Diversity,competition, extinction: the ecophysics of language change

As indicated early by Charles Darwin, languages behave and change very much like living species. They display high diversity, differentiate in space and time, emerge and disappear. A large body of literature has explored the role of information exchanges and communicative constraints in groups of agents under selective scenarios. These models have been very helpful in providing a rationale on how complex forms of communication emerge under evolutionary pressures. However, other patterns of large-scale organization can be described using mathematical methods ignoring communicative traits. These approaches consider shorter time scales and have been developed by exploiting both theoretical ecology and statistical physics methods. The models are reviewed here and include extinction, invasion, origination, spatial organization, coexistence and diversity as key concepts and are very simple in their defining rules. Such simplicity is used in order to catch the most fundamental laws of organization and those universal ingredients responsible for qualitative traits. The similarities between observed and predicted patterns indicate that an ecological theory of language is emerging, supporting (on a quantitative basis) its ecological nature, although key differences are also present. Here, we critically review some recent advances and outline their implications and limitations as well as highlight problems for future research.     

Oil shortages, climate change and collective action

Concerns over future oil scarcity might not be so worrying but for the high carbon content of substitutes, and the limited capacity of the atmosphere to absorb additional CO(2) from burning fuel. The paper argues that the tools of economics are helpful in understanding some of the key issues in pricing fossil fuels, the extent to which pricing can be left to markets, the need for, and design of, international agreements on corrective carbon pricing, and the potential Prisoners' Dilemma in reaching such agreements, partly mitigated in the case of oil by current taxes and the probable incidence of carbon taxes on the oil price. The 'Green Paradox', in which carbon pricing exacerbates climate change, is theoretically possible, but empirically unlikely.     

积极应对气候变化 履行企业社会责任——洛阳北方企业集团有限公司主动开展温室气体核查项目纪实

当前,应对气候变化已经是摆在世界各国政府日常工作和国际会议议程中的重要议题,低碳经济也已成为世界主要国家统筹经济、社会和自然和谐发展,保护全球气候环境的战略选择。2010年8月,国家发改委宣布首先在全国五省八市开展低碳省区、低碳城市试点工作;     

Spatial planning and climate change

Wind energy development is expanding. Preparations for wind farms include environmental impact assessments, specifically with visual impact assessments (VIAs). Often using simulated photographs, VIAs depict the post-development landscape appearance with new wind energy structures. This Ontario case study compares simulated photographs submitted as part of a VIA with post-development conditions. Simulations were judged for accuracy in turbine number, height, diameter, and location, and adequacy in representation of built conditions. Simulations were partially representative of postdevelopment conditions, yet commonly under-represented turbine number and size in different locations than they were built. Simulation frames were too narrow to adequately represent human vision and simulations under-estimated how many wind turbines were visible from a single landscape position. Outcomes suggest that visual simulations can lack accuracy or representativeness, misleading the public. Adopting province-wide VIA criteria and increasing adherence to visual simulation guidance may be necessary to improve the accuracy and representativeness of VIA content.     

Solar variability,coupling between atmospheric layers and climate change

One of the enduring puzzles of atmospheric physics is the extent to which changes in the Sun can influence the behaviour of the climate system. While solar-flux changes tend to be relatively modest, a number of observations of atmospheric parameters indicates a disproportionately large response. Global-scale models of the coupled middle and upper atmosphere have provided new insights into some of the mechanisms that may be responsible for the amplification of the solar signal. In particular, modification of the transport of heat and chemicals such as ozone by waves during periods of solar activity has been shown to make an important contribution to the climate of the stratosphere and mesosphere. In this paper, a review of some of the recent advances in understanding the coupling between atmospheric layers and how this work relates to Sun-weather relations and climate change in the troposphere will be presented, along with a discussion of some of the challenges that remain.     

