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1.
Marine cloud brightening (MCB) has been suggested as a possible solar radiation management approach to geoengineering the Earth’s climate in order to offset anthropogenic global warming. We discuss the utility of field experiments to test MCB. These experiments, if appropriately designed, would provide an unprecedented controlled environment to not only test MCB, but to understand aerosol impacts on climate. We discuss the science of MCB and review a set of field experiments that has been proposed as de minimis first steps to field test the concept. Our focus is upon issues of success determination, international oversight and/or governance, and outcomes if initial tests are deemed successful. 相似文献
2.
G. Bala Ken Caldeira Rama Nemani Long Cao George Ban-Weiss Ho-Jeong Shin 《Climate Dynamics》2011,37(5-6):915-931
Recent studies have shown that changes in solar radiation affect the hydrological cycle more strongly than equivalent CO2 changes for the same change in global mean surface temperature. Thus, solar radiation management ??geoengineering?? proposals to completely offset global mean temperature increases by reducing the amount of absorbed sunlight might be expected to slow the global water cycle and reduce runoff over land. However, proposed countering of global warming by increasing the albedo of marine clouds would reduce surface solar radiation only over the oceans. Here, for an idealized scenario, we analyze the response of temperature and the hydrological cycle to increased reflection by clouds over the ocean using an atmospheric general circulation model coupled to a mixed layer ocean model. When cloud droplets are reduced in size over all oceans uniformly to offset the temperature increase from a doubling of atmospheric CO2, the global-mean precipitation and evaporation decreases by about 1.3% but runoff over land increases by 7.5% primarily due to increases over tropical land. In the model, more reflective marine clouds cool the atmospheric column over ocean. The result is a sinking motion over oceans and upward motion over land. We attribute the increased runoff over land to this increased upward motion over land when marine clouds are made more reflective. Our results suggest that, in contrast to other proposals to increase planetary albedo, offsetting mean global warming by reducing marine cloud droplet size does not necessarily lead to a drying, on average, of the continents. However, we note that the changes in precipitation, evaporation and P-E are dominated by small but significant areas, and given the highly idealized nature of this study, a more thorough and broader assessment would be required for proposals of altering marine cloud properties on a large scale. 相似文献
3.
Wylie A. Carr Christopher J. Preston Laurie Yung Bronislaw Szerszynski David W. Keith Ashley M. Mercer 《Climatic change》2013,121(3):567-577
There have been a number of calls for public engagement in geoengineering in recent years. However, there has been limited discussion of why the public should have a say or what the public can be expected to contribute to geoengineering discussions. We explore how public engagement can contribute to the research, development, and governance of one branch of geoengineering, solar radiation management (SRM), in three key ways: 1. by fulfilling ethical requirements for the inclusion of affected parties in democratic decision making processes; 2. by contributing to improved dialogue and trust between scientists and the public; and 3. by ensuring that decisions about SRM research and possible deployment are informed by a broad set of societal interests, values, and framings. Finally, we argue that, despite the nascent state of many SRM technologies, the time is right for the public to participate in engagement processes. 相似文献
4.
A review of climate geoengineering proposals 总被引：2，自引：0，他引：2
Climate geoengineering proposals seek to rectify the current radiative imbalance via either (1) reducing incoming solar radiation (solar radiation management) or (2) removing CO2 from the atmosphere and transferring it to long-lived reservoirs (carbon dioxide removal). For each option, we discuss its effectiveness and potential side effects, also considering lifetime of effect, development and deployment timescale, reversibility, and failure risks. We present a detailed review that builds on earlier work by including the most recent literature, and is more extensive than previous comparative frameworks. Solar radiation management propsals are most effective but short-lived, whilst carbon dioxide removal measures gain effectiveness the longer they are pursued. Solar radiation management could restore the global radiative balance, but must be maintained to avoid abrupt warming, meanwhile ocean acidification and residual regional climate changes would still occur. Carbon dioxide removal involves less risk, and offers a way to return to a pre-industrial CO2 level and climate on a millennial timescale, but is potentially limited by the CO2 storage capacity of geological reservoirs. Geoengineering could complement mitigation, but it is not an alternative to it. We expand on the possible combinations of mitigation, carbon dioxide removal and solar radiation management that might be used to avoid dangerous climate change. 相似文献
5.
