Greenhouse Gas Concentrations Research Articles

Historical and projected extreme climate changes in the upper Yellow River Basin, China

Considering plateau climate and complex terrain of the upper Yellow River Basin, understanding changes in climate extremes has become increasingly urgent. This study has highlighted the historical changes in climate extremes from 1960 to 2022 based on 20 extreme climate indices, and future changes in climate extremes until 2100 under two Shared Socioeconomic Pathways (SSP126 and SSP585) based on the Coupled Model Intercomparison Project phase 6 (CMIP6) models. We found that historical spatial and temporal evolutions of precipitation extremes (PEs) and temperature extremes (TEs) primarily exhibit increasing trends. The frequency and intensity of PEs primarily show an increasing trend, while the duration of PEs primarily shows a decreasing trend. Both the frequency and duration of cold extremes primarily show a decreasing trend, while the intensity of cold extremes, as well as the intensity, frequency, and duration of warm extremes, primarily show an increasing trend. Future PEs and TEs are expected to continue to intensify even under the most ideal scenario (i.e., SSP126), and these are anticipated to further intensify with increasing radiative forcing levels and greenhouse gas concentrations. Results could provide scientific references for better coping with extreme climate changes in regions of complex terrain and scarce observation station.

The impact of climate change on agriculture and economic growth in Cameroon

<p class="MsoNormal" style="text-align: justify; text-justify: inter-ideograph; line-height: 120%; layout-grid-mode: char; mso-layout-grid-align: none; punctuation-wrap: simple; margin: 12.0pt 0cm 6.0pt 0cm;"><span lang="EN-US" style="font-size: 10.5pt; line-height: 120%; font-family: 'Times New Roman',serif;">T</span><span lang="EN-US" style="font-size: 10.0pt; mso-bidi-font-size: 12.0pt; line-height: 120%; font-family: 'Times New Roman',serif; color: black; mso-themecolor: text1;">he agricultural sector is both one of the key sectors of the Cameroonian economy and the one most influenced by the climate. As indicated in the fifth report of the Intergovernmental Panel on Climate Change, the increase in the concentration of greenhouse gases in the atmosphere, the rise in temperature, changes in rainfall patterns, changes in cloud cover, etc., will continue to change. But how does climate change affect agricultural activities and influence economic growth in Cameroon? The aim of this article is to analyze the impact of climate change on agricultural production and on economic growth in Cameroon over the period 1990–2020. To achieve this objective, a stochastic production function model developed by Just and Pope was used. We also used CO<sub>2</sub> emissions as a proxy for climate change. The results obtained clearly show that the increase in CO<sub>2</sub> emissions has a negative impact on agricultural production and on economic growth.</span></p>

The impact of stratospheric aerosol injection: a regional case study

Stratospheric aerosol injection (SAI) is a form of climate intervention that has been proposed to limit future warming and mitigate some of the adverse impacts of climate change while humanity continues efforts to reduce emissions and atmospheric concentrations of greenhouse gases. In this study, we use an Earth system model to compare the projected effects of a climate change scenario to three different SAI scenarios. Our analysis centers on both climate and crop productivity impacts. We focus on four Global South regions: South Asia, East Asia, South Central America, and West Africa. These regions were selected due to their socioeconomic vulnerability to climate change. The SAI scenarios project reduced temperature extremes and greater wet season precipitation, soil moisture and crop productivity compared to the climate change scenario over all four regions. We also find that the extent to which SAI mitigates crop productivity declines due to climate change is likely greater in South Central America and West Africa than in South and East Asia. Our study is a step toward addressing the need for more regional analyses of the potential impacts of different SAI scenarios.

