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The objective of the study is to verify a hypothesis that a hydrological model, which successfully passed a comprehensive evaluation test (CE-test), is more suitable for climate impact study than that which failed the test. In our study, the CE-test is a specially designed model evaluation procedure, including a set of enhanced tests of model performance and robustness. The hypothesis verification is carried out with two models, ECOMAG and SWAP, which are applied for the Lena and Mackenzie River basins. The following three versions of every model are compared: (1) version A with a priori assigned parameters (without any calibration); (2) version B calibrated against streamflow observations at the basin outlets only, and (3) version C calibrated against streamflow observations at several gauges within the basins. We found that the B and C versions were successful in passing the CE-test, while the A versions failed the test. The C versions performed better than the B versions, especially at the monthly time scale. Then, all model versions were forced by global climate model (GCM) ensemble data to simulate flow projections for the twenty-first century and assess the projection uncertainty. Summarizing the results, we found that the differences in projections (in terms of mean annual changes in discharge and their uncertainties) between A version and two other versions were nearly three times larger than the differences between the B and C versions. Thus, the CE-test results together with the estimated differences in projections give us reason to conclude that the successful comprehensive evaluation of a model increases its confidence and suitability for impact assessment.

We developed the ecosystem vulnerability assessment approach (EVAA) to help inform potential adaptation actions in response to a changing climate. EVAA combines multiple quantitative models and expert elicitation from scientists and land managers. In each of eight assessment areas, a panel of local experts determined potential vulnerability of forest ecosystems to climate change over the next century using EVAA. Vulnerability and uncertainty ratings for forest community types in each assessment area were developed. The vulnerability of individual forest types to climate change varied by region due to regional differences in how climate change is expected to affect system drivers, stressors, and dominant species and the capacity of a forest community to adapt. This assessment process is a straightforward and flexible approach to addressing the key components of vulnerability in a collaborative setting and can easily be applied to a range of forest ecosystems at local to regional scales.

This research aims to study the prolonged effects of underground mining on the ecological environment, particularly on surface soil moisture (SM) and fractional vegetation cover (FVC). Using 21 years of data (2000–2020) from the Xishan mining area, a novel quantitative relational model was developed to disentangle the effects of mining activities from those of climate, soil type, and topography. The findings reveal that climatic factors, such as precipitation and air temperature, have significant effects on SM and FVC, while soil type and topographic features are important factors affecting SM and FVC. After years of data analysis, when controlling for factors such as climate, soil, and topography, there were no significant differences in the effects of different mining areas and types of mining activities on SM and FVC. This suggests that the disturbance of mining activities themselves on local hydrology and ecological environment did not exceed the impact range of climate change, surface characteristic changes, and their own restoration capacity. These research findings offer a comprehensive perspective for understanding the impacts of underground mining activities on ecological landscapes and provide a scientific basis for developing effective strategies for ecological conservation and rehabilitation.

Under a warming climate, changes in hydrological extremes may be more significant than changes in hydrological mean conditions. Due to the high risk of damage and the increasing trends of floods and droughts in Germany, the potential changes in hydrological extreme events are of high importance. However, projections of extreme events particularly for floods are associated with large uncertainties and depend on climate scenarios. If only a few scenarios are applied, there is a danger that the impact assessment is biased. This study aims to evaluate the performance of a set of climate scenarios from the ENSEMBLES project for flood and drought projections and to detect the robust changes using the eco-hydrological model SWIM in five large river basins covering 90 % of the German territory. The study shows that there is a moderate certainty that most German rivers will experience more extreme 50-year floods and more frequent occurrences of 50-year droughts. Projected changes with a high certainty include an increasing trend of floods in the Elbe basin and more frequent extreme droughts in the Rhine basin in 2061–2100. Wetter conditions, i.e., more extreme floods and less frequent droughts, are projected for the alpine rivers in 2021–2060. Using only those RCMs for impact assessments that perform best in the reference period does not guarantee more consistent and certain future projections. Hence, the use of the whole ensemble of available scenarios is necessary to quantify the “full” range of uncertainties corresponding to the current state of knowledge and assuring the robustness of projected change patterns.

One of aviation’s major challenges for the upcoming decades is the reduction in its climate impact. As synthetic kerosene and green hydrogen are two promising candidates, their potentials in decreasing the climate impact is investigated for the mid-range segment. Evolutionary advancements for 2040 are applied, first with an conventional and second with an advanced low-NOx and low-soot combustion chamber. Experts and methods from all relevant disciplines are involved, starting from combustion, turbofan engine, overall aircraft design, fleet level, and climate impact assessment, allowing a sophisticated and holistic evaluation. The main takeaway is that both energy carriers have the potential to strongly reduce the fleet level climate impact by more than 75% compared with the reference. Applying a flight-level constraint of 290 and a cruise Mach number of 0.75, causing 5% higher average Direct Operating Costs (DOC), the reduction is even more than 85%. The main levers to achieve this are the advanced combustion chamber, an efficient contrail avoidance strategy, in this case a pure flight-level constraint, and the use of CO2 neutral energy carrier, in a descending priority order. Although vehicle efficiency gains only lead to rather low impact reduction, they are very important to compensate the increased costs of synthetic fuels or green hydrogen.