太阳是地球流体(大气和海洋等)运动的最终能量源,地球环境,尤其是气候的变化不能不与太阳活动有关.目前,普遍将全球增暖归结为温室气体含量增加所导致的温室效应的加剧,这无疑是有一定依据和有道理的.但从科学上来讲,人类活动所引起温室气体增加的影响,并非是唯一原因.基于已有的一些研究结果,从太阳活动的观点所进行的初步分析表明,太阳活动也可能是引起近世纪全球增暖的另一个重要原因.太阳活动的影响主要包括太阳辐射的直接影响和引发地磁场变化的间接影响两个方面,地球磁场的变化将可通过动力过程和热力过程而影响大气环流和气候的变化. 相似文献
6.
全球变暖趋缓研究进展 总被引：16，自引：5，他引：11
近十几年来,全球年平均表面温度上升趋势显示出停滞状态,即全球变暖趋缓,这引起了国际社会的广泛关注,同时也引发了对全球变暖的质疑,各国气候学家正努力就全球变暖趋缓的事实、原因及其可能影响展开研究。本文综述了目前国内外对全球变暖趋缓的研究结果。多数科学家认可近十几年来全球变暖停滞的事实,并认为太阳活动处于低位相、大气气溶胶（自然和人为）增加以及海洋吸收热量是变暖停滞的可能影响因子,其中海洋（尤其是700米以下的深海）对热量的储存可能是变暖停滞的关键。国际耦合模式比较计划第5阶段中的模式并未精确地描述各种有利降温影响因子的近期位相演变,因而其模拟的近期增暖趋势较观测偏强。由此推断,变暖停滞主要是自然因素造成的,并且预测变暖趋缓将在近几年或几十年内结束（依赖于太平洋年代际振荡的位相转变）,未来气温将仍主要受到温室气体增加的影响而表现出明显的上升趋势。因此,目前的全球变暖趋缓不大可能改变到本世纪末全球大幅度变暖带来的风险。本综述展望未来的研究热点包括:精确估算全球气温和海洋热含量的变率及其不确定性,海洋年代际信号（太平洋以及大西洋的年代际振荡）的转型机制,存储在深海的热量将在何时返回海洋表面及其对区域气候的潜在影响。 相似文献
7.
Research on geoengineering – deliberate management of the Earth’s climate system – is being increasingly discussed within the science and policy communities. While justified as necessary in order to expand the range of options available to policy makers in the future, geoengineering research has already engendered public controversy. Proposed projects have been protested or cancelled, and calls for a governance framework abound. In this paper, we consider the reasons why geoengineering research might be subject to additional governance and suggest mechanisms that might be usefully applied in developing such a framework. We consider criteria for governance as raised by a review of the growing literature on geoengineering and other controversial scientific topics. We suggest three families of concern that any governance research framework must respond to: the direct physical risks of the research; the transparency and responsibility in decision making for the research; and the larger societal meanings of the research. We review what mechanisms might be available to respond to these three families of concern, and consider how these might apply to geoengineering research. 相似文献
8.
Avoiding further aggravation of the consequences of global environmental change remains a complex governance challenge. Social relational structure among actors plays a key role for enhancing the capacity of collaborative approaches to environmental governance. We present an encompassing conceptual framework to advance understanding of the mechanisms that shape dynamics in environmental governance entities. Narrative theory is integrated with insights on group dynamics grounded in social network theory to contextualize local social complexities in governance processes. We assume that social relational structure between actors, and narrations they tell, co-produce narratives and dynamics at the group level. Three important mechanisms that influence dynamics are described: (1) the interplay between collaborative relationships and narrative congruence between individual actors, (2) the characteristics of actors, and (3) the actors’ embeddedness in the wider social structure. A set of testable hypotheses on the interplay between narration, narratives and social relational structure in environmental governance processes is presented. We conclude by discussing why we regard this framework useful to study local and regional governance entities in the context of addressing global environmental change. 相似文献
9.