Onshore Power Supply in Multi-Terminal Maritime Ports

Depending on the type of fuels used by ships in maritime port operations, emissions may contribute more or less to the concentration of greenhouse gases in the atmosphere. The maneuvering of ships at maritime ports uses mainly auxiliary engines, resulting in a significant contribution to emissions. It is understandable that the energy transition in this sector brings benefits and is essential to sustainability, considering its economic and strategic importance. Among the measures established to ensure this transition is the onshore power supply and increased electrification in transportation operations. Maritime ports are not yet prepared for these adjustments, as their heterogeneity and contexts require further research, such as studying the impact of depth on energy consumption, terminal type, and others. The purpose of this paper is to quantify the reduction in greenhouse gas emissions achievable through the implementation of an onshore power supply at the Port of Sines, Portugal. Furthermore, it aims to identify the key factors influencing these adoptions to provide practical recommendations that can guide in advancing energy transition, reducing reliance on fuels, and fostering a sustainable future for the port industry.

Palsa mires of the Northern Hemisphere: environmental characteristics, degradation, and morpho-ecological state

Palsas are unique permafrost landforms that are found in the peatlands of discontinuous and sporadic permafrost regions across the Northern Hemisphere. Palsa mounds create diverse microhabitats for both plant and animal species, making them important features that support the biodiversity of periglacial environments. In addition to their ecological importance, palsa mires also are linked to the global carbon cycle and greenhouse gas emissions through permafrost degradation. Future thawing of permafrost is projected to release large amounts of greenhouse gases from northern peatlands, which can further accelerate global climate warming. Therefore, the changing permafrost dynamics make palsa mires an interesting and critical research topic, one that can help us to better recognize and understand the ongoing and future changes in periglacial environments. The main objective of this thesis is to provide a comprehensive understanding of the environmental factors influencing the occurrence and morpho-ecological state of palsa mires, and to predict future changes in palsa distribution. To achieve this, the thesis employs a multi-scale approach, integrating remote sensing data and statistical modelling across spatial scales ranging from circumpolar to local. First, the environmental characteristics of palsa mires in different parts of the Northern Hemisphere are examined by regional comparisons. Second, circumpolar changes in the suitable environments for palsas are predicted under three different future trajectories of greenhouse gas concentrations. Finally, the morpho-ecological state and degradation of palsa mires at the local scale are investigated in northern Finland. The results show that palsa mires occur in narrow but regionally varying environmental settings, with climatic factors and soil moisture conditions playing a key role in defining suitable environments for the landforms. Without effective climate change mitigation, environments suitable for palsas are projected to almost completely disappear in the northern permafrost region by the end of the century. This projection is consistent with observations showing the overall poor morpho-ecological state of Finnish palsa mires and their significant degradation over the past 50 years. The results also highlight the scale-dependent influence of environmental factors for the occurrence and state of palsa mires. While climatic factors were consistently important across spatial scales, the influence of seasonal freeze-thaw dynamics and soil moisture varied between larger-scale and smaller-scale studies. This thesis highlights the urgent need to understand the impacts of climate change on permafrost landscapes. The predicted dramatic loss of suitable environments for palsa mires underscores their vulnerability and the potential ecological consequences of their degradation. By integrating spatial modelling across different spatial scales, this thesis provides novel insights into the complex interplay between climatic and environmental factors governing the distribution and state of palsas. The results improve our understanding of the ongoing changes in the northern permafrost regions and provide valuable information to support policymakers in planning conservation efforts and in making sustainable decisions regarding permafrost regions and peatlands.

Экономическое обоснование новых технологических решений по лесовосстановлению гарей в центральной лесостепи Российской Федерации

