A comparison of statistical downscaling and climate change factor methods: impacts on low flows in the River Thames, United Kingdom

Strategic-scale assessments of climate change impacts are often undertaken using the change factor (CF) methodology whereby future changes in climate projected by General Circulation Models (GCMs) are applied to a baseline climatology. Alternatively, statistical downscaling (SD) methods apply climate variables from GCMs to statistical transfer functions to estimate point-scale meteorological series. This paper explores the relative merits of the CF and SD methods using a case study of low flows in the River Thames under baseline (1961–1990) and climate change conditions (centred on the 2020s, 2050s and 2080s). Archived model outputs for the UK Climate Impacts Programme (UKCIP02) scenarios are used to generate daily precipitation and potential evaporation (PE) for two climate change scenarios via the CF and SD methods. Both signal substantial reductions in summer precipitation accompanied by increased PE throughout the year, leading to reduced flows in the Thames in late summer and autumn. However, changes in flow associated with the SD scenarios are generally more conservative and complex than that arising from CFs. These departures are explained in terms of the different treatment of multidecadal natural variability, temporal structuring of daily climate variables and large-scale forcing of local precipitation and PE by the two downscaling methods.     

Some effects of deforestation on nocturnal drainage flow and local climate — A numerical study

The three-dimensional mesoscale model FITNAH has been modified to simulate effects of a tall tree canopy on airflow in complex terrain. Numerical experiments show the general features of meteorological variables inside a plant stand with low wind speeds and a nearly neutral thermal stratification during night. Available observations from the Finkenbach valley and the simulated temperatures near the ground show good agreeement.Comparison of model results for a nighttime situation for cases with and without a canopy (after complete deforestation) leads to the main results, viz., that surface wind speed will increase and the atmosphere near the ground will become colder after deforestation.However, the production rate of cooled air (expressed in m³m^–2h^–1) decreases; that means that forested slopes are more effective in ventilating a city than slopes covered with short vegetation.     

Cultural impacts to tribes from climate change influences on forests

Climate change related impacts, such as increased frequency and intensity of wildfires, higher temperatures, extreme changes to ecosystem processes, forest conversion and habitat degradation are threatening tribal access to valued resources. Climate change is and will affect the quantity and quality of resources tribes depend upon to perpetuate their cultures and livelihoods. Climate impacts on forests are expected to directly affect culturally important fungi, plant and animal species, in turn affecting tribal sovereignty, culture, and economy. This article examines the climate impacts on forests and the resulting effects on tribal cultures and resources. To understand potential adaptive strategies to climate change, the article also explores traditional ecological knowledge and historical tribal adaptive approaches in resource management, and contemporary examples of research and tribal practices related to forestry, invasive species, traditional use of fire and tribal-federal coordination on resource management projects. The article concludes by summarizing tribal adaptive strategies to climate change and considerations for strengthening the federal-tribal relationship to address climate change impacts to forests and tribal valued resources.     

The quiet opposition: How the pro-economy lobby influences climate policy

The lack of ambitious climate change policies in large anglophone countries, such as the United States, has been explained by the strong media presence of denialist arguments against climate science. Such counterarguments are less visible in the news media of most European countries. Why do many of these countries nevertheless fail to enact ambitious climate change policies? This paper suggests that influential organizations may block ambitious climate change policies in corporatist countries without an extensive media strategy or a strong denialist message. We draw from theories on the policy process, policy networks, influence strategies, and comparative politics to formulate hypotheses about the existence, influence, and strategies of organizations that oppose ambitious climate policy. We test these hypotheses using an original combination of media data and survey data on the national climate policy network in Finland, a corporatist European country that has long lacked ambitious climate policies. The findings show that a coalition that prioritizes economic competitiveness over climate change mitigation is influential and occupies a central position in the policy network. This pro-economy lobby does not question the validity of climate science or actively seek media visibility. Rather, it influences the policy process using other strategies, such as inside lobbying, and appears in the news media less often than other climate policy organizations. Our results suggest that opponents of climate change mitigation can be powerful despite a weak media presence. This implies that studies on climate politics should pay more attention to strategies of influencing beyond the media spotlight.     