Politicians who proclaim both their skepticism about global warming and their conservative religious credentials leave the impression that conservative Protestants may be more skeptical about scientists’ claims regarding global warming than others. The history of the relationship between conservative Protestantism and science on issues such as evolution also suggests that there may be increased skepticism. Analyzing the 2006 and 2010 General Social Survey, we find no evidence that conservative Protestantism leads respondents to have less belief in the conclusiveness of climate scientists’ claims. However, a second type of skepticism of climate scientists is an unwillingness to follow scientists’ public policy recommendations. We find that conservative Protestantism does lead to being less likely to want environmental scientists to influence the public policy debate about what to do about climate change. Existing sociological research on the relationship between religion and science suggests that this stance is due to a long-standing social/moral competition between conservative Protestantism and science. 相似文献
10.
More than one billion people worldwide receive cash or in-kind transfers from social protection programs. In low-income countries, these transfers are often conditioned on participation in labor-intensive public works to rehabilitate local infrastructure or natural resources. Despite their popularity, the environmental impacts of public works programs remain largely undocumented. We quantify the impact on tree cover of Ethiopia’s Productive Safety Net Program (PSNP), one of the world’s largest and longest-running public works programs, using satellite-based data of tree cover combined with difference-in-differences and inverse probability treatment weighting methodologies. We find that the PSNP increased tree cover by 3.8% between 2005 and 2019, with larger increases in less densely populated areas and on steep-sloped terrain. As increasing tree cover is considered an important strategy to mitigate global warming, our results suggest a win–win potential for social safety net programs with an environmental component. 相似文献
11.
Wally Broecker 《Climatic change》2017,142(1-2):1-6
Just over 40 years ago, I wrote a paper entitled “Climate change: Are we on the brink of a pronounced global warming?” In it, I attempted to explain why despite a rise in the atmosphere’s CO2 content there had been no significant warming. I predicted that a natural cooling was about to give way to a warming, and that industrial emissions of CO2 would amplify this warming. The paper published in Science in 1975. Warming did follow in 1976–1977. However, a retrospective look shows that my analysis was flawed. What is more—and to my chagrin—based on the words “global warming” in my Science paper, I was given the title “Father of Global Warming.” Not only did I not like this title, I had done little to merit it. 相似文献
12.
Public perceptions of climate change are traditionally measured through surveys. The exploding popularity of social networks, however, presents a new opportunity to research the spatiotemporal pattern of public discourse in relation to natural and/or socio-economic events. Among the social networks, Twitter is one of the largest microblogging services. The architecture of Twitter makes the question “what's happening?” the cornerstone of information exchange. This inspired the notion of using Twitter users as distributed sensors, which has been successfully employed in both the natural and social sciences. In 2012 and 2013, we collected 1.8 million tweets on “climate change” and “global warming” in five major languages (English, German, Russian, Portuguese, and Spanish). We discuss the geography of tweeting, weekly and daily patterns, major news events that affected tweeting on climate change, changes in the central topics of discussion over time, the most authoritative traditional media, blogging, and the most authoritative organizational sources of information on climate change referenced by Twitter users in different countries. We anticipate that social network mining will become a major source of data in the public discourse on climate change. 相似文献
13.
气候变化的归因与预估模拟研究 总被引：14，自引：2，他引：12
本文总结了近五年来中国科学院大气物理研究所在气候变暖的归因模拟与预估研究上的主要进展。研究表明,利用海温、太阳辐射和温室气体等实际强迫因子驱动大气环流模式,能够较为合理地模拟全球平均地表气温在20世纪的演变,但是难以模拟出包括北大西洋涛动／北极涛动和南极涛动在内的高纬度环流的长期变化趋势。利用温室气体和硫酸盐气溶胶等“历史资料”驱动气候系统模式,能够较好地模拟出20世纪后期的全球增暖,但如果要再现20世纪前期(1940年代)的变暖,还需同时考虑太阳辐射等自然外强迫因子。20世纪中国气温演变的耦合模式模拟技巧,较之全球平均情况要低;中国气候在1920年代的变暖机理目前尚不清楚。对于近50年中国东部地区“南冷北暖”、“南涝北旱”的气候变化,基于大气环流模式特别是区域气候模式的数值试验表明,夏季硫酸盐气溶胶的负辐射效应超过了温室气体的增暖效应,从而对变冷产生贡献。但现有的数值模拟证据,不足以说明气溶胶增加对“南涝北旱”型降水异常有贡献。20世纪中期以来,青藏高原主体存在明显增温趋势,温室气体浓度的增加对这种增暖有显著贡献。多模式集合预估的未来气候变化表明,21世纪全球平均温度将继续增暖,增温幅度因不同排放情景而异;中国大陆年均表面气温的增暖与全球同步,但增幅在东北、西部和华中地区较大,冬季升温幅度高于夏季、日最低温度升幅要强于日最高温度;全球增暖有可能对我国中东部植被的地理分布产生影响。伴随温室气体增加所导致的夏季平均温度升高,极端温度事件增多;在更暖的气候背景下,中国大部分地区总降水将增多,极端降水强度加大且更频繁发生,极端降水占总降水的比例也将增大。全球增暖有可能令大洋热盐环流减弱,但是减弱的幅度因模式而异。全球增暖可能不是导致北太平洋副热带－热带经圈环流自20世纪70年代以来变弱的原因。文章同时指出了模式预估结果中存在的不确定性。 相似文献
14.