In the presented study, we conducted a feasibility study of the costs of implementing new carbon-saving technological solutions for reforestation of burnt areas, ensuring accelerated and effective restoration of lands damaged by forest fires. An analysis of existing practices of reforestation on burnt areas allowed us to conclude that there are technological solutions that negatively affect the carbon balance, contributing to additional carbon emissions from the soil, when its structure is destroyed. This state of affairs predetermines the need to modernize existing forestry technologies in the direction of reducing emissions and increasing the absorption of greenhouse gases in order to solve the problems of low-carbon development of the country. New technological solutions for reforestation of burnt areas in the central forest-steppe of the Russian Federation were scientifically substantiated, for each phase of the work a scientific justification was given for the machine system, standard costs for the implementation of activities in order to achieve the indicators of the Strategy for the Socioeconomic Development of the Russian Federation with a low level of greenhouse gas emissions. It has been established that the modernization of technological solutions for forest reproduction in the place of burnt areas will be carried out by increasing the number of agricultural techniques and using high-performance and expensive equipment necessary to improve the survival rate of plants and preserve carbon in soils. It has been determined that the project carbon-saving technologies for creating forest crops on burnt areas are distinguished by a higher level of costs compared to the basic technology for creating plantations on forest fund lands. This circumstance will require adjustments to strategic forest planning documents and the attraction of additional funds.

Enhancing soil carbon stocks and soybean yields in coastal areas through the application of biofertilizers

<p>Climate change driven by increased concentration of greenhouse gases in the atmosphere has a significant impact on agricultural systems, particularly in coastal areas that are prone to rising salinity and decreased soil quality. The application of biofertilizers as a strategy for enhancing soil carbon stocks is crucial, given their role in promoting microbial activity and nutrient availability, leading to soil fertility. This study aimed to evaluate the role of biofertilizers in increasing soil carbon stocks and soybean yields in coastal areas. The research was conducted from April to December 2024 in Bengkulu City. The field experiment was designed in a split-plot design, with the main plot was soybean varieties at two levels (i.e., Anjasmoro and Dering I), and the subplot was fertilizer inputs at four levels (i.e., recommended inorganic fertilizer, AMF + Bradyrhizobium + potassium solvent, Bradyrhizobium + phosphate solvent + potassium solvent, and Bioenzyme). The application of biofertilizers and bioenzymes effectively increased soil carbon stock. The potassium-solubilizing microbial population had a greater influence on carbon stocks than the phosphate-solubilizing population and AMF. The use of biofertilizers and bioenzymes also improved soil biological properties and nutrient absorption, thereby contributing to increase soybean yields. This study provides evidence to support government policies promoting biofertilizer use in agriculture, including training and extension programs for farmers, particularly in coastal areas, to improve soil quality, enhance yields, and reduce dependence on chemical fertilizers which are often expensive and can degrade soil quality in the long term.</p>

Extraction of highly crystalline and thermally stable cellulose nanofiber from Heliconia psittacorum L.f. leaves.

Extraction of highly crystalline and thermally stable cellulose nanofiber from Heliconia psittacorum L.f. leaves.

From Hot to Cold Spots: Climate Change is Projected to Modify Diversity Patterns of Small Mammals in a Biodiversity Hotspot

ABSTRACTAimClimate change represents one of the main threats to global biodiversity, and such alterations are expected to induce shifts in distribution ranges and diversity patterns. We evaluate if protected areas and forest remnants in the Atlantic Forest in South America (AF) are projected to ensure the taxonomic diversity (TD) and phylogenetic diversity (PD) of non‐volant small mammals under scenarios of future climate change.LocationAtlantic Forest (AF), South America.MethodsWe used Species Distribution Modelling (SDMs) through an ensemble approach to assess the potential distribution of 101 species of small mammals using present (1979–2013) and future (2050 and 2070) climate scenarios. We consider optimistic and pessimistic greenhouse gas concentration scenarios (SSP370 and SSP585). We accessed TD through the sum of the suitable areas vs. areas of low or unknown suitability distribution maps for each species and PD using the sum of the branch lengths of a phylogenetic tree spatialised.ResultsOur models suggest that climate change is likely to reduce the suitable climatic areas for small mammals in the AF. The shrinkage in the potential distribution is projected to lead to high loss of TD and PD. The southeastern region of the Atlantic Forest is likely to experience the most pronounced decline in PD, while some small areas in the southern Atlantic Forest are projected to increase PD in the future.Main ConclusionsOur models suggest a strong decline in TD and in PD from biodiversity hotspot regions in the AF under climate change scenarios. Since small mammals have low dispersal ability, and because most of the AF is highly fragmented, it is unlikely that this biome will sustain small mammal biodiversity in the future.

