Warming Levels Research Articles

Irreversibility of winter precipitation over the Northeastern Pacific and Western North America against CO2 forcing

Comprehending the resilience of regional hydroclimate in response to CO2 removal is essential for guiding future mitigation and adaptation strategies. Using an ensemble of model simulations forced by idealized CO2 ramp-up followed by ramp-down, here we show that the winter precipitation over the Northeastern Pacific and Western North America (NPWNA) is irreversible even if global warming is reversed back to 2 °C level. This asymmetric change features a tripolar pattern and is tied to Aleutian Low intensification, which is driven by both zonal and meridional gradients of sea surface temperature (SST) anomalies in the tropical central-eastern Pacific. Distinct from the zonal SST gradient—explained by different timescales of surface and subsurface warming and ocean dynamical processes, amplified through the Bjerknes feedback—the meridional SST gradient originates from the southward shift of the intertropical convergence zone, maintained by the wind-evaporation-SST feedback. Our findings suggest that the regional hydrological risks over the NPWNA induced by CO2 ramp-up cannot be fully eliminated by CO2 removal even if the global warming level is restored back.

AERA-MIP: emission pathways, remaining budgets, and carbon cycle dynamics compatible with 1.5 and 2 °C global warming stabilization

Abstract. While international climate policies now focus on limiting global warming to well below 2 °C or pursuing a 1.5 °C level of global warming, the climate modelling community has not provided an experimental design in which all Earth system models (ESMs) converge and stabilize at the same prescribed global warming levels. This gap hampers accurate estimations based on comprehensive ESMs of the carbon emission pathways and budgets needed to meet such agreed warming levels and of the associated climate impacts under temperature stabilization. Here, we apply the Adaptive Emission Reduction Approach (AERA) with ESMs to provide such simulations in which all models converge at 1.5 and 2.0 °C warming levels by adjusting their emissions over time. These emission-driven simulations provide a wide range of emission pathways and resulting atmospheric CO2 projections for a given warming level, uncovering uncertainty ranges that were previously missing in the traditional Coupled Model Intercomparison Project (CMIP) scenarios with prescribed greenhouse gas concentration pathways. Meeting the 1.5 °C warming level requires a 40 % (full model range: 7 % to 76 %) reduction in multi-model mean CO2-forcing-equivalent (CO2-fe) emissions from 2025 to 2030, a 98 % (57 % to 127 %) reduction from 2025 to 2050, and a stabilization at 1.0 (−1.7 to 2.9) PgC yr−1 from 2100 onward after the 1.5 °C global warming level is reached. Meeting the 2.0 °C warming level requires a 47 % (8 % to 92 %) reduction in multi-model mean CO2-fe emissions until 2050 and a stabilization at 1.7 (−1.5 to 2.7) PgC yr−1 from 2100 onward. The on-average positive emissions under stabilized global temperatures are the result of a decreasing transient climate response to cumulative CO2-fe emissions over time under stabilized global warming. This evolution is consistent with a slightly negative zero emissions commitment – initially assumed to be zero – and leads to an increase in the post-2025 CO2-fe emission budget by a factor of 2.2 (−0.8 to 6.9) by 2150 for the 1.5 °C warming level and a factor of 1.4 (0.9 to 2.4) for the 2.0 °C warming level compared to its first estimate in 2025. The median CO2-only carbon budget by 2150, relative to 2020, is 800 GtCO2 for the 1.5 °C warming level and 2250 GtCO2 for the 2.0 °C warming level. These median values exceed the median IPCC AR6 estimates by 60 % for the 1.5 °C warming level and 67 % for 2.0 °C. Some of the differences may be explained by the choice of the mitigation scenario for non-CO2 radiative agents. Our simulations highlight shifts in carbon uptake dynamics under stabilized temperature, such as a cessation of the carbon sinks in the North Atlantic and in tropical forests. On the other hand, the Southern Ocean remains a carbon sink centuries after temperatures stabilize. Overall, this new type of warming-level-based emission-driven simulation offers a more coherent assessment across climate models and opens up a wide range of possibilities for studying both the carbon cycle and climate impacts, such as extreme events, under climate stabilization.