Despite the observed increases in global average temperature, observations across the world show that the rate of pan evaporation at a regional scale has been steadily decreasing over the past 50 years. This is known as the pan evaporation paradox. This paper reviews current reported pan evaporation trends, examines available theoretical explanations about this “paradox”, and discusses current research gaps and priorities. It concludes that: (1) three major potential causes of pan evaporation, solar radiation, vapour pressure deficit (VPD) and wind speed, have been changing in the last 50 years. The magnitude of changes and importance of each of these three causes varies from region to region, as does the pan evaporation trend, although overall there is a decreasing trend. (2) Currently two existing theories explaining the pan evaporation trends have limits and are only valid in some specific regions and seasons. Neither of them provides a fundamental physical-based theory that could be applied everywhere. (3) Further investigations are needed before we can fully understand the global evapotranspiration trend in global warming scenarios. 相似文献
15.
Globalization has increased the speed and flow of people, information, and commodities across space, integrating markets and increasing interdependence of geographically dispersed places worldwide. Places historically driven by largely local forces and market demands are now increasingly affected by drivers at multiple scales. Trade is particularly important in driving these changes and more fish is now exported to international markets than ever before. When small-scale fisheries are integrated into global markets, local social–ecological systems change with potentially both positive and negative impacts on livelihoods, economics and ecology, but few studies systematically investigate how and why the outcomes of market integration vary from case to case.This paper systematically assesses multiple (social, ecological, economic and institutional) local effects of market integration in cases around the world by drawing on the global environmental change syndromes approach. Furthermore, we examine the factors contributing to the syndromes observed. Our analysis identifies three distinct social–ecological syndromes associated with international seafood trade. Results suggest that the presence of strong and well-enforced institutions is the principal factor behind the syndrome characterized by sustained fish stocks, while a combination of weak institutions, patron–client relationships, high demand from China and highly vulnerable target species explain the other two syndromes distinguished by declining stocks, conflict and debt among fishers.A key finding is that the factors emerging as important for explaining the different syndromes derive from different scales (e.g. local market structures vs distant market characteristics), indicating a need for multi-level governance approaches to deal with the effects of market integration. Furthermore, the meta-analysis shows that each syndrome encompasses fisheries from multiple continents. This suggests that the increasingly global nature of the seafood trade appears to be driving local dynamics by creating similar conditions for vulnerabilities in localities around the world, lending support to the notion of tele-connectivity across geographic space. 相似文献
16.
We analyse Japanese newspaper coverage of global warming from January 1998 to July 2007 and how public opinion during parts of that period were influenced by newspaper coverage. We show that a dramatic increase in newspaper coverage of global warming from January 2007 correlated with an increase in public concern for the issue. Before January 2007, we find that coverage of global warming had an immediate but short-term influence on public concern. With such transitory high levels of media coverage we suggest that for more effective communication of climate change, strategies aimed at maintaining mass-media coverage of global warming are required. 相似文献
17.
