Abstract Social scientists have argued that good communication around risks in climate hazards requires information to be presented in a user-relevant way, allowing people to better understand the ...factors controlling those risks. We present a potentially useful way of doing this by explaining future UK winter precipitation in terms of changes in the frequency, and associated average rainfall, of local pressure patterns that people are familiar with through their use in daily weather forecasts. We apply this approach to a perturbed parameter ensemble (PPE) of coupled HadGEM3-GC3.05 simulations of the RCP8.5 emissions scenario, which formed part of the UK Climate Projections in 2018. The enhanced winter precipitation by 2050–99 is largely due to an increased tendency towards westerly and south-westerly conditions at the expense of northerly/easterly conditions. Daily precipitation is generally more intense, most notably for the south-westerlies. In turn, we show that the changes in the frequency of the pressure patterns are consistent with changes in larger scale drivers of winter circulation and our understanding of how they relate to each other; this should build user confidence in the projections. Across the PPE, these changes in pressure patterns are largely driven by changes in the strength of the stratospheric polar vortex; for most members the vortex strengthens over the twenty-first century, some beyond the CMIP6 range. The PPE only explores a fraction of the CMIP6 range of tropical amplification, another key driver. These two factors explain why the PPE is skewed towards exploring the more westerly side of the CMIP6 range, so that the PPE’s description of UK winter precipitation changes does not provide a full picture.
Concurrent extreme events, i.e. multi-variate extremes, can be associated with strong impacts. Hence, an understanding of how such events are changing in a warming climate is helpful to avoid some ...associated climate change impacts and better prepare for them. In this article, we analyse the projected occurrence of hot, dry, and wet extreme events' clusters in the multi-model ensemble of the 6th phase of the Coupled Model Intercomparison Project (CMIP6). Changes in 'extreme extremes', i.e. events with only 1% probability of occurrence in the current climate are analysed, first as univariate extremes, and then when co-occurring with other types of extremes (i.e. events clusters) within the same week, month or year. The projections are analysed for present-day climate (+1 °C) and different levels of additional global warming (+1.5 °C, +2 °C, +3 °C). The results reveal substantial risk of occurrence of extreme events' clusters of different types across the globe at higher global warming levels. Hotspot regions for hot and dry clusters are mainly found in Brazil, i.e. in the Northeast and the Amazon rain forest, the Mediterranean region, and Southern Africa. Hotspot regions for wet and hot clusters are found in tropical Africa but also in the Sahel region, Indonesia, and in mountainous regions such as the Andes and the Himalaya.
•Separate analysis of climate impact on winter and spring crops.•Summer crop more susceptible to changes in rainfall and temperature.•Silty-clay soil showed higher buffering capacity than the sandy ...soil.
In this study, we explored how changing climate conditions in the 20th and 21st century affect summer and winter crop yields the southeast United States. An ensemble of 10 global circulation models (GCMs) were utilized and the uncertainties associated to their estimates were calculated. The objectives of this study were to utilize historical and projected climate data to (i) analyse historical and projected precipitation and temperature separately for a winter and a summer crop; (ii) evaluate how these climate factors impact the crop yield and the water use; (iii) quantify for the two crops, and for vegetative vs. reproductive stages, the impacts of climate extremes on crop yield and water use. The daily weather data for both historical and projected periods were obtained from the Multivariate Adaptive Constructed Analogs (MACA) downscaled Coupled Model Intercomparison Project Phase 5 (CMIP5) datasets. A series of 16 climate extremes indices mostly selected from the Expert Team on Climate Change Detection and Indices (ETCCDI) was calculated using the MACA downscaled CMIP5 data. The Decision Support System for Agrotechnology Transfer (DSSAT) model was used to simulate the effects of climate on a summer crop (maize, using the CERES-Maize model) and a winter crop (wheat, using the CERES-Wheat model) crop on a silty-clay and on a sandy soil during the historical baseline (1950–1999) and the projected (2006–2055) periods. Overall, the decadal crop-specific growing season temperature trend showed warming of the southeast with little variability across the climate models for the baseline and an increase uncertainty for future conditions. For each 1°C the simulated maize yield would decrease by 4.6% across the different climate projections, while wheat would be reduced by 3.8%. Water use efficiency decreased under future projections by 2.7% on a silty-clay soil, independently of the winter/summer crop, but on a sandy soil the decrease was 4% for maize and 1.7% for wheat. The impacts of projected temperature and rainfall change will be different for a winter than for a summer crop depending on the type of soil on which the crop is grown.