Overcoming skepticism with education: interacting influences of worldview and climate change knowledge on perceived climate change risk among adolescents

Though many climate literacy efforts attempt to communicate climate change as a risk, these strategies may be ineffective because among adults, worldview rather than scientific understanding largely drives climate change risk perceptions. Further, increased science literacy may polarize worldview-driven perceptions, making some climate literacy efforts ineffective among skeptics. Because worldviews are still forming in the teenage years, adolescents may represent a more receptive audience. This study examined how worldview and climate change knowledge related to acceptance of anthropogenic global warming (AGW) and in turn, climate change risk perception among middle school students in North Carolina, USA (n?=?387). We found respondents with individualistic worldviews were 16.1 percentage points less likely to accept AGW than communitarian respondents at median knowledge levels, mirroring findings in similar studies among adults. The interaction between knowledge and worldview, however, was opposite from previous studies among adults, because increased climate change knowledge was positively related to acceptance of AGW among both groups, and had a stronger positive relationship among individualists. Though individualists were 24.1 percentage points less likely to accept AGW than communitarians at low levels (bottom decile) of climate change knowledge, there was no statistical difference in acceptance levels between individualists and communitarians at high levels of knowledge (top decile). Non-White and females also demonstrated higher levels of AGW acceptance and climate change risk perception, respectively. Thus, education efforts specific to climate change may counteract divisions based on worldviews among adolescents.     

Impact of a climate network: The role of intermediaries in local level climate action

Local governments have set highly ambitious greenhouse gas emission reduction targets on a strategic level, in some cases influenced by intermediary networks. Yet, the quantitative impacts of climate strategies or the sharing of best practices on emissions still remain largely unknown. The aim of this study was to examine the impact of an intermediary network on municipal greenhouse gas emissions. This was done through an econometric analysis of the emissions of municipalities that are members of the Finnish Hinku (Towards Carbon Neutral Municipalities) network, and through comprehensive qualitative interviews conducted in 40 of those municipalities. Our quantitative results show that Hinku network membership has successfully led to the lowering of greenhouse gas emission levels in participating municipalities. The qualitative interviews suggest that this is due to systematic local level climate work, enhanced by network membership. The network functions as an intermediary in two ways: by providing expertise and enabling peer-support. In addition, it has also succeeded in legitimising local level climate action. Ambitious local level climate action can also affect the ambition of national climate policy, which in turn may reflect on the amount resources allocated to local climate action.     

Pacific and Atlantic influences on Mesoamerican climate over the past millennium

A new tree-ring reconstruction of the Palmer Drought Severity Index (PDSI) for Mesoamerica from AD 771 to 2008 identifies megadroughts more severe and sustained than any witnessed during the twentieth century. Correlation analyses indicate strong forcing of instrumental and reconstructed June PDSI over Mesoamerica from the El Ni?o/Southern Oscillation (ENSO). Spectral analyses of the 1,238-year reconstruction indicate significant concentrations of variance at ENSO, sub-decadal, bi-decadal, and multidecadal timescales. Instrumental and model-based analyses indicate that the Atlantic Multidecadal Oscillation is important to warm season climate variability over Mexico. Ocean-atmospheric variability in the Atlantic is not strongly correlated with the June PDSI reconstruction during the instrumental era, but may be responsible for the strong multidecadal variance detected in the reconstruction episodically over the past millennium. June drought indices in Mesoamerica are negatively correlated with gridded June PDSI over the United States from 1950 to 2005, based on both instrumental and reconstructed data. Interannual variability in this latitudinal moisture gradient is due in part to ENSO forcing, where warm events favor wet June PDSI conditions over the southern US and northern Mexico, but dryness over central and southern Mexico (Mesoamerica). Strong anti-phasing between multidecadal regimes of tree-ring reconstructed June PDSI over Mesoamerica and reconstructed summer (JJA) PDSI over the Southwest has also been detected episodically over the past millennium, including the 1950–1960s when La Ni?a and warm Atlantic SSTs prevailed, and the 1980–1990s when El Ni?o and cold Atlantic SSTs prevailed. Several Mesoamerican megadroughts are reconstructed when wetness prevailed over the Southwest, including the early tenth century Terminal Classic Drought, implicating El Ni?o and Atlantic SSTs in this intense and widespread drought that may have contributed to social changes in ancient Mexico.     