The Paths and Enlightenment for Achieving Carbon Neutrality in Chinas Megacities

The climate change problem has gradually become the focus of peoples attention. Climate change will lead to severe environmental issues, such as global warming and sea level rise. As a responsible country, China positively undertakes the responsibility to face current climate issues and comes up with feasible ideas to solve them. Consequently, China announces realizing carbon peak by 2030 and realizing carbon neutrality by 2060. Based on the rapid urbanization process, the emissions of cities are large, particularly in megacities. According to the research, construction, transportation, and energy fields contribute to higher carbon emissions in megacities. This paper employs a method of literature review and case study to analyze the path towards achieving carbon neutrality in China before 2060. Up to now, Chinas megacities have explored different paths to realize carbon emissions reduction in previous fields. Meanwhile, there are some experiences utilized by foreign megacities that are worth learning. In the future, Chinas megacities will find unique paths to realize carbon neutrality, such as regionally coordinated development.

Earth system responses to different levels of greenhouse gas emissions mitigation

Anthropogenic carbon dioxide (CO2) emissions are the main driver of climate change, with global warming increasing almost linearly with cumulative CO2 emissions. Hence, future warming will primarily result from future emissions of CO2 with contributions from other greenhouse gases (mostly CH4 and N2O) and aerosols. Climate projections of the 21st century, such as those assessed by the IPCC, are provided from comprehensive climate models, also called Earth System models, driven by scenarios of the 21st century evolution of emissions from those climate forcers. While it seems now inevitable that the world will reach 1.5°C of warming above pre-industrial levels by the early 2030s, the extent to which we exceed this warming level and how quickly we may be able to reduce temperatures again depends strongly on global activity taken now to limit emissions. In this paper, we review the current understanding on Earth system changes under two highly contrasted possible future worlds. We first focus on high-end scenarios, where anthropogenic emissions continue to increase over the course of the 21st century, leading to large warming levels, associated impacts on all components of the Earth System, and increased risks of triggering tipping points. We then assess low-end scenarios, where anthropogenic emissions rapidly decline, reaching net zero and potentially becoming net negative before the end of the 21st century. Such “overshoot” scenarios lead to a peak in global warming followed by a slow decline in global temperature, with some degree of reversibility in the global carbon cycle and key Earth system components. We also review paleoclimatic information relevant to these two contrasting future worlds. Paleoclimate evidence for geo-biosphere interactions shows that stabilizing feedbacks operate on millennial or longer timescales, whereas destabilizing feedbacks and tipping cascades occurred also on shorter timescales.

Polar ice sheets are decisive contributors to uncertainty in climate tipping projections

The Earth’s climate is a complex system including key components such as the Arctic Summer Sea Ice and the El Niño Southern Oscillation alongside climate tipping elements including polar ice sheets, the Atlantic Meridional Overturning Circulation, and the Amazon rainforest. Crossing thresholds of these elements can lead to a qualitatively different climate state, endangering human societies. The cryosphere elements are vulnerable at current levels of global warming (1.3 °C) while also having long response times and large uncertainties. We assess the impact of interacting Earth system components on tipping risks using an established conceptual network model of these components. Polar ice sheets (Greenland and West Antarctic ice sheets) are most decisive for tipping likelihoods and cascading effects within our model. At a global warming level of 1.5 °C, neglecting the polar ice sheets can alter the expected number of tipped elements by more than a factor of 2. This is concerning as overshooting 1.5 °C of global warming is becoming inevitable, while current state-of-the-art IPCC-type models do not (yet) include dynamic ice sheets. Our results suggest that polar ice sheets are critical to improving understanding of tipping risks and cascading effects. Therefore, improved observations and integrated model development are crucial.