Heatwaves are defined as unusually high temperature events that occur for at least three consecutive days with major impacts to human health, economy, agriculture and ecosystems. This paper ...investigates: 1) changes in heatwave characteristics such as peak temperature, number of events, frequency and duration over a past 67-year period in Australia; 2) projected changes in heatwave characteristics for this century in Queensland, northeast Australia; and 3) the avoided heatwave impacts of limiting global warming by 1.5 °C, 2.0 °C and 3.0 °C. The results reveal that heatwaves have increased in intensity, frequency and duration across Australia over the past 67 years, such intensification was particularly higher on recent decades. Downscaled future climate projections for Queensland suggest that heatwaves will further intensify over the current century. The projections also highlight that distinct climatic regions within Queensland may have different heatwave responses under global warming, where tropical and equatorial heatwaves appear to be more sensitive to elevated atmospheric CO2 concentrations than temperate and arid regions. The results offer new insights to support climate adaptation and mitigation at regional scales. These findings are already being used by health and emergency services to inform the development of statewide policies to mitigate heatwave impacts.
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•Heatwaves undergone major increases in the 2000's in comparison to previous decades.•Heatwaves have intensified in recent past and are projected to increase faster in future.•Heatwaves may be 85% more frequent if global warming increases from 1.5 to 2.0 °C.•Heatwaves may last up to a month if global warming increases from 1.5 to 3.0 °C.•The findings underpinned health and emergency policies to mitigate heatwaves.
ABSTRACT
As a result of climate change in recent past and unsustainable land management, drought became one of the most impacting disasters and, with the projected global warming, it is expected to ...progressively cause more damages by the end of the 21st century. This study investigates changes in drought occurrence, frequency, and severity in Europe in the next decades. A combined indicator based on the predominance of the drought signal over normal/wet conditions has been used. The indicator, which combines the standardized precipitation index (SPI, which accounts for anomalous low rainfall), the standardized precipitation evapotranspiration index (SPEI, which accounts for high temperatures and scarce precipitations), and the reconnaissance drought indicator (RDI, similar to SPEI but more affected by extreme events), has been computed at 3‐ and 12‐month accumulation scales to characterize trends in seasonal and annual events from 1981 to 2100. Climate data from 11 bias‐adjusted high‐resolution (0.11°) simulations from the EURO‐CORDEX (coordinated regional climate downscaling experiment) have been used in the analyses. For each simulation, the frequency and severity of drought and extreme drought events for 1981–2010, 2041–2070, and 2071–2100 have been analysed. Under the moderate emission scenario (RCP4.5), droughts are projected to become increasingly more frequent and severe in the Mediterranean area, western Europe, and Northern Scandinavia, whereas the whole European continent, with the exception of Iceland, will be affected by more frequent and severe extreme droughts under the most severe emission scenario (RCP8.5), especially after 2070. Seasonally, drought frequency is projected to increase everywhere in Europe for both scenarios in spring and summer, especially over southern Europe, and less intensely in autumn; on the contrary, winter shows a decrease in drought frequency over northern Europe.
We investigate future European drought trends using EURO‐CORDEX bias‐adjusted data. Under the RCP4.5 scenario, droughts are projected to become increasingly more frequent and severe over the Mediterranean, western Europe, and Scandinavia, whereas the European continent – except Iceland – will be affected by more frequent extreme droughts under RCP8.5, especially after 2070. Drought frequency is projected to increase everywhere in Europe in spring and summer (less intensely in autumn), especially over southern Europe, but to decrease in winter over northern Europe. Drought frequency (DRF), extreme drought frequency (ExDRF), and drought severity (DRS) are projected to largely increase over most of Europe in the far future compared to recent decades for both moderate (RCP4.5) and more extreme emission (RCP8.5) scenarios.
