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In some areas of climate impact analysis, the possible impact of a changing mean climate has been dismissed by some writers either because of a belief that society can adapt to a slowly changing mean and/or because expected rates ...
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In some areas of climate impact analysis, the possible impact of a changing mean climate has been dismissed by some writers either because of a belief that society can adapt to a slowly changing mean and/or because expected rates of future changes lie within or not far outside those experienced in the past. The two standard counter arguments to this optimistic view are: (1) the future will lead to much longer periods of protracted change in one direction, with final conditions well into the no-analogue region; and/or (2) the main impacts will accrue through changes in the frequency of extremes. In the literature on greenhouse effect, lip service is often paid to the effect of changes in the frequency of extremes.
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Climate observations, research, and models are used extensively to help understand key processes underlying changes to the climate on a range of time scales from months to decades, and to investigate and describe possible longer-t...
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Climate observations, research, and models are used extensively to help understand key processes underlying changes to the climate on a range of time scales from months to decades, and to investigate and describe possible longer-term future climates. The knowledge generated serves as a scientific basis for climate services that are provided with the aim of tailoring information for decision-makers and policy-makers. Climate models and climate services are crucial elements for supporting policy and other societal actions to mitigate and adapt to climate change, and for making society better prepared and more resilient to climate-related risks. We present recommendations for future research topics for climate modeling and for climate services. These recommendations were produced by a group of experts in climate modeling and climate services, selected based on their individual leadership roles or participation in international activities. The recommendations were reached through extensive analysis, consideration and discussion of current and desired research capabilities, and wider engagement and refinement of the recommendations was achieved through a targeted workshop of initial recommendations and an open meeting at the European Geosciences Union General Assembly. The findings emphasize how research and innovation activities in the fields of climate modeling and climate services can contribute to improving climate knowledge and information with saliency for users in order to enhance capacity to transition to a sustainable and resilient society. The findings are relevant worldwide but are deliberately intended to influence the European Commission's next major multi-annual framework program of research and innovation over the period 2021-27.
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Understanding adolescent climate change concern (CCC) may be a key strategy for building a citizenry that supports climate change action, as adolescents are likely less influenced by ideological polarization than adults. Prior res...
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Understanding adolescent climate change concern (CCC) may be a key strategy for building a citizenry that supports climate change action, as adolescents are likely less influenced by ideological polarization than adults. Prior research shows that climate education may build concern among adolescents, but other factors such as peer pressure may also be important. We investigated the relationships between CCC, acceptance of anthropogenic global warming (AGW), perceived level of acceptance among friends and family, and frequency of discussion of the issue among 426 middle school students in North Carolina, USA, and developed a novel instrument to measure each of these constructs. Acceptance of AGW had the strongest association with CCC. Frequency of discussion with friends and family was the second strongest predictor. Perceived level of acceptance among family and friends was the third strongest predictor. Model selection results suggest family had more influence than friends in this study. Girls perceived climate change as a higher risk than boys. In addition to building acceptance of AGW, leveraging discussions with peers and especially family may help build concern for climate change among future generations.
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Climate change is often regarded as the poster child of interdisciplinarity. Understanding and defining the problem of climate change, let alone finding effective solutions, needs to draw on extremely diverse disciplines that rang...
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Climate change is often regarded as the poster child of interdisciplinarity. Understanding and defining the problem of climate change, let alone finding effective solutions, needs to draw on extremely diverse disciplines that range from the molecular to the global level and from physical science to ecology, technology, economics, human psychology and political science.
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Two simultaneous extreme events affected tropical South America to the east of the Andes during the austral summer and fall of 2012: a severe drought in Northeast Brazil and intense rainfall and floods in Amazonia, both considered...
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Two simultaneous extreme events affected tropical South America to the east of the Andes during the austral summer and fall of 2012: a severe drought in Northeast Brazil and intense rainfall and floods in Amazonia, both considered records for the last 50 years. Changes in atmospheric circulation and rainfall were consistent with the notion of an active role of colder-than-normal surface waters in the equatorial Pacific, with above-normal upward motion and rainfall in western Amazonia and increased subsidence over Northeast Brazil. Atmospheric circulation and soil moisture anomalies in the region contributed to an intensified transport of Atlantic moisture into the western part of Amazonia then turning southward to the southern Amazonia region, where the Chaco low was intensified. This was favored by the intensification of subtropical high pressure over the region, associated with an anomalously intense and northward-displaced Atlantic high over a relatively colder subtropical South Atlantic Ocean. This pattern observed in 2012 was not found during other wet years in Amazonia such as 1989, 1999, and 2009. This suggests La Nina as the main cause of the abundant rainfall in western Amazonia from October to December, with wet conditions starting earlier and remaining until March 2012, mostly in northwestern Amazonia. The anomalously high river levels during the following May-July were a consequence of this early and abundant rainy season during the previous summer. In Northeast Brazil, dry conditions started to appear in December 2011 in the northern sector and then extended to the entire region by the peak of the rainy season of February-May 2012.Digital Object Identifier http://dx.doi.org/10.1175/JCLI-D-12-00642.1
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Drylands cover about one-half of the land surface in China and are highly sensitive to climate change. Understanding climate change and its impact drivers on dryland is essential for supporting dryland planning and sustainable dev...