The sensitivity of the global climate is essentially determined by the radiative damping of the global mean surface temperature
anomaly through the outgoing radiation from the top of the atmosphere (TOA). Using the TOA fluxes of terrestrial and reflected
solar radiation obtained from the Earth radiation budget experiment (ERBE), this study estimates the magnitude of the overall
feedback, which modifies the radiative damping of the annual variation of the global mean surface temperature, and compare
it with model simulations. Although the pattern of the annually varying anomaly is quite different from that of the global
warming, the analysis conducted here may be used for assessing the systematic bias of the feedback that operates on the CO2-induced warming of the surface temperature. In the absence of feedback effect, the outgoing terrestrial radiation at the
TOA is approximately follows the Stefan-Boltzmann’s fourth power of the planetary emission temperature. However, it deviates
significantly from the blackbody radiation due to various feedbacks involving water vapor and cloud cover. In addition, the
reflected solar radiation is altered by the feedbacks involving sea ice, snow and cloud, thereby affecting the radiative damping
of surface temperature. The analysis of ERBE reveals that the radiative damping is weakened by as much as 70% due to the overall
effect of feedbacks, and is only 30% of what is expected for the blackbody with the planetary emission temperature. Similar
feedback analysis is conducted for three general circulation models of the atmosphere, which was used for the study of cloud
feedback in the preceding study. The sign and magnitude of the overall feedback in the three models are similar to those of
the observed. However, when it is subdivided into solar and terrestrial components, they are quite different from the observation
mainly due to the failure of the models to simulate individually the solar and terrestrial components of the cloud feedback.
It is therefore desirable to make the similar comparison not only for the overall feedback but also for its individual components
such as albedo- and cloud-feedbacks. Although the pattern of the annually-varying anomaly is quite different from that of
global warming, the methodology of the comparative analysis presented here may be used for the identification of the systematic
bias of the overall feedback in a model. A proposal is made for the estimation of the best guess value of climate sensitivity
using the outputs from many climate models submitted to the Intergovernmental panel on Climate Change. 相似文献
18.
黑碳气溶胶能吸收从可见光到红外波段的太阳辐射,已经被部分研究认为是造成全球变暖的一个潜在因子。黑碳气溶胶既可以通过直接气候效应改变地-气系统的辐射平衡,又可以作为云凝结核或冰核改变云的微物理特性,间接影响区域或全球气候。对黑碳气溶胶的辐射强迫及其气候效应的研究现状进行总结和分析后,指出了目前黑碳气溶胶气候效应研究中存在的不确定性,并对未来的相关研究提出了一些建议。 相似文献
19.
Experience-Based and Description-Based Perceptions of Long-Term Risk: Why Global Warming does not Scare us (Yet) 总被引：3，自引：2，他引：3
Elke U. Weber 《Climatic change》2006,77(1-2):103-120
20.
The future climate change projections are essentially based on coupled general circulation model (CGCM) simulations, which give a distinct global warming pattern with arctic winter amplification, an equilibrium land-sea warming contrast and an inter-hemispheric warming gradient. While these simulations are the most important tool of the Intergovernmental Panel on Climate Change (IPCC) predictions, the conceptual understanding of these predicted structures of climate change and the causes of their uncertainties is very difficult to reach if only based on these highly complex CGCM simulations. In the study presented here we will introduce a very simple, globally resolved energy balance (GREB) model, which is capable of simulating the main characteristics of global warming. The model shall give a bridge between the strongly simplified energy balance models and the fully coupled 4-dimensional complex CGCMs. It provides a fast tool for the conceptual understanding and development of hypotheses for climate change studies, which shall build a basis or starting point for more detailed studies of observations and CGCM simulations. It is based on the surface energy balance by very simple representations of solar and thermal radiation, the atmospheric hydrological cycle, sensible turbulent heat flux, transport by the mean atmospheric circulation and heat exchange with the deeper ocean. Despite some limitations in the representations of the basic processes, the models climate sensitivity and the spatial structure of the warming pattern are within the uncertainties of the IPCC models simulations. It is capable of simulating aspects of the arctic winter amplification, the equilibrium land-sea warming contrast and the inter-hemispheric warming gradient with good agreement to the IPCC models in amplitude and structure. The results give some insight into the understanding of the land-sea contrast and the polar amplification. The GREB model suggests that the regional inhomogeneous distribution of atmospheric water vapor and the non-linear sensitivity of the downward thermal radiation to changes in the atmospheric water vapor concentration partly cause the land-sea contrast and may also contribute to the polar amplification. The combination of these characteristics causes, in general, dry and cold regions to warm more than other regions. 相似文献