Direct and semi-direct radiative effects of anthropogenic aerosols in the Western United States: Seasonal and geographical variations according to regional climate characteristics

The direct and semi-direct radiative effects of anthropogenic aerosols on the radiative transfer and cloud fields in the Western United States (WUS) according to seasonal aerosol optical depth (AOD) and regional climate are examined using a regional climate model (RCM) in conjunction with the aerosol fields from a GEOS-Chem chemical-transport model (CTM) simulation. The two radiative effects cannot be separated within the experimental design in this study, thus the combined direct- and semi-direct effects are called radiative effects hereafter. The CTM shows that the AOD associated with the anthropogenic aerosols is chiefly due to sulfates with minor contributions from black carbon (BC) and that the AOD of the anthropogenic aerosol varies according to local emissions and the seasonal low-level winds. The RCM-simulated anthropogenic aerosol radiative effects vary according to the characteristics of regional climate, in addition to the AOD. The effects on the top of the atmosphere (TOA) outgoing shortwave radiation (OSRT) range from ?0.2?Wm^?2 to ?1?Wm^?2. In Northwestern US (NWUS), the maximum and minimum impact of anthropogenic aerosols on OSRT occurs in summer and winter, respectively, following the seasonal AOD. In Arizona-New Mexico (AZNM), the effect of anthropogenic sulfates on OSRT shows a bimodal distribution with winter/summer minima and spring/fall maxima, while the effect of anthropogenic BC shows a single peak in summer. The anthropogenic aerosols affect surface insolation range from ?0.6?Wm^?2 to ?2.4?Wm^?2, with similar variations found for the effects on OSRT except that the radiative effects of anthropogenic BC over AZNM show a bimodal distribution with spring/fall maxima and summer/winter minima. The radiative effects of anthropogenic sulfates on TOA outgoing longwave radiation (OLR) and the surface downward longwave radiation (DLRS) are notable only in summer and are characterized by strong geographical contrasts; the summer OLR in NWUS (AZNM) is reduced (enhanced) by 0.52?Wm^?2 (1.14?Wm^?2). The anthropogenic sulfates enhance (reduce) summer DLRS by 0.2?Wm^?2 (0.65?Wm^?2) in NWUS (AZNM). The anthropogenic BC affect DLRS noticeably only in AZNM during summer. The anthropogenic aerosols affect the cloud water path (CWP) and the radiative transfer noticeably only in summer when convective clouds are dominant. Primarily shortwave-reflecting anthropogenic sulfates decrease and increase CWP in AZNM and NWUS, respectively, however, the shortwave-absorbing anthropogenic BC reduces CWP in both regions. Due to strong feedback via convective clouds, the radiative effects of anthropogenic aerosols on the summer radiation field are more closely correlated with the changes in CWP than the AOD. The radiative effect of the total anthropogenic aerosols is dominated by the anthropogenic sulfates that contribute more than 80% of the total AOD associated with the anthropogenic aerosols.     

Spatial modelling of summer climate indices based on local climate zones: expected changes in the future climate of Brno,Czech Republic

Climatic Change - With global climate change ongoing, there is growing concern about future living conditions in urban areas. This contribution presents the modelled spatial distribution of two...     

Farmer perceptions of climate change: Associations with observed temperature and precipitation trends,irrigation, and climate beliefs

How individuals perceive climate change is linked to whether individuals support climate policies and whether they alter their own climate-related behaviors, yet climate perceptions may be influenced by many factors beyond local shifts in weather. Infrastructure designed to control or regulate natural resources may serve as an important lens through which people experience climate, and thus may influence perceptions. Likewise, perceptions may be influenced by personal beliefs about climate change and whether it is human-induced. Here we examine farmer perceptions of historical climate change, how perceptions are related to observed trends in regional climate, how perceptions are related to the presence of irrigation infrastructure, and how perceptions are related to beliefs and concerns about climate change. We focus on the regions of Marlborough and Hawke’s Bay in New Zealand, where irrigation is utilized on the majority of cropland. Data are obtained through analysis of historical climate records from local weather stations, interviews (n = 20), and a farmer survey (n = 490). Across both regions, no significant historical trends in annual precipitation and summer temperatures since 1980 are observed, but winter warming trends are significant at around 0.2–0.3 °C per decade. A large fraction of farmers perceived increases in annual rainfall despite instrumental records indicating no significant trends, a finding that may be related to greater perceived water availability associated with irrigation growth. A greater fraction of farmers perceived rainfall increases in Marlborough, where irrigation growth has been most substantial. We find those classes of farmers more likely to have irrigation were also significantly more likely to perceive an increase in annual rainfall. Furthermore, we demonstrate that perceptions of changing climate – regardless of their accuracy – are correlated with increased belief in climate change and an increased concern for future climate impacts. Those farmers that believe climate change is occurring and is human induced are more likely to perceive temperature increases than farmers who believe climate change is not occurring and is not human induced. These results suggest that perceptions are influenced by a variety of personal and environmental factors, including infrastructure, which may in turn alter decisions about climate adaptation.     