Resolving the facility-specific increase of local greenhouse gas concentrations by an industrial wastewater treatment plant

Resolving the facility-specific increase of local greenhouse gas concentrations by an industrial wastewater treatment plant

Fugitive gases reduction and carbon sequestration potential of ecological floating beds.

Fugitive gases reduction and carbon sequestration potential of ecological floating beds.

Differential river-to-sea transfers and CH4 dominance of greenhouse gas emissions in urbanized and impounded estuaries.

Differential river-to-sea transfers and CH4 dominance of greenhouse gas emissions in urbanized and impounded estuaries.

Simulation analysis of the effects of aerosol and surface albedo on the remote sensing detection of greenhouse gases in the short-wave infrared 1.6 μm

Aerosols and surface albedo are major sources of error in retrieving greenhouse gas concentrations using high-resolution shortwave infrared spectroscopy. This study employs a high-precision atmospheric radiative transfer model to simulate the influence of aerosols and six different surface types on satellite-observed spectra in the 1594 nm~1624 nm and 1662 nm~1672 nm bands. The results indicate that as aerosol optical depth (AOD) increases, radiance generally increases, with the most significant change observed over vegetated surfaces, which show a 13.26% variation. Within the CO2 and CH4 absorption bands,the increments of CO2/CH4 under equivalent radiation corresponding to the six surface types are ranked: vegetation, metal material, building material, sedimentary finerock, soil, and sedimentary coarserock. Taking soil surface as an example, the study finds that radiance decreases by approximately 0.41 W/m2/μm/sr for every 1 ppm increase in CO2 concentration and by about 0.86 W/m2/μm/sr for every 1 ppb increase in CH4 concentration. Further analysis shows a near-parabolic relationship between AOD and radiance, with consistent trends for CO2 and CH4. As AOD increases, the concentration of both gases exhibit continuous growth. Vegetated surfaces demonstrate the largest concentration changes, with CO2 and CH4 varying by approximately 40.96 ppm and 137.87 ppb, respectively. Explorations under mixed surface conditions indicate that spectral radiance increases with surface albedo, reaching maximum values of 7.7 W/m2/μm/sr for CO2 and 7.45 W/m2/μm/sr for CH4. These findings underscore the critical roles of aerosols and surface albedo in satellite-based greenhouse gas retrievals, offering valuable theoretical guidance for enhancing the accuracy of remote sensing measurements.

Estimates of emissions from hydrogen transportation fueling infrastructure and vehicles