Accelerated Historical and Future Warming in the Middle East and North Africa

AbstractThe present study assesses the climate of the Middle East and North Africa (MENA) in detail, focusing on the historical and future warming trends in the region. The assessment incorporates data from observations, reanalyses, and statistically downscaled climate models from the Coupled Model Intercomparison Project Phases 5 and 6. Since the pre‐industrial era, the observed average climate in the MENA has warmed by 1.5°C and is on the brink of exceeding 2°C. The reanalysis data suggest that the regional warming over some MENA sub‐regions is three times faster than the global average. By the end of the 21st century, the Arabian Peninsula is projected to warm to 2.6°C ± 0.57°C and 7.6°C ± 1.53°C under low and high greenhouse gas emission scenarios, respectively. Distinct warming hotspots emerge over the Arabian Peninsula and Algeria in summer and over Mauritania in West Africa and the Elburz Mountains in Iran in winter. The summer hotspot over the Arabian Peninsula has already warmed by more than 2°C and can potentially warm to approximately 9°C under the high‐emission scenario. As global warming progresses to 1.5, 2.0, 3.0, and 4.0°C, the average temperature over the MENA land is projected to increase by 2.3°C ± 0.18°C, 3.0°C ± 0.22°C, 4.6°C ± 0.26°C, and 6.1°C ± 0.31°C, respectively. The 1.5, 2.0, 3.0, and 4.0°C warming levels over the MENA are expected to predate those of the global mean by two or three decades. Natural climate fluctuations also significantly influence the region's warming, contributing to temperature extremes.

Soil microfauna mediate multifunctionality under multilevel warming in a primary forest

Abstract Soil microfauna play a crucial role in maintaining multiple functions associated with soil phosphorous, nitrogen and carbon cycling. Although both soil microfauna diversity and multifunctionality are strongly affected by climate warming, it remains unclear how their relationships respond to different levels of warming. We conducted a 3‐year multilevel warming experiment with five warming treatments in a subtropical primary forest. Using infrared heating systems, the soil surface temperature in plots was maintained at 0.8, 1.5, 3.0 and 4.2°C above ambient temperature (control). Our findings indicated that low‐level warming (+0.8–1.5°C) increased soil multifunctionality, as well as nematode and protist diversity, compared with the control. In contrast, high‐level warming (+4.2°C) significantly reduced these variables. We also identified significant positive correlations between soil multifunctionality and nematode and protist diversity in the 0–10 cm soil layer. Notably, we found that soil multifunctionality and protist diversity did not change significantly under 3.0°C warming treatment. Our results imply that a temperature increase of around 3°C may represent a critical threshold in subtropical forests, which is of great importance for identifying response measures to global warming from the perspective of microfauna in the surface soil. Our findings provide new evidence on how soil microfauna regulate multifunctionality under varying degrees of warming in primary forests.

Association of Ozone and Temperature with Ischemic Heart Disease Mortality Risk: Mediation and Interaction Analyses.

Global warming and elevated ozone (O3) levels are gradually gaining widespread attention, and exposure to which may cause many physiological changes associated with cardiovascular events such as hypertension, cardiomyocyte apoptosis, etc. In addition, ischemic heart disease (IHD) is the leading cause of death worldwide. However, the contributions of temperature and O3, independently or in combination, to IHD mortality are not well understood. This study employs a two-stage analytical protocol (generalized additive model followed by meta-analysis) to explore the respective associations of temperature and O3 with IHD mortality, and determine their possible mediation and interaction effects. Our results suggest that increases of 10 μg/m3 in O3 and 1 °C in temperature at lag01 day are associated with increased IHD mortality risks of 0.789% and 0.686%, respectively. O3 can mediate the relationship between temperature and IHD mortality, with a pooled estimate of 0.140%, while temperature can mediate the association between O3 and IHD mortality, with a pooled estimate of 0.162%. The additive and multiplicative interaction effects of O3 and temperature were significantly associated with IHD mortality. The study findings demonstrate that higher temperature and O3 concentrations can increase human IHD mortality risk through interaction and mediation effects, providing a scientific basis for the synergistic management of temperature and O3 or associated interventions.