Changes in the occurrence of storm surges around the United Kingdom under a future climate scenario using a dynamic storm surge model driven by the Hadley Centre climate models

 A potential consequence of climate change is an alteration of the frequency of extreme coastal storm surge events. It is these extreme events which, from an impacts point of view, will be of more concern than the slow inundation of coastal areas by century scale changes in mean sea level. In this study, a 35 km resolution storm surge model of the North west European continental shelf region has been driven by winds and pressures from the Hadley Centre nested regional climate model. Simulations of both present day and future climate (the end of the twentyfirst century) have been performed. The results suggest that, in addition to the effect of rising mean sea level, at many locations around the United Kingdom coastline future changes in local meteorology will lead to further significant changes in the return periods of extreme storm surge events. At most sites, this meteorologically forced change represents a reduction in return period. Received: 18 September 2000 / Accepted: 8 February 2001     

甘肃河西日光温棚黄瓜小气候适应性分析

通过试验分析 ,河西日光温棚可充分利用晚秋、早春的气候资源 ,提高资源转换率 ,用灰色理论计算 ,温棚黄瓜生物量与棚内小气候条件有较好的关联度 ,其中影响黄瓜生长的主导因子是热量 ,其次是空气湿度     

乌鲁木齐城市化进程对局地气候变化的影响研究

利用1976—2014年乌鲁木齐城区和郊区两个气象站的气温、降水、相对湿度和风速气象数据及1995—2014年乌鲁木齐市城市发展数据,运用线性趋势对比分析城区和郊区各气候要素的年际变化特征;采用相关分析法对城市化因子和气候要素进行了探讨。结果表明:城、郊区气温均呈明显的上升趋势,城区的年均气温高于郊区;城区降水量是郊区的3.93倍,增长速率是郊区的3.98倍;各年代城区相对湿度比郊区大,但呈下降趋势,郊区呈上升趋势;各年代郊区风速大于城区,郊区风速约为城区的2.35倍,均呈下降趋势。近20 a,乌鲁木齐城市化进程加快,对局地气候影响明显,其中对平均气温和相对湿度的影响最为显著。     

Influence of non-feedback variations of radiation on the determination of climate feedback

Recent studies have estimated the magnitude of climate feedback based on the correlation between time variations in outgoing radiation flux and sea surface temperature (SST). This study investigates the influence of the natural non-feedback variation (noise) of the flux occurring independently of SST on the determination of climate feedback. The observed global monthly radiation flux is used from the Clouds and the Earth's Radiant Energy System (CERES) for the period 2000–2008. In the observations, the time lag correlation of radiation and SST shows a distorted curve with low statistical significance for shortwave radiation while a significant maximum at zero lag for longwave radiation over the tropics. This observational feature is explained by simulations with an idealized energy balance model where we see that the non-feedback variation plays the most significant role in distorting the curve in the lagged correlation graph, thus obscuring the exact value of climate feedback. We also demonstrate that the climate feedback from the tropical longwave radiation in the CERES data is not significantly affected by the noise. We further estimate the standard deviation of radiative forcings (mainly from the noise) relative to that of the non-radiative forcings, i.e., the noise level from the observations and atmosphere–ocean coupled climate model simulations in the framework of the simple model. The estimated noise levels in both CERES (>13 %) and climate models (11–28 %) are found to be far above the critical level (~5 %) that begins to misrepresent climate feedback.     

Overcoming cross-scale challenges to climate change adaptation for local government: a focus on Australia

This paper aims to identify key cross-scale challenges to planned adaptation within the context of local government in Australia, and suggest enabling actions to overcome such challenges. Many of the impacts of climate change and variability have or will be experienced at the local level. Local governments are embedded in a larger governance context that has the potential to limit the effectiveness of planned adaptation initiatives on the ground. This study argues that research on constraints and barriers to adaptation must place greater attention to understanding the broader multi-governance system and cross-scale constraints that shape adaptation at the local government scale. The study identified seven key enabling actions for overcoming cross-scale challenges faced by local governments in Australia when undertaking climate change adaptation planning and implementation. A central conclusion of this study is that a cooperative and collaborative approach is needed where joint recognition of the scale of the issue and its inherent cross-scale complexities are realised. Many of the barriers or constraints to adaptation planning are interlinked, requiring a whole government approach to adaptation planning. The research suggests a stronger role at the state and national level is required for adaptation to be facilitated and supported at the local level.     