ABSTRACT Losses of hydrogen used as a transportation fuel could exceed 10% from vehicles and their refueling stations. These emissions erode greenhouse gas benefits because atmospheric hydrogen itself contributes to climate change. Losses at this level are also an economic concern and exacerbate upstream environmental impacts from hydrogen production. We reviewed the literature for estimates of hydrogen emissions within the “pump to wheels” (PTW) boundaries for present day technology. Additional insight was gained from methane emissions from natural gas transportation, a similar but more mature topic. Our effort addressed both fueling stations with on-site production and those employing liquid hydrogen storage with delivery from off-site plants. We considered that liquid hydrogen can be converted to high pressure gaseous hydrogen for vehicle fueling either through use of compressors or cryogenic pumps. Vehicles considered included cars, buses, and trucks employing fuel cells, and trucks employing hydrogen internal combustion engines. Reported losses were scarce and highly variable across studies, due in part to varied technologies and practices and the degree of utilization of the refueling stations. We therefore adopted specific scenarios employing current technology and practices for utilization and refueling of light duty passenger, heavy-duty truck and transit bus fleets to calculate and estimate percentage losses from individual segments of the PTW chain. The largest potential losses were associated with delivery, storage and handling of liquid hydrogen while emissions from compressed hydrogen storage tanks and delivery, vehicle fittings, and refueling nozzle venting were small. Our review will serve to inform subsequent studies of benefits and impacts of hydrogen adoption in the transportation arena. Implication Statement Hydrogen is being presented and adopted as a carbon-free alternative to traditional fossil fuels in the transportation sector. Carbon emissions from hydrogen production have been well characterized, but hydrogen emissions themselves interfere with chemical processes that serve to check concentrations of atmospheric greenhouse gases. Recent published analyses suggest a 100-year global warming potential of approximately 10 for hydrogen, so that direct hydrogen emissions are of concern in quantifying climate change benefits. This is similar to concerns that methane emissions diminish the benefits of natural gas as a low carbon fuel. Our review and study have gathered the scattered literature and data relevant to hydrogen emissions, employed analogies from natural gas deployment, and derived realistic estimates of hydrogen emissions for the pump-to-wheels (PTW) transportation sector. Our results demonstrate that losses depend on the type and scale technology in place and can be substantial as a percentage. The results should be combined with existing upstream climate change emissions for hydrogen production and upstream distribution to improve quantitative assessment of the net environmental benefit offered by hydrogen in the transportation sector. This in turn should guide future investment and policy decisions. A direct implication of the results is that effort should be made to abate pump-to-wheels hydrogen emissions through adoption of best technology and practice, through improvement of hydrogen recovery, and through sizing of fueling infrastructure that is appropriate for vehicle fleet size.

Understanding the Causes and Impact of Pollution: A Comprehensive Analysis and Community Perceptions

The surge in pollution, particularly environmental pollution, can be attributed to several factors. Here are some of the primary contributors: Industrial Activities: The rapid growth of industrialization has resulted in heightened pollution levels. Manufacturing processes release pollutants, such as chemicals, particulate matter, and greenhouse gases, into the air, water, and soil. Vehicular Emissions: The increasing number of vehicles on the roads has led to a rise in the emission of harmful gases like carbon monoxide, nitrogen oxides, and volatile organic compounds. These emissions significantly contribute to air pollution, especially in densely populated urban areas Power Generation: The heavy dependence on fossil fuels for electricity generation plays a substantial role in pollution. The combustion of coal, oil, and natural gas releases pollutants and greenhouse gases into the atmosphere, contributing to air pollution and climate change Deforestation: The clearing of forests for agricultural expansion, urbanization, and other purposes results in the loss of carbon sinks and disrupts ecosystems. Deforestation reduces the Earth's capacity to absorb carbon dioxide, leading to increased concentrations of greenhouse gases and air pollution Agricultural Practices: Certain agricultural practices contribute to pollution as well. The use of chemical fertilizers and pesticides can contaminate water bodies, while the burning of crop residues releases pollutants into the air. These factors collectively contribute to the escalation of pollution levels, highlighting the need for sustainable practices and effective measures to mitigate environmental harm. Waste Disposal: Improper waste disposal, including inadequate management of solid waste and improper treatment of hazardous waste, can lead to pollution of land, water, and air. Landfills and incineration can release harmful substances and greenhouse gases. Pollution, both environmental and atmospheric, has become a critical global issue in recent decades. The deterioration of air quality, water contamination, soil degradation, and the adverse impact on human health and ecosystems have heightened concerns worldwide. Understanding the reasons behind the increase in pollution is essential for addressing this complex problem effectively. By identifying the key factors contributing to pollution, policymakers, scientists, and communities can develop targeted strategies to mitigate its harmful effects. The reasons for the increase in pollution are diverse and multifaceted, often stemming from human activities and societal developments. Industrialization, urbanization, energy production, transportation, and agricultural practices are among the primary contributors to pollution. Understanding and Awareness: Research helps deepen our understanding of the specific factors and activities that contribute to pollution. It sheds light on the complex interactions between human actions and the environment, creating awareness among policymakers, industries, communities, and individuals about the causes and consequences of pollution. Policy and Regulation Development: Findings from research on the reasons for pollution can inform the development of effective policies and regulations. By identifying the major sources and activities responsible for pollution, policymakers can design targeted measures to address them. Research provides the evidence base necessary for implementing regulations that mitigate pollution and protect human health and the environment. Pollution Prevention and Control: Knowledge about the reasons for pollution allows researchers to focus on prevention and control strategies. By understanding the specific causes, researchers can work towards developing innovative technologies, practices, and approaches that minimize or eliminate pollution at its source. This research helps identify best practices for pollution prevention, reduction, and control Ratio studies are statistical analyses of data from appraisals and property valuations. Nearly all states utilise them to produce quantitative measure of the proportion of current market price about which individually estimated taxable property is appraised as well as to offer assessment performance indicators.