Climate change poses certain threats to the World's forests. That is, tree performance declines if species-specific, climatic thresholds are surpassed. Prominent climatic changes negatively affecting ...tree performance are mainly associated with so-called hotter droughts. In combination with biotic pathogens, hotter droughts cause a higher tree vulnerability and thus mortality. As a consequence, global forests are expected to undergo vast changes in the course of climate change. Changed climatic conditions may on the one hand locally result in more frequent dieback of a particular tree species but on the other hand allow other-locally yet absent species-to establish themselves, thereby potentially changing local tree-species diversity. Although several studies provide valuable insights into potential risks of prominent European tree species, we yet lack a comprehensive assessment on how and to which extent the composition of European forests may change. To overcome this research gap, we here project future tree-species compositions of European forests. We combine the concept of climate analogs with national forest inventory data to project the tree-species composition for the 26 most important European tree species at any given location in Europe for the period 2061-2090 and the two most relevant CMIP5 scenarios RCP 4.5 and RCP 8.5. Our results indicate significant changes in European forests species compositions. Species richness generally declined in the Mediterranean and Central European lowlands, while Scandinavian and Central European high-elevation forests were projected an increasing diversity. Moreover, 76% (RCP 4.5) and 80% (RCP 8.5) of the investigated locations indicated a decreasing abundance of the locally yet most abundant tree species while 74 and 68% were projected an increasing tree-species diversity. Altogether, our study confirms the expectation of European forests undergoing remarkable changes until the end of the 21st century (i.e., 2061-2090) and provides a scientific basement for climate change adaptation with important implications for forestry and nature conservation.
Climate change can alter the frequency and intensity of extreme rainfall across the globe, leading to changes in hazards posed by rainfall-induced landslides. In recent decades, China suffered great ...human and economic losses due to rainfall-induced landslides. However, how the landslide hazard situation will evolve in the future is still unclear, also because of sparse comprehensive evaluations of potential changes in landslide susceptibility and landslide occurrence frequency under climate change. This study builds upon observed and modelled rainfall data from 24 bias-corrected Coupled Model Intercomparison Project Phase 6 (CMIP6) Global Climate Models (GCMs), a statistical landslide susceptibility model, and empirical rainfall thresholds for landslide initiation, to evaluate changes in landslide susceptibility and landslide occurrence frequency at national-scale. Based on four Shared Socioeconomic Pathways (SSP) scenarios, changes in the rainfall regime are projected and used to evaluate subsequent alterations in landslide susceptibility and in the frequency of rainfall events exceeding empirical rainfall thresholds. In general, the results indicate that the extend of landslide susceptible terrain and the frequency of landslide-triggering rainfall will increase under climate change. Nevertheless, a closer inspection provides a spatially heterogeneous picture on how these landslide occurrence indicators may evolve across China. Until the late 21st century (2080–2099) and depending on the SSP scenarios, the mean annual precipitation is projected to increase by 13.4 % to 28.6 %, inducing an 1.3 % to 2.7 % increase in the modelled areal extent of moderately to very highly susceptible terrain. Different SSP scenarios were associated with an increase in the frequency of landslide-triggering rainfall events by 10.3 % to 19.8 % with respect to historical baseline. Spatially, the southeastern Tibetan Plateau and the Tianshan Mountains in Northwestern Basins are projected to experience the largest increase in landslide susceptibility and frequency of landslide-triggering rainfall, especially under the high emission scenarios. Adaptation and mitigation methods should be prioritized for these future landslide hotspots. This work provides a better understanding of potential impacts of climate change on landslide hazard across China and represents a first step towards national-scale quantitative landslide exposure and risk assessment under climate change.
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•Changes in landslide susceptibility and the frequency of critical rainfall events under SSP scenarios were assessed.•Multiple latest CMIP6 model ensembles were used for reliable projections.•Projected precipitation is expected to induce an increase in landslide susceptibility and frequency under SSPs.•The presented method is applicable to evaluate climate change impacts on landslide occurrence.