Human Adaption to Climate Change: Marine Disaster Risk Reduction in the Era of Intelligence

With the intensification of global warming and sea level rise, extreme weather and climate events occur frequently, increasing the probability and destructive power of marine disasters. The purpose of this paper is to propose the specific application of artificial intelligence (AI) in marine disaster risk reduction. First, this paper uses computer vision to assess the vulnerability of the target and then uses CNN-LSTM to forecast tropical cyclones. Second, this paper proposes a social media communication mechanism based on deep learning and a psychological crisis intervention mechanism based on AIGC. In addition, the rescue response system based on an intelligent unmanned platform is also the focus of this research. Third, this paper also attempts to discuss disaster loss assessment and reconstruction based on machine learning and smart city concepts. After proposing specific application measures, this paper proposes three policy recommendations. The first one is improving legislation to break the technological trap of AI. The second one is promoting scientific and technological innovation to break through key technologies of AI. The third one is strengthening coordination and cooperation to build a disaster reduction system that integrates man and machine. The purpose of this paper is to reduce the risk of marine disasters by applying AI. Furthermore, we hope to provide scientific references for sustainability and human adaptation to climate change.

Comparative Plastome Analysis Between Endangered Mangrove Species Acanthus ebracteatus and Acanthus Relatives Provides Insights into Its Origin and Adaptive Evolution.

Acanthus ebracteatus is a typical true mangrove species with great ecological and medicinal values. However, it has become endangered in China. Moreover, because of the similar morphology and distribution, it is commonly confused with the congeneric mangrove species, A. ilicifolius,which poseschallenges to the protection and proper medicinal utilization of A. ebracteatus. Plastomes provide a solution for molecular identification and adaptive evolution investigation of plants. In this study, we dissected the complete plastome for A. ebracteatus and performed comparative analysis to A. ilicifolius and three non-mangrove relatives (A. montanus, A. leucostachyus and A. mollis). Both plastome sequences and structure are highly conserved between the two mangrove species, while less similar between mangrove and non-mangrove species. Phylogenetic analysis suggested that the mangrove species were divergent from the non-mangrove groups at approximately 15.15 million years ago (Mya), where early to middle Miocene global warming and high sea level might act as one of the main forces driving the mangrove lineage entering into intertidal environments. Furthermore, 12 single nucleotide polymorphisms (SNPs) and 10 insertions/deletions (indels) were detected between the plastomes of A. ebracteatus and A. ilicifolius. PCR validation further demonstrated the effectiveness of the plastid marker in distinguishing the two sibling mangrove species. Taken together, our study broadens the understanding of the origin and evolution of Acanthus mangrove plants, and provided valuable information on the correct identification and protection of endangered mangrove species A. ebracteatus.

FROT: A Framework to comprehensively describe radiative contributions to temperature responses

Abstract Different human activities and associated emissions of CO2 and non-CO2 radiative forcing agents and feedbacks determine the final state of Earth’s climate. To understand and explain contributions to global temperature changes, many emission-based metrics have been employed, such as CO2-equivalent or -forcing equivalent. None of these metrics, however, include dynamic responses from Earth system feedbacks in terms of carbon and heat redistribution, known to play an increasingly important role in ambitious mitigation scenarios. Here we introduce a framework that allows for an assessment of such feedbacks in addition to CO2, non-CO2 anthropogenic forcing and natural external variability contributions. FROT (Framework for Radiative cOntributions to Temperature response) allows for an assessment of components of direct radiative impact to the system (climate forcing), as well as Earth system feedbacks concerning heat and carbon. The framework is versatile in terms of applications and allows for exploring individual components contributions to, for example, temperature stabilisation simulations, or comparisons in different models and scenarios, as it can reasonably explain their simulated temperature variability. Here, we apply FROT to both an intermediate complexity and a fully coupled Earth system model, as we simulate highly ambitious mitigation scenarios. Comparing temperature stabilisation scenarios, we can show that both net-zero CO2 emissions and small amounts of positive CO2 emissions could lead to a stable global temperature trajectory. Our assessment reveals that the effects of non-CO2 climate forcings, especially the development of sulphate aerosols in the atmosphere, and the dynamics of the carbon cycle, play a pivotal role in the final level of warming and in enabling a temperature stabilisation. Under highly ambitious climate mitigation scenarios it becomes crucial to include Earth system feedbacks, specifically ocean heat uptake, to understand interannual to decadal temperature development, since previously secondary processes now become increasingly dominant. Our framework offers the opportunity to do so.