Urban Parks and Native Trees: A Profitable Strategy for Carbon Sequestration and Climate Resilience

Urban green spaces are increasingly recognized for their potential to mitigate climate change by reducing atmospheric concentrations of greenhouse gases, especially carbon dioxide (CO2). However, enhancing carbon sequestration efficiency in limited urban green areas remains a significant challenge for sustainable urban planning. Trees are among the most cost-effective and efficient natural carbon sinks, surpassing other types of land cover in terms CO2 absorption and storage. The present study aimed to evaluate the carbon sequestration potential of four native tree species, Pongamia pinnata, Azadirachta indica, Melia azedarach, and Dalbergia sissoo, in urban parks across Multan City, Pakistan. A total of 456 trees of selected species within six parks of Multan City were inventoried to estimate the biomass and carbon stock using species-specific allometric equations. Soil organic carbon at two soil depths beneath the canopy of each tree was also estimated using Walkley–Black method. The findings revealed that the highest mean tree biomass (2.16 Mg ha−1), carbon stock (1.04 Mg ha−1) and carbon sequestration (3.80 Mg ha−1) were estimated for Dalbergia sissoo, while Melia azedarach exhibited the lowest (0.12 Mg ha−1, 0.06 Mg ha−1 & 0.23 Mg ha−1, respectively) across all six parks. The soil carbon stocks ranged from 48.86 Mg ha−1 to 61.68 Mg ha−1 across all study sites. These findings emphasize the importance of species selection in urban green planning for carbon sequestration. Strategic planting of effective native trees like Dalbergia sissoo can mitigate climate change and provide urban forest ecosystem services.

НАУЧНО-МЕТОДИЧЕСКИЕ ОСНОВЫ РЕАЛИЗАЦИИ ПРОЕКТОВ ПО СОКРАЩЕНИЮ ВЫБРОСОВ И УВЕЛИЧЕНИЮ ПОГЛОЩЕНИЯ ПАРНИКОВЫХ ГАЗОВ ЛЕСАМИ В РОССИИ

The article discusses forestry measures aimed at reducing emissions and increasing the absorption of greenhouse gases in the forests of the Russian Federation. The analysis of priority measures has been carried out taking into account the natural and climatic conditions of different regions, which makes it possible to recommend the optimal list of tree species for each of them. The authors analyzed the totality of forestry measures for the priority of their implementation in order to decarbonize. The set of forestry measures includes the selection of forest species that maximize the minimization of emissions and maximize the absorption of greenhouse gases during their breeding in the constituent entities of the Russian Federation. The results of the analysis showed that the most effective in the implementation of decarbonization projects are forest-climatic projects, the article pays special attention to the creation of forest plantations and protective forests, artificial reforestation, as well as operational control of forest fires. It is noted that for the effective implementation of forest-climatic projects, it is necessary to take into account the specifics of regions with a low baseline of natural reforestation. According to these estimates, achieving carbon balance targets is possible in 56 regions of Russia by 2050, which requires the activation of existing government programs and projects in the field of forestry, especially in terms of the development of carbon landfills, including the need to establish the ultimate goal of the carbon landfill project – carbon balance control.

