulation, air–sea exchange, and ocean biology. In the past few decades there has been markedly more observations, advancements in high-resolution numerical simulations, continued innovation in laboratory experiments and improvement of theory for ocean convection. The impacts of anthropogenic climate change on ocean convection are beginning to be observed, but key questions remain regarding future climate scenarios. Here, we review the current knowledge and future direction of ocean convection arising from sea–surface interactions, with a focus on mixed layer, open-ocean, and polynya convection.


Sign in / Sign up

Export Citation Format

Share Document