Exploring climate stabilisation at different global warming levels in ACCESS-ESM-1.5

Abstract. Under the Paris Agreement, signatory nations aim to keep global warming well below 2 °C above pre-industrial levels and preferably below 1.5 °C. This implicitly requires achieving net-zero or net-negative greenhouse gas emissions to ensure long-term global temperature stabilisation or reduction. Despite this requirement, there have been few analyses of stabilised climates, and there is a lack of model experiments to address our need for understanding the implications of the Paris Agreement. Here, we describe a new set of experiments using the Australian Community Climate and Earth System Simulator Earth system model (ACCESS-ESM-1.5) that enables the analysis of climate evolution under net-zero emissions, and we present initial results. Seven 1000-year-long simulations were run with global temperatures stabilising at levels in line with the Paris Agreement and at a range of higher global warming levels (GWLs). We provide an overview of the experimental design and use these simulations to demonstrate the consequences of delayed attainment of global net-zero carbon dioxide emissions. We show that there are substantial differences between transient and stabilising climate states and differences in stabilisation between GWLs. As the climate stabilises under net-zero emissions, we identify significant and robust changes in temperature and precipitation patterns including continued Southern Ocean warming and changes in regional precipitation trends. Changes under net-zero emissions differ greatly between regions, including contrasting trajectories of sea ice extent between the Arctic and Antarctic. We also examine the El Niño–Southern Oscillation (ENSO) and find evidence of reduced amplitude and frequency of ENSO events under climate stabilisation relative to projections under transient warming. An analysis at specific GWLs shows that significant regional changes continue for centuries after emission cessation and that these changes are stronger at higher GWLs. Our findings suggest substantial long-term climate changes are possible even under net-zero emission pathways. These simulations are available for use in the community and will hopefully motivate further experiments and analyses based on other Earth system models.

Global warming level indicators of climate change and hotspots of exposure

Abstract In the 21st century, a growing population will be exposed to various hazards caused by a warming climate. Here we present a new database of 12 climate change indicators with a total of 42 variants at different global warming levels (GWLs) (1.2 °C–3.5 °C), which is based on global climate and hydrological model data from the Coupled Model Intercomparison Project round 6 and the Inter-Sectoral Impact Model Intercomparison Project round 3b at 0.5° spatial resolution. It comprises of indicators relating to temperature and precipitation extremes, heatwave events, and hydrological variability. To facilitate the comparison of hazards from different indicators, including for an audience without a scientific background, we have developed a bivariate hazard score which is applied on the grid cell level and incorporates statistics on both the absolute hazard (e.g. low or high precipitation) and the relative change under global warming compared to the reference period (e.g. a large change from low to high precipitation). Additionally, we calculate exposed land area and population through the 21st century for a large set of countries and regions by combining this score with gridded projections of population from the Shared Socioeconomic Pathways (SSPs). The datasets are intended for use by the wider research community and analysts seeking digestible climate hazard and exposure data summarized by GWLs. To illustrate potential uses of the data, in a preliminary analysis we find that even at 1.5 °C large parts of the land area and population face substantial unavoidable risks from multiple indicators, with 86% of the world’s population exposed to at least three indicators with at least medium hazard using the population projections for SSP2 in the year 2050. This picture only worsens with increasing warming, as the land areas facing the highest number of impacts coincide with some of the most densely populated parts of the world.