Adaptation,flexibility and project decision-making with climate change uncertainties

Project planning in the future must directly address both climate change and uncertainties about it. This paper presents the use of classical decision criteria, such as maximin and minimax regret, and approaches for adapting to climate change given the uncertainties. Adaptation strategies can help reduce the effects of uncertainties by allowing for adjustments in designs as the future climate evolves, although at a cost for such future flexibility. Adding such options and evaluating them against other design options using the decision criteria can provide valuable information to decision-makers and other stakeholders during project planning. A hypothetical example of a hydroelectric project illustrates the use of these approaches.     

Sea-ice switches and abrupt climate change

We propose that past abrupt climate changes were probably a result of rapid and extensive variations in sea-ice cover. We explain why this seems a perhaps more likely explanation than a purely thermohaline circulation mechanism. We emphasize that because of the significant influence of sea ice on the climate system, it seems that high priority should be given to developing ways for reconstructing high-resolution (in space and time) sea-ice extent for past climate-change events. If proxy data can confirm that sea ice was indeed the major player in past abrupt climate-change events, it seems less likely that such dramatic abrupt changes will occur due to global warming, when extensive sea-ice cover will not be present.     

Global climate change and hydroelectric resources

Hydroelectric power is one of the most widely exploited forms of renewable energy and, in areas where global climate change (GCC) causes precipitation characteristics to change significantly, or more importantly, where run off is reduced, existing hydroelectric installations may require replacement with alternative sources of power. As economic appraisals of new hydroelectric projects are normally made on a long-term basis, GCC may also necessitate revision of assessments of unexploited hydroelectric potential. This paper considers two geographic regions where significant climate change may occur and assesses how possible future precipitation distribution and water run-off may affect the viability of hydroelectric power     

The runaway greenhouse: implications for future climate change, geoengineering and planetary atmospheres

The ultimate climate emergency is a 'runaway greenhouse': a hot and water-vapour-rich atmosphere limits the emission of thermal radiation to space, causing runaway warming. Warming ceases only after the surface reaches approximately 1400 K and emits radiation in the near-infrared, where water is not a good greenhouse gas. This would evaporate the entire ocean and exterminate all planetary life. Venus experienced a runaway greenhouse in the past, and we expect that the Earth will in around 2 billion years as solar luminosity increases. But could we bring on such a catastrophe prematurely, by our current climate-altering activities? Here, we review what is known about the runaway greenhouse to answer this question, describing the various limits on outgoing radiation and how climate will evolve between these. The good news is that almost all lines of evidence lead us to believe that is unlikely to be possible, even in principle, to trigger full a runaway greenhouse by addition of non-condensible greenhouse gases such as carbon dioxide to the atmosphere. However, our understanding of the dynamics, thermodynamics, radiative transfer and cloud physics of hot and steamy atmospheres is weak. We cannot therefore completely rule out the possibility that human actions might cause a transition, if not to full runaway, then at least to a much warmer climate state than the present one. High climate sensitivity might provide a warning. If we, or more likely our remote descendants, are threatened with a runaway greenhouse, then geoengineering to reflect sunlight might be life's only hope. Injecting reflective aerosols into the stratosphere would be too short-lived, and even sunshades in space might require excessive maintenance. In the distant future, modifying Earth's orbit might provide a sustainable solution. The runaway greenhouse also remains relevant in planetary sciences and astrobiology: as extrasolar planets smaller and nearer to their stars are detected, some will be in a runaway greenhouse state.     

Modelling climate change: the role of unresolved processes

Our understanding of the climate system has been revolutionized recently, by the development of sophisticated computer models. The predictions of such models are used to formulate international protocols, intended to mitigate the severity of global warming and its impacts. Yet, these models are not perfect representations of reality, because they remove from explicit consideration many physical processes which are known to be key aspects of the climate system, but which are too small or fast to be modelled. The purpose of this paper is to give a personal perspective of the current state of knowledge regarding the problem of unresolved scales in climate models. A recent novel solution to the problem is discussed, in which it is proposed, somewhat counter-intuitively, that the performance of models may be improved by adding random noise to represent the unresolved processes.     