Validation of present-day regional climate simulations over Europe: LAM simulations with observed boundary conditions

 Nested limited-area modelling is one method of down-scaling general circulation model (GCM) climate change simulations. To give credibility to this method the nested limited-area model (LAM) must be shown to simulate local present-day climate conditions fairly accurately. Here seven different European limited-area models driven by observed boundary conditions (operational weather forecast analyses) are validated against observations, and inter-compared for summer and winter months. Relatively large biases are found. In summer large positive surface air temperature biases are found over southeast Europe. The main reason is deficiencies in the surface hydrological schemes causing an unrealistic drying of the soil. In at least one of the models, most likely several of them, an additional factor is an overestimation of incoming solar radiation. Apart from excessive precipitation in mountainous areas in some models they generally show a negative bias due to the drying and decreased advection from the Atlantic. In winter most models have a positive precipitation bias which seems to be caused by an enhancement of advection from the Atlantic and enhanced cyclone activity. Surface air temperature biases are negative probably due to an underestimation of the incoming longwave radiation. Received: 11 December 1996 / Accepted: 17 March 1997     

People as sensors: Mass media and local temperature influence climate change discussion on Twitter

This study examined whether people living in the US connect their sensory experiences with local temperature to climate change and whether mass media influences the process. We used the volume of Twitter messages containing words “climate change” and “global warming” as the indicator of attention that public pays to the issue. Specifically, the goals were: (1) to investigate whether people immediately notice substantial local weather anomalies such as deviations from long-term mean temperatures and connect them to climate change by contributing to climate change discourse on Twitter and (2) to examine the role of mass media in this process. Over 2 million tweets were collected for a two-year period (2012–2013) and were assigned to 157 urban areas in the continental US. The rate of tweeting on climate change was regressed on the time variables, number of climate change publications in the mass media, and a number of temperature variables. The analysis was conducted at the two levels of aggregation – national and local. The high significance of the mass media and temperature variables in the majority of regression models suggests that both the weather and mass media coverage control public interest to the topic. However, no convincing evidence was found that the media acts as a mediator in the relationship between local weather and climate change discourse. Overall, the findings confirmed that the public recognize extreme temperature anomalies and connect these anomalies to climate change.     

Effects of economic recession and local weather on climate change attitudes

How are large companies responding to the challenges of reducing their greenhouse gas (GHG) emissions? An analysis of the published climate change policies and performance of 125 large European companies is presented. The results suggest that most large European companies have now developed the management systems and processes necessary for them to effectively manage their GHG emissions and related business risks. However, there is a significant disconnect between the targets that companies set for themselves and the more ambitious targets being set by the European Union (which has committed to a 20% reduction in its emissions by 2020 against a 1990 baseline). Of the companies surveyed, just over one-third had stabilized or reduced their total GHG emissions over the period 2002–2007, and fewer than one-third expected their emissions to stabilize or reduce in the coming years. The relationship between the quality of corporate policies and performance outcomes (in terms of GHG emissions) suggests that while companies with stronger policies are likely to have relatively better performance, only a minority of those companies with the highest-quality policies are committing to absolute reductions in their GHG emissions.     

Decadal/interdecadal variations of the ocean temperature and its impacts on climate

Decadal/interdecadal climate variability is an important research focus of the CLIVAR Program and has been paid more attention. Over recent years, a lot of studies in relation to interdecadal climate variations have been also completed by Chinese scientists. This paper presents an overview of some advances in the study of decadal/interdecadal variations of the ocean temperature and its climate impacts, which includes interdecadal climate variability in China, the interdecadal modes of sea surface temperature (SST) anomalies in the North Pacific, and in particular, the impacts of interdecadal SST variations on the Asian monsoon rainfall. As summarized in this paper, some results have been achieved by using climate diagnostic studies of historical climatic datasets. Two fundamental interdecadal SST variability modes (7– 10-years mode and 25–35-years mode) have been identified over the North Pacific associated with different anomalous patterns of atmospheric circulation. The southern Indian Ocean dipole (SIOD) shows a major feature of interdecadal variation, with a positive (negative) phase favoring a weakened (enhanced) Asian summer monsoon in the following summer. It is also found that the China monsoon rainfall exhibits interdecadal variations with more wet (dry) monsoon years in the Yangtze River (South China and North China) before 1976, but vice versa after 1976. The weakened relationship between the Indian summer rainfall and ENSO is a feature of interdecadal variations, suggesting an important role of the interdecadal variation of the SIOD in the climate over the south Asia and southeast Asia. In addition, evidence indicates that the climate shift in the 1960s may be related to the anomalies of the North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO). Overall, the present research has improved our understanding of the decadal/interdecadal variations of SST and their impacts on the Asian monsoon rainfall. However, the research also highlights a number of problems for future research, in particular the mechanisms responsible for the monsoon long-term predictability, which is a great challenge in climate research.