Thermal Comfort and Restorative Benefits of Waterfront Green Spaces for College Students in Hot and Humid Regions

Global climate change presents a serious threat to the sustainable development of human society, highlighting the urgent need to develop effective adaptation strategies to mitigate the impact of climate-related disasters. Campus waterfront green spaces, integral to the blue-green infrastructure, have been demonstrated to facilitate stress recovery. However, in hot and humid regions, severe outdoor thermal conditions may impair students’ mental and physical health and cognitive function, leading to symptoms such as increased stress, anxiety, and depression. This study examined the influence of outdoor thermal environments on health recovery by selecting three different waterfront green spaces in this climate: Space A (medium water body, sky view factor (SVF) = 0.228), Space B (large water body, SVF = 0.808), and Space C (small water body, SVF = 0.292). The volunteers’ thermal comfort and the restorative benefits of these spaces were evaluated via the perceived restorativeness scale (PRS), heart rate (HR), and electrodermal activity (EDA). We found variations in the neutral physiological equivalent temperature (PET) across the spaces, with values of 28.1 °C (A), 28.9 °C (B), and 29.1 °C (C). The lowest skin conductance recovery rate (RSC) at 0.8811 was observed in Space B, suggesting suboptimal physiological recovery, despite higher scores in psychological recovery (fascination) at 15.23. The level of thermal comfort in this hot and humid region showed a negative correlation with the overall PRS score, the “being away” dimension, and heart rate recovery (RHR). At a lightly warm stress level, where PET increased from 31.0 to 35.7 °C, RSC peaked between 1.45 and 1.53 across all spaces. These insights provide guidance for urban designers and planners in creating waterfront green space designs that can improve the urban microclimate and promote thermal health, achieving sustainable health.

Necromass responses to warming: A faster microbial turnover in favor of soil carbon stabilisation

Microbial byproducts and residues (hereafter ‘necromass’) potentially play the most critical role in soil organic carbon (SOC) sequestration. However, little is known about the influence of climate warming on necromass accumulation in the agroecosystem and the underlying mechanisms associated with microbial life strategies. In order to address these knowledge gaps, we used amino sugars as biomarkers of microbial necromass, and investigated their variation through an 8-year trial in an agroecosystem with two warming levels (+1.6 and + 3.2 °C) compared to ambient temperature. The results showed that the lower warming level had no impact on total microbial necromass carbon. Conversely, warming the soil 3.2 °C above ambient increased total microbial necromass by 17 % and its contribution to SOC by 21.3 %, mainly by increasing fungal necromass (+19.8 %), whereas +3.2 °C warming had no impact on bacterial necromass. At the phylum level, compared with the ambient control, +3.2 °C warming induced an increase in the abundance of Proteobacteria and a decrease in both Acidobacteria and Actinobacteria, whereas in the fungal community, Ascomycota increased and Mortierellomycota decreased. This indicates that r-strategists outcompete K-strategists in warmer climates, which led to increased microbial necromass production and accumulation, as supported by the positive correlation between r-strategists and microbial necromass. Stronger microbial competition for resources also resulted in a higher biomass turnover rate, greater cell death, and greater production of microbial necromass. This was supported by the lower bacterial and fungal network complexity and trophic links under warming conditions. In addition, the necromass generated from accelerated microbial turnover further offsets warming-induced deceases in microbial biomass. Consequently, bulk SOC did not change, despite microbial necromass having a much greater response to warming than the soil C pool. Therefore, future climate warming may influence the composition and persistence of SOC during microbial degradation.

