Climatic Change最新文献

Historically, the basic materials industry has had relatively low R&D expenditure levels, raising concerns about meeting 2050 climate targets given the crucial need for innovation and technology advancement in this industry. Decisive government intervention and active support for key technological pathways are required to address significant market failures and catalyse industrial decarbonisation. This Essay lays out the economic justification for an active green industrial policy and proposes key policy design principles, with the aim of striking a balance between facilitating the green industrial transition and maintaining cost efficiency in meeting climate targets.

Since the launch of the Science Based Targets initiative (SBTi), we have witnessed a steady increase in the number of companies committing to climate targets for large-scale reduction of greenhouse gas (GHG) emissions. While recent studies present various methodologies for establishing climate targets (e.g., sectoral decarbonization approach, near-term, long-term, net zero), we still don’t understand the explanatory factors determining the level of ambition companies demonstrate in target setting. In this paper, a two-stage qualitative study is conducted with a sample of 22 companies from five countries. First, these companies’ publicly disclosed climate targets are evaluated according to four target ambition criteria: target type, scope, timeframe, and temperature alignment. Secondly, multiple explanatory factors for target setting were identified during the content analysis of the interviews to see how present these factors appear in the ambition levels. Within companies with highly ambitious climate targets, the findings indicate that certain factors are highly present, including leadership engagement, continual management support, employee involvement, participation in climate initiatives, and stakeholder collaboration. Conversely, none of these key factors are highly present in companies with less ambitious climate targets. Rather, these companies strongly identify the initiating factors of market-related pressures and non-market stakeholder influence as being the driving forces behind their target setting. This paper contributes to the literature on corporate responses to climate change by expanding our understanding of explanatory factors for different corporate climate target ambition levels.

Quantifying the vulnerability of population to multi-faceted climate change impacts on human well-being remains an urgent task. Recently, weather and climate extremes have evolved into bivariate events that heighten climate risks in unexpected ways. To investigate the potential impacts of climate extremes, this study analyzes the frequency, magnitude, and severity of observed and future compound hot-dry extremes (CHDEs) over East Africa. The CHDE events were computed from the observed precipitation and maximum temperature data of the Climatic Research Unit gridded Timeseries version five (CRU TS4.05) and outputs of climate models of Coupled Model Intercomparison Project Phase 6 (CMIP6). In addition, this study quantifies the population exposure to CHDE events based on future population density datasets under two Shared Socioeconomic Pathways (SSPs). Using the 75th/90th and 25th/10th percentile of precipitation and temperature as threshold to define severe and moderate events, the results show that the East African region experienced multiple moderate and severe CHDE events during the last twenty years. Based on a weighted multi-model ensemble, projections indicate that under the SSP5-8.5 scenario, the frequency of moderate CHDE will double, and severe CHDE will be 1.6 times that of baseline (i.e., an increase of 60%). Strong evidence of an upward trajectory is noted after 2080 for both moderate and severe CHDE. Southern parts of Tanzania and northeastern Kenya are likely to be the most affected, with all models agreeing (signal-to-noise ratio, SNR > 1), indicating a likely higher magnitude of change during the mid- and far-future. Consequentially, population exposure to these impacts is projected to increase by up to 60% for moderate and severe CHDEs in parts of southern Tanzania. Attribution analysis highlights that climate change is the primary driver of CHDE exposure under the two emission pathways. The current study underscores the urgent need to reduce CO₂ emissions to prevent exceeding global warming thresholds and to develop regional adaptation measures.

Contextualizing current increases in Northern Hemisphere temperatures is precluded by the short instrumental record of the past ca. 120 years and the dearth of temperature-sensitive proxy records, particularly at lower latitudes south of <50 °N. We develop a network of 29 blue intensity chronologies derived from tree rings of Tsuga canadensis (L.) Carrière and Picea rubens Sarg. trees distributed across the Mid-Atlantic and Northeast USA (MANE)—a region underrepresented by multi-centennial temperature records. We use this network to reconstruct mean March-September air temperatures back to 1461 CE based on a model that explains 62% of the instrumental temperature variance from 1901−1976 CE. Since 1998 CE, MANE summer temperatures are consistently the warmest within the context of the past 561 years exceeding the 1951−1980 mean of +1.3 °C. Cool summers across MANE were frequently volcanically forced, with significant (p<0.05) temperature departures associated with 80% of the largest tropical (n=13) and extratropical (n=15) eruptions since 1461 CE. Yet, we find that more of the identified cool events in the record were likely unforced by volcanism and either related to stochastic variability or atmospheric circulation via significant associations (p<0.05) to regional, coastal sea-surface temperatures, 500-hpa geopotential height, and 300-hpa meridional and zonal wind vectors. Expanding the MANE network to the west and south and combining it with existing temperature-sensitive proxies across North America is an important next step toward producing a gridded temperature reconstruction field for North America.

Recently, the body of research that assesses belief in climate change has grown, as has the number of studies appraising how experience with the impacts of climate change might affect public opinion. However, less research has addressed the question of whether/how people believe climate change will manifest itself in their own lives, or how it might affect behavioral responses more generally. Using two rounds of national survey data from 2016 and 2020, we examine the associations between climate risk, political party affiliation, and one potential planned adaptation behavior, relocation. Our results suggest that both exposure to risk and political identification help shape respondents’ beliefs. Several measures of risk are associated with respondents’ reports that weather/climate might cause them to move in the future and there is evidence to suggest that their awareness of risk may have increased between the two surveys. Regarding political affiliation, we find in one set of analyses that Republicans interviewed in 2020 were less likely than other political subgroups, including Republicans interviewed in 2016, to say weather/climate could have a potentially strong influence on future relocation decisions. We also find strong effects of age in one set of analyses, where younger respondents were much more likely than those at middle or older ages to report that weather/climate could exert a strong to moderate influence on a future move.