Regional climate change mitigation with crops: context and assessment

The intention of this review is to place crop albedo biogeoengineering in the wider picture of climate manipulation. Crop biogeoengineering is considered within the context of the long-term modification of the land surface for agriculture over several thousand years. Biogeoengineering is also critiqued in relation to other geoengineering schemes in terms of mitigation power and adherence to social principles for geoengineering. Although its impact is small and regional, crop biogeoengineering could be a useful and inexpensive component of an ensemble of geoengineering schemes to provide temperature mitigation. The method should not detrimentally affect food security and there may even be positive impacts on crop productivity, although more laboratory and field research is required in this area to understand the underlying mechanisms.     

The economics of abrupt climate change

The US National Research Council defines abrupt climate change as a change of state that is sufficiently rapid and sufficiently widespread in its effects that economies are unprepared or incapable of adapting. This may be too restrictive a definition, but abrupt climate change does have implications for the choice between the main response options: mitigation (which reduces the risks of climate change) and adaptation (which reduces the costs of climate change). The paper argues that by (i) increasing the costs of change and the potential growth of consumption, and (ii) reducing the time to change, abrupt climate change favours mitigation over adaptation. Furthermore, because the implications of change are fundamentally uncertain and potentially very high, it favours a precautionary approach in which mitigation buys time for learning. Adaptation-oriented decision tools, such as scenario planning, are inappropriate in these circumstances. Hence learning implies the use of probabilistic models that include socioeconomic feedbacks.     

The fluvial record of climate change

Fluvial landforms and sediments can be used to reconstruct past hydrological conditions over different time scales once allowance has been made for tectonic, base-level and human complications. Field stratigraphic evidence is explored here at three time scales: the later Pleistocene, the Holocene, and the historical and instrumental period. New data from a range of field studies demonstrate that Croll-Milankovitch forcing, Dansgaard-Oeschger and Heinrich events, enhanced monsoon circulation, millennial- to centennial-scale climate variability within the Holocene (probably associated with solar forcing and deep ocean circulation) and flood-event variability in recent centuries can all be discerned in the fluvial record. Although very significant advances have been made in river system and climate change research in recent years, the potential of fluvial palaeohydrology has yet to be fully realized, to the detriment of climatology, public health, resource management and river engineering.     

Rapid climate change: scientific challenges and the new NERC programme

In this paper the scientific challenges of observing, modelling, understanding and predicting rapid changes in climate are discussed, with a specific focus on the role of the Atlantic thermohaline circulation. The palaeo and present-day observational and modelling studies being carried out to meet these challenges, under the aegis of a new NERC Rapid Climate Change thematic programme (RAPID), are outlined. In particular, the paper describes the work being done to monitor changes in the meridional overturning circulation of the North Atlantic. The paper concludes with some speculative comments about potential mechanisms for rapid changes.     

Containing the risk of catastrophic climate change

Clean Technologies and Environmental Policy - There is a general perception that limiting emissions of carbon dioxide will be sufficient to avoid catastrophic climate change. The reality could well...     

Ensembles and probabilities: a new era in the prediction of climate change

Predictions of future climate are of central importance in determining actions to adapt to the impacts of climate change and in formulating targets to reduce emissions of greenhouse gases. In the absence of analogues of the future, physically based numerical climate models must be used to make predictions. New approaches are under development to deal with a number of sources of uncertainty that arise in the prediction process. This paper introduces some of the concepts and issues in these new approaches, which are discussed in more detail in the papers contained in this issue.     

标准化面临气候变化的挑战——俄通过度量衡和标准化手段测量人类活动对环境的影响

本文介绍了俄罗斯为应对气候变化在保护自然资源方面出台的系列标准,指出必须提高测量准确性,减少测量误差,以减少生态危害。