Fire weakens land carbon sinks before 1.5 °C

To avoid the worst impacts of climate change, the Paris Agreement committed countries to pursue efforts to limit global warming to 1.5 °C by urgently reducing greenhouse gas emissions. However, the Paris temperature ambitions and remaining carbon budgets mostly use models that lack feedback among fire, vegetation and carbon, which are essential for understanding the future resilience of ecosystems. Here we use a coupled fire–vegetation model to explore regional impacts and feedbacks across global warming levels. We address whether the 1.5 °C goal is consistent with avoiding significant ecosystem changes when considering shifts in fire regimes. We find that the global warming level at which fire began to impact global carbon storage significantly was 1.07 °C (0.8–1.34 °C) above pre-industrial levels and conclude that fire is already playing a major role in decreasing the effectiveness of land carbon sinks. We estimate that considering fire reduces the remaining carbon budget by 25 Gt CO2 (~5%) for limiting temperature rise to 1.5 °C and 64 GtCO2 (~5%) for 2.0 °C compared to previous estimates. Whereas limiting warming to 1.5 °C is still essential for avoiding the worst impacts of climate change, in many cases, we are already reaching the point of significant change in ecosystems rich in carbon and biodiversity.

Persistently Elevated High‐Latitude Ocean Temperatures and Global Sea Level Following Temporary Temperature Overshoots

AbstractAs exceeding the 1.5°C level of global warming is likely to happen in the near future, understanding the response of the ocean‐climate system to temporarily overshooting this warming level is of critical importance. Here, we apply the Adaptive Emissions Reduction Approach to the Earth System Model GFDL‐ESM2M to conduct novel overshoot scenarios that reach 2.0, 2.5 and 3.0°C of global warming before returning to 1.5°C over the time period of 1861–2500. We also perform a complementary scenario that stabilizes global temperature at 1.5°C, allowing to isolate impacts caused by the temperature overshoots alone, both during their peaks and after their reversals. The simulations indicate that substantial residual ocean surface warming persists in the high latitudes after the overshoots, with most notable regional anomalies occurring in the North Atlantic (up to +3.1°C in the 3°C overshoot scenario compared to the 1.5°C stabilization scenario) and the Southern Ocean (+1.2°C). The residual warming is primarily driven by the recoveries of the Atlantic and Southern Ocean meridional overturning circulation and associated increases in ocean heat transport. Excess subsurface heat storage in low and mid‐latitudes prevents steric sea level rise (SLR) from reverting to 1.5°C stabilization levels in any overshoot scenario, with steric sea level remaining up to 32% higher in the 3°C overshoot scenario on centennial time scales. Both peak impacts and persistent changes after overshoot reversal bear significant implications for future assessments of coastlines, regional climates, marine ecosystems, and ice sheets.

Effects of diluted seawater in drinking water on physiological responses, feeding, drinking patterns, and water balance in crossbred dairy goats

Background and Aim: In tropical regions, the intrusion of saline from seawater (SW) due to global warming and sea level rise in recent years is an important natural factor influencing goat well-being. This study aimed to determine the effects of diluted SW in drinking water on the physiological responses and eating and drinking patterns of crossbred dairy goats under tropical conditions. Materials and Methods: Twenty dairy goats were divided into four groups (five animals each) based on body weight and milk yield. Animals received either fresh drinking water (SW0.0, control) or diluted SW at concentrations of 0.5% (SW0.5, low salinity), 1% (SW1.0, moderate salinity), and 1.5% (SW1.5, high salinity). The experiment was performed for 49 days (1st–7th week). Throughout this period, daily food and water intake were measured every day. In addition, blood collection was performed on day 25. Total urine and feces were collected from days 25 to 29. Meal and drinking patterns were determined on days 31 and 32. Results: Salinity did not influence dry matter intake throughout the experiment (p > 0.05). However, SW had a significant effect on eating patterns. The effect of SW on water intake (WI) was pronounced from the 2nd to 7th weeks of this experiment (p < 0.05). The water balance decreased and plasma antidiuretic hormone levels increased from SW1.5 to SW2.5 compared to the other treatments. Rectal temperature and respiration rate increased from 15:00 to 17:00 in SW1.5 patients. The concentrations of plasma electrolyte, creatinine, and heat shock protein 70 did not differ between treatments (p > 0.05). The urinary excretion of Na+ from SW1.5 and K+ and Cl- from SW1.0 was higher than that from SW0.0 and SW0.5 (p < 0.01). Conclusion: Lactating crossbred goats adapted to low and moderate SW by increasing urine volume and urinary electrolyte excretion (Uex), whereas animals responded to high SW by either increasing Uex or altering drinking patterns to minimize salt stress. Keywords: antidiuretic hormone, dairy goat, kidney, saline water, water balance.