Multi-Scale Temporal Integration for Enhanced Greenhouse Gas Forecasting: Advancing Climate Sustainability

Greenhouse gases (GHGs) significantly shape global climate systems by driving temperature rises, disrupting weather patterns, and intensifying environmental imbalances, with direct consequences for human life, including rising sea levels, extreme weather, and threats to food security. Accurate forecasting of GHG concentrations is crucial for crafting effective climate policies, curbing carbon emissions, and fostering sustainable development. However, current models often struggle to capture multi-scale temporal patterns and demand substantial computational resources, limiting their practicality. This study presents MST-GHF (Multi-Scale Temporal Greenhouse Gas Forecasting), an innovative framework that integrates daily and monthly CO2 data through a multi-encoder architecture to address these challenges. It leverages an Input Attention encoder to manage short-term daily fluctuations, an Autoformer encoder to capture long-term monthly trends, and a Temporal Attention mechanism to ensure stability across scales. Evaluated on a fifty-year NOAA dataset from Mauna Loa, Barrow, American Samoa, and Antarctica, MST-GHF surpasses 14 baseline models, achieving a Test_R2 of 0.9627 and a Test_MAPE of 1.47%, with notable stability in long-term forecasting. By providing precise GHG predictions, MST-GHF empowers policymakers with reliable data for crafting targeted climate policies and conducting scenario simulations enabling proactive adjustments to emission reduction strategies and enhancing sustainability by aligning interventions with long-term environmental goals. Its optimized computational efficiency, reducing resource demands compared to Transformer-based models, further strengthens sustainability in climate modeling, making it deployable in resource-limited settings. Ultimately, MST-GHF serves as a robust tool to mitigate GHG impacts on climate and human life, advancing sustainability across environmental and societal domains.

Frequent land-ocean transboundary migration of tropical heatwaves under climate change

Anthropogenic warming has exacerbated atmospheric heatwaves globally, yet the transboundary migration of heatwaves between land and ocean, along with the anthropogenic influence on this process, remain unclear. Here, we employ a Lagrangian tracking approach to identify and track spatiotemporally contiguous warm-season heatwaves in both reanalyses and simulations. This way, we show that land-ocean transboundary heatwaves, especially in the tropics, exhibit longer persistence, wider areal extent, and greater intensity than those confined to land or ocean. These transboundary migrations are primarily driven by the movement of high-pressure systems (such as the westward extension of subtropical highs) and the propagation of Rossby waves. Associated with increasing greenhouse gas concentrations, the frequency of tropical heatwave migrations has increased over the past four decades, and is projected to accelerate further in the twenty-first century under the high-emissions scenario. Anthropogenically-driven landward migrations are amplified by stronger landward winds that drive heat advection, while oceanward processes are likely intensified by increased land-ocean temperature gradient. These intensified transboundary heatwaves not only accentuate humid heat risks for humans but also threaten ecosystems.

Increased Extreme Precipitation in Western North America from Cut-Off Lows Under a Warming Climate

Cut-off low (COL) pressure systems significantly influence local weather in regions with high COL frequency, particularly in western North America. Nonetheless, future changes in COL frequency, intensity, and precipitation patterns remain uncertain. This study examines projected COL changes and their drivers in western North America under a high greenhouse gas concentration pathway (SSP585) using a multi-model ensemble from CMIP6 and a feature-tracking algorithm. We compare historical simulations (1980–2009) and future projections (2070–2099), revealing a marked increase in COL track density during summer in the northeast Pacific and western United States, while a strong decrease is projected for winter, associated with shifts in jet streams. Climate models project an increase in COL-related precipitation in future climate, with winter and spring experiencing more intense and localized precipitation, while autumn showing a more widespread precipitation pattern. Additionally, there is an increased frequency of extreme precipitation events, though accompanied by large uncertainties. The projected increase in extreme precipitation highlights the need to understand COL dynamics for effective climate adaptation in affected areas. Further research should aim to refine projections and reduce uncertainties, supporting better-informed policy and decision-making.