Abstract Glacierised river catchments are highly sensitive to climate change, while large populations may depend on their water resources. The irrigation agriculture and the communities along the Tarim River, NW China, strongly depend on the discharge from the glacierised catchments surrounding the Taklamakan Desert. While recent increasing discharge has been beneficial for the agricultural sector, future runoff under climate change is uncertain. We assess three climate change scenarios by forcing two glacio-hydrological models with output of eight general circulation models. The models have different glaciological modelling approaches but were both calibrated to discharge and glacier mass balance observations. Projected changes in climate, glacier cover and river discharge are examined over the twenty-first century and generally point to warmer and wetter conditions. The model ensemble projects median temperature and precipitation increases of + 1.9–5.3 °C and + 9–24%, respectively, until the end of the century compared to the 1971–2000 reference period. Glacier area is projected to shrink by 15–73% (model medians, range over scenarios), depending on the catchment. River discharge is projected to first increase by about 20% in the Aksu River catchments with subsequent decreases of up to 20%. In contrast, discharge in the drier Hotan and Yarkant catchments is projected to increase by 15–60% towards the end of the century. The large uncertainties mainly relate to the climate model ensemble and the limited observations to constrain the glacio-hydrological models. Sustainable water resource management will be key to avert the risks associated with the projected changes and their uncertainties.

Anthropogenic CO2 emissions are causing climate change, and impacts of climate change are already affecting every region on Earth. The purpose of this review is to investigate climate impacts that can be linked quantitatively to cumulative CO2 emissions (CE), with a focus on impacts scaling linearly with CE. The reviewed studies indicate a proportionality between CE and various observable climate impacts such as regional warming, extreme daily temperatures, heavy precipitation events, seasonal changes in temperature and precipitation, global mean precipitation increase over ocean, sea ice decline in September across the Arctic Ocean, surface ocean acidification, global mean sea level rise, different marine heatwave characteristics, changes in habitat viability for non-human primates, as well as labour productivity loss due to extreme heat exposure. From the reviewed literature, we report estimates of these climate impacts resulting from one trillion tonne of CE (1 Tt C). These estimates are highly relevant for climate policy as they provide a way for assessing climate impacts associated with every amount of CO2 emitted by human activities. With the goal of expanding the number of climate impacts that could be linked quantitatively to CE, we propose a framework for estimating additional climate impacts resulting from CE. This framework builds on the transient climate response to cumulative emissions (TCRE), and it is applicable to climate impacts that scale linearly with global warming. We illustrate how the framework can be applied to quantify physical, biological, and societal climate impacts resulting from CE. With this review, we highlight that each tonne of CO2 emissions matters in terms of resulting impacts on natural and human systems.

In this case study, we examine a broad range of impacts on tourism and recreation based on projected changes to Indiana’s climate. The direct impacts of climate change on Indiana include increases in the number of hot and extremely hot days each summer, fewer mild days, more rain, and less snow. Each direct impact will affect tourism and recreation. Additionally, a range of indirect impacts are anticipated, including climate-related changes in health issues, new infrastructure needs, changes in forests and other recreational areas, and shifting consumer attitudes toward travel and recreation. Although direct impacts are predictable, indirect impacts on the complex tourism system are harder to anticipate, and the tourism and recreation industry must build resilience to respond to future change. The paper concludes with recommendations for future study.

Quantitative estimates of the economic damages of climate change usually are based on aggregate relationships linking average temperature change to loss in gross domestic product (GDP). However, there is a clear need for further detail in the regional and sectoral dimensions of impact assessments to design and prioritize adaptation strategies. New developments in regional climate modeling and physical-impact modeling in Europe allow a better exploration of those dimensions. This article quantifies the potential consequences of climate change in Europe in four market impact categories (agriculture, river floods, coastal areas, and tourism) and one nonmarket impact (human health). The methodology integrates a set of coherent, high-resolution climate change projections and physical models into an economic modeling framework. We find that if the climate of the 2080s were to occur today, the annual loss in household welfare in the European Union (EU) resulting from the four market impacts would range between 0.2-1%. If the welfare loss is assumed to be constant over time, climate change may halve the EU's annual welfare growth. Scenarios with warmer temperatures and a higher rise in sea level result in more severe economic damage. However, the results show that there are large variations across European regions. Southern Europe, the British Isles, and Central Europe North appear most sensitive to climate change. Northern Europe, on the other hand, is the only region with net economic benefits, driven mainly by the positive effects on agriculture. Coastal systems, agriculture, and river flooding are the most important of the four market impacts assessed.

Background: Wildfire simultaneity affects the availability and distribution of resources for fire management: multiple small fires require more resources to fight than one large fire does.Aims: The aim of this study was to project the effects of climate change on simultaneous large wildfires in the Western USA, regionalised by administrative divisions used for wildfire management.Methods: We modelled historical wildfire simultaneity as a function of selected fire indexes using generalised linear models trained on observed climate and fire data from 1984 to 2016. We then applied these models to regional climate model simulations of the 21st century from the NA-CORDEX data archive.Key results: The results project increases in the number of simultaneous 1000+ acre (4+ km2) fires in every part of the Western USA at multiple return periods. These increases are more pronounced at higher levels of simultaneity, especially in the Northern Rockies region, which shows dramatic increases in the recurrence of high return levels.Conclusions: In all regions, the models project a longer season of high simultaneity, with a slightly earlier start and notably later end. These changes would negatively impact the effectiveness of fire response.Implications: Because firefighting decisions about resource distribution, pre-positioning, and suppression strategies consider simultaneity as a factor, these results underscore the importance of potential changes in simultaneity for fire management decision-making.