Change in Wind Renewable Energy Potential Under Stratospheric Aerosol Injections

AbstractWind renewable energy (WRE) is an essential component of the global sustainable energy portfolio. Recently, there has been increasing discussion on the potential supplementation of this conventional mitigation portfolio with Solar Radiation Modification (SRM). However, the impact of SRM on conventional mitigation measures has received limited attention to date. In this study, we explore one part of this impact, the potential effect of one type of SRM, Stratospheric Aerosol Injections (SAI), on WRE. Using hourly output from the Earth System Model CNRM‐ESM2‐1, we compare WRE potential under a medium emission scenario (SSP245) and a high emission scenario (SSP585) with an SRM scenario that has SSP585 baseline conditions and uses SAI to offset warming to approximately SSP245 global warming levels. Our results suggest that SAI may affect surface wind resources by modifying large‐scale circulation patterns, such as a significant poleward jet‐shift in the Southern Hemisphere. The modeled total global WRE potential is negligibly reduced under SAI compared to the SSP‐scenarios. However, regional trends are highly variable, with large increases and decreases in WRE potential frequently reaching 12% across the globe with SAI. This study highlights potential downstream effects of SRM on climatic elements, such as wind patterns, and offers perspectives on its implications for our mitigation efforts.

The long-term sea-level commitment from Antarctica

Abstract. The evolution of the Antarctic Ice Sheet is of vital importance given the coastal and societal implications of ice loss, with a potential to raise sea level by up to 58 m if it melts entirely. However, future ice-sheet trajectories remain highly uncertain. One of the main sources of uncertainty is related to nonlinear processes and feedbacks between the ice sheet and the Earth System on different timescales. Due to these feedbacks and ice-sheet inertia, ice loss may already be triggered in the next decades or centuries and will then unfold thereafter on timescales on the order of multiple centuries to millennia. This committed Antarctic sea-level contribution is not reflected in typical sea-level projections based on mass balance changes of the Antarctic Ice Sheet, which often cover decadal-to-centennial timescales. Here, using two ice-sheet models, we systematically assess the long-term multi-millennial sea-level commitment from Antarctica in response to warming projected over the next centuries under low- and high-emission pathways. This allows us to bring together the time horizon of stakeholder planning and the much longer response times of the Antarctic Ice Sheet. Our results show that warming levels representative of the lower-emission pathway, SSP1-2.6, may already result in an Antarctic mass loss of up to 6 m of sea-level equivalent on multi-millennial timescales. This committed mass loss is due to a strong grounding-line retreat in the West Antarctic Amundsen Sea embayment as well as potential drainage from the Ross Ice Shelf catchment and onset of ice loss from Wilkes subglacial basin in East Antarctica. Beyond the warming levels reached by the end of this century under the higher-emission trajectory, SSP5-8.5, a collapse of the West Antarctic Ice Sheet is triggered in the entire ensemble of simulations from both ice-sheet models. Under enhanced warming, next to ice loss from the marine subglacial basins, we also find a substantial decline in ice volume grounded above sea level in East Antarctica. Over the next millennia, this gives rise to a sea-level increase of up to 40 m in our simulations, stressing the importance of including the committed Antarctic sea-level contribution in future projections.