Among the tropical oceans, the western Indian Ocean hosts one of the largest concentrations of marine phytoplankton blooms in summer. Interestingly, this is also the region with the largest warming ...trend in sea surface temperatures in the tropics during the past century—although the contribution of such a large warming to productivity changes has remained ambiguous. Earlier studies had described the western Indian Ocean as a region with the largest increase in phytoplankton during the recent decades. On the contrary, the current study points out an alarming decrease of up to 20% in phytoplankton in this region over the past six decades. We find that these trends in chlorophyll are driven by enhanced ocean stratification due to rapid warming in the Indian Ocean, which suppresses nutrient mixing from subsurface layers. Future climate projections suggest that the Indian Ocean will continue to warm, driving this productive region into an ecological desert.
Key Points
Reduction of up to 20% in marine phytoplankton in the Indian Ocean during the past six decades
Reduction in marine productivity is attributed to the rapid warming in the Indian Ocean
Future climate projections indicate further warming and subsequent reduction in marine productivity
We present the global general circulation model IPSL-CM5 developed to study the long-term response of the climate system to natural and anthropogenic forcings as part of the 5th Phase of the Coupled ...Model Intercomparison Project (CMIP5). This model includes an interactive carbon cycle, a representation of tropospheric and stratospheric chemistry, and a comprehensive representation of aerosols. As it represents the principal dynamical, physical, and bio-geochemical processes relevant to the climate system, it may be referred to as an Earth System Model. However, the IPSL-CM5 model may be used in a multitude of configurations associated with different boundary conditions and with a range of complexities in terms of processes and interactions. This paper presents an overview of the different model components and explains how they were coupled and used to simulate historical climate changes over the past 150 years and different scenarios of future climate change. A single version of the IPSL-CM5 model (IPSL-CM5A-LR) was used to provide climate projections associated with different socio-economic scenarios, including the different Representative Concentration Pathways considered by CMIP5 and several scenarios from the Special Report on Emission Scenarios considered by CMIP3. Results suggest that the magnitude of global warming projections primarily depends on the socio-economic scenario considered, that there is potential for an aggressive mitigation policy to limit global warming to about two degrees, and that the behavior of some components of the climate system such as the Arctic sea ice and the Atlantic Meridional Overturning Circulation may change drastically by the end of the twenty-first century in the case of a no climate policy scenario. Although the magnitude of regional temperature and precipitation changes depends fairly linearly on the magnitude of the projected global warming (and thus on the scenario considered), the geographical pattern of these changes is strikingly similar for the different scenarios. The representation of atmospheric physical processes in the model is shown to strongly influence the simulated climate variability and both the magnitude and pattern of the projected climate changes.
The expansion of marine renewable power is a major alternative for the reduction of greenhouse gases emissions. In Europe, however, the high penetration of offshore wind brings intermittency and ...power variability into the existing power grid. Offshore solar photovoltaic power is another technological alternative under consideration in the plans for decarbonization. However, future variations in wind, air temperature or solar radiation due to climate change will have a great impact on both renewable energy resources. In this context, this study focusses on the offshore energy assessment off the coast of Western Iberia, a European region encompassing Portugal and the Northwestern part of Spain. Making use of a vast source of data from 35 simulations of a research project called CORDEX, this study investigates the complementarity of offshore wind and solar energy sources with the aim of improving the energy supply stability of this region up to 2040. Although the offshore wind energy resource has proven to be higher than solar photovoltaic resource at annual scale, both renewable resources showed significant spatiotemporal energy variability throughout the western Iberian Peninsula. When both renewable resources are combined, the stability of the energy resource increased considerably throughout the year. The proposed wind and solar combination scheme is assessed by a performance classification method called Delphi, considering stability, resource, risk, and economic factors. The total index classification increases when resource stability is improved by considering hybrid offshore wind-photovoltaic solar energy production, especially along the nearshore waters.
•Regional Climate Models reproduce well wind, air temperature and surface radiation.•Offshore wind and solar resources show high temporal variability during the year.•Hybrid wind-solar system reduces spatial and temporal variability of the resource.•Offshore wind resource was rated at least as good in most of the western Iberia.•Hybrid wind-solar system improves the final classification in several areas.
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