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Drylands cover about one-half of the land surface in China and are highly sensitive to climate change. Understanding climate change and its impact drivers on dryland is essential for supporting dryland planning and sustainable development. Using meteorological observations for 1960-2019, the aridity changes in drylands of China were evaluated using aridity index (AI), and the impact of various climatic factors [i.e., precipitation P; sunshine duration (SSD); relative humidity (RH); maximum temperature (Tmax); minimum temperature (Tmin); wind speed (WS)] on the aridity changes was decomposed and quantified. Results of trend analysis based on Sen's slope estimator and Mann-Kendall test indicated that the aridity trends were very weak when averaged over the whole drylands in China during 1960-2019 but exhibited a significant wetting trend in hyperarid and arid regions of drylands. The AI was most sensitive to changes in water factors (i.e., P and RH), followed by SSD, Tmax, and WS, but the sensitivity of AI to Tmin was very small and negligible. Interestingly, the dominant climatic driver to AI change varied in the four dryland subtypes. The significantly increased P dominated the increase in AI in the hyperarid and arid regions. The significantly reduced WS and the significantly increased Tmax contributed more to AI changes than the P in the semiarid and dry subhumid regions of drylands. Previous studies emphasized the impact of precipitation and temperature on the global or regional dry-wet changes; however, the findings of this study suggest that, beyond precipitation and temperature, the impact of wind speed on aridity changes of drylands in China should be given equal attention.
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This study presents a detailed analysis of changes in wind and wave climate in the Western Mediterranean Sea (WMed), based on 41 years of accurate wind and wave hindcasts. The purpose of this research is to assess the magnitude of...
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This study presents a detailed analysis of changes in wind and wave climate in the Western Mediterranean Sea (WMed), based on 41 years of accurate wind and wave hindcasts. The purpose of this research is to assess the magnitude of recent changes in wave climate and to locate the coastal areas most affected by these changes. Starting from the Theil-Sen slope estimator and the Mann Kendall test, trends in mean and Max significant wave heights (SWH) and wind speed (WS) are analysed simultaneously on seasonal and annual scales. Thus, the new wave records observed since 2010 have been located spatially and temporally using a simple spatial analysis method, while the increases in maximum wave heights over the last decade have been estimated and mapped. This work was motivated by evidence pointed out by several authors concerning the influence of global climate change on the local climate in the Mediterranean Sea and by the increase in the number and intensity of wave storm events over recent years. Several exceptional storms have recently been observed along the Mediterranean coasts, including storm Adrian in 2018 and storm Gloria in 2020, which resulted in enormous damage along the French and Spanish coasts. The results of the present study reflect a worrying situation in large part of the WMed coasts. Most of the WMed basin experiences a significant increasing trend in the annual Max of SWH and WS with evident inter-seasonal variability that underlines the importance of multi-scale analysis to assess wind and wave trends. Since 2013, about half of the WMed coastline has experienced records in wave climate, not recorded at least since 1979, and several areas have experienced three successive records. Several WMed coasts are experiencing a worrying evolution of the wave climate, which requires a serious mobilisation to prevent probable catastrophic wave storms and ensure sustainable and economic development.
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The K?ppen climate classification was developed based on the empirical relationship between climate and vegetation. This type of climate classification scheme provides an efficient way to describe climatic conditions defined by mu...
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The K?ppen climate classification was developed based on the empirical relationship between climate and vegetation. This type of climate classification scheme provides an efficient way to describe climatic conditions defined by multiple variables and their seasonalities with a single metric. Compared with a single variable approach, the K?ppen classification can add a new dimension to the description of climate variation. Further, it is generally accepted that the climatic combinations identified with the K?ppen classification are ecologically relevant. The classification has therefore been widely used to map geographic distribution of long term mean climate and associated ecosystem conditions. Over the recent years, there has also been an increasing interest in using the classification to identify changes in climate and potential changes in vegetation over time. These successful applications point to the potential of using the K?ppen classification as a diagnostic tool to monitor changes in the climatic condition over various time scales. This work used a global temperature and precipitation observation dataset to reveal variations and changes of climate over the period 1901-2010, demonstrating the power of the K?ppen classification in describing not only climate change, but also climate variability on various temporal scales. It is concluded that the most significant change over 1901-2010 is a distinct areal increase of the dry climate (B) accompanied by a significant areal decrease of the polar climate (E) since the 1980s. The areas of spatially stable climate regions for interannual and interdecadal variations are also identified, which have practical and theoretical implications.
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Sources of intermodel differences in the global lapse rate (LR) and water vapor (WV) feedbacks are assessed using CO2 forcing simulations from 28 general circulation models. Tropical surface warming leads to significant warming an...
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Sources of intermodel differences in the global lapse rate (LR) and water vapor (WV) feedbacks are assessed using CO2 forcing simulations from 28 general circulation models. Tropical surface warming leads to significant warming and moistening in the tropical and extratropical upper troposphere, signifying a nonlocal, tropical influence on extratropical radiation and feedbacks. Model spread in the locally defined LR and WV feedbacks is pronounced in the Southern Ocean because of large-scale ocean upwelling, which reduces surface warming and decouples the surface from the tropospheric response. The magnitude of local extratropical feedbacks across models and over time is well characterized using the ratio of tropical to extratropical surface warming. It is shown that model differences in locally defined LR and WV feedbacks, particularly over the southern extratropics, drive model variability in the global feedbacks. The cross-model correlation between the global LR and WV feedbacks therefore does not arise from their covariation in the tropics, but rather from the pattern of warming exerting a common control on extratropical feedback responses. Because local feedbacks over the Southern Hemisphere are an important contributor to the global feedback, the partitioning of surface warming between the tropics and the southern extratropics is a key determinant of the spread in the global LR and WV feedbacks. It is also shown that model Antarctic sea ice climatology influences sea ice area changes and southern extratropical surface warming. As a result, model discrepancies in climatological Antarctic sea ice area have a significant impact on the intermodel spread of the global LR and WV feedbacks.
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