Voluntary carbon market schemes facilitate funding for projects promoting sustainable land management practices to sequester carbon in natural sinks such as biomass and soil, while also supporting agricultural production. The effectiveness of VCM schemes relies on accurate measurement mechanisms that can directly attribute carbon accumulation to project activities. However, measuring carbon sequestration in soils has proven to be difficult and costly, especially in fragmented smallholdings predominant in global agriculture. The cost and accuracy limitations of current methods to monitor soil organic carbon (SOC) limit the participation of smallholder farmers in global carbon markets, where they could potentially be compensated for adopting sustainable farming practices that provide ecosystem benefits. This study evaluates nine different approaches for SOC accounting in smallholder agricultural projects. The approaches involve the use of proximal and remote sensing, along with process models. Our evaluation centres on stakeholder requirements for the Measurement, Reporting, and Verification system, using the criteria of accuracy, level of standardisation, costs, adoptability, and the advancement of community benefits. By analysing these criteria, we highlight opportunities and challenges associated with each approach, presenting suggestions to enhance their applicability for smallholder SOC accounting. The contextual foundation of the research is a case study on the Western Kenya Soil Carbon Project. Remote sensing shows promise in reducing costs for direct and modelling-based carbon measurement. While it is already being used in certain carbon market applications, transparency is vital for broader integration. This demands collaborative work and investment in infrastructure like spectral libraries and user-friendly tools. Balancing community benefits against the detached nature of remote techniques is essential. Enhancing information access aids farmers, boosting income through improved soil and crop productivity, even with remote monitoring. Handheld sensors can involve smallholders, given consistent protocols. Engaging the community in monitoring can cut project costs, enhance agricultural capabilities, and generate extra income.

This study uses a new dataset on gauge locations and catchments to assess the impact of 21st-century climate change on the hydrology of 221 high-mountain catchments in Central Asia. A steady-state stochastic soil moisture water balance model was employed to project changes in runoff and evaporation for 2011–2040, 2041–2070, and 2071–2100, compared to the baseline period of 1979–2011. Baseline climate data were sourced from CHELSA V21 climatology, providing daily temperature and precipitation for each subcatchment. Future projections used bias-corrected outputs from four General Circulation Models under four pathways/scenarios (SSP1 RCP 2.6, SSP2 RCP 4.5, SSP3 RCP 7.0, SSP5 RCP 8.5). Global datasets informed soil parameter distribution, and glacier ablation data were integrated to refine discharge modeling and validated against long-term catchment discharge data. The atmospheric models predict an increase in median precipitation between 5.5% to 10.1% and a rise in median temperatures by 1.9 °C to 5.6 °C by the end of the 21st century, depending on the scenario and relative to the baseline. Hydrological model projections for this period indicate increases in actual evaporation between 7.3% to 17.4% and changes in discharge between + 1.1% to –2.7% for the SSP1 RCP 2.6 and SSP5 RCP 8.5 scenarios, respectively. Under the most extreme climate scenario (SSP5-8.5), discharge increases of 3.8% and 5.0% are anticipated during the first and second future periods, followed by a decrease of -2.7% in the third period. Significant glacier wastage is expected in lower-lying runoff zones, with overall discharge reductions in parts of the Tien Shan, including the Naryn catchment. Conversely, high-elevation areas in the Gissar-Alay and Pamir mountains are projected to experience discharge increases, driven by enhanced glacier ablation and delayed peak water, among other things. Shifts in precipitation patterns suggest more extreme but less frequent events, potentially altering the hydroclimate risk landscape in the region. Our findings highlight varied hydrological responses to climate change throughout high-mountain Central Asia. These insights inform strategies for effective and sustainable water management at the national and transboundary levels and help guide local stakeholders.

The present investigation attempted to understand the intensity, frequency and spatial coverage of rainfall, runoff, groundwater and agricultural droughts in the semi-arid region of Maharashtra during 1981–2014. For this, various indices similar to Standardized Precipitation Index (SPI) (probabilistic nature) were applied. The linear regression, partial correlation and Student’s t-Test techniques were also used to evaluate inter-connections in hydro-meteorological and agricultural droughts. The hydrological deficiencies mimic the pattern of meteorological droughts in the study area with respect to coverage and intensity. Moderate hydro-meteorological droughts occurred frequently (once in 3 to 4 years). Additionally, the research highlighted an increase in the frequency and intensity of hydrological droughts during the post-1990 period, possibly linked to anthropogenic interventions (dam constructions and irrigation expansion). Despite El Niño events resulting in below-average rainfall, runoff, and groundwater levels in the study area, other phenomena such as Equatorial Indian Ocean Monsoon Oscillation (EQUINOO) / Indian Ocean Dipole (IOD) may have played a crucial role in major drought occurrences in 1986, 2003, and 2012 (events that happen once in > 30 years). The hydro-meteorological droughts lead to agricultural droughts, as they significantly affect the rainfed and irrigated crops in terms of productivity and cropped area. This effect was particularly notable during severe and region-wide droughts in 1985-86, 2002-03, and 2011-12. Furthermore, the investigation suggested that the study area is likely to experience hydro-meteorological deficiencies with ~ 25% probability between 2029 and 2050, coupled with a significant temperature rise (by 1.05 °C). This projected scenario could exacerbate water scarcity and agricultural distress in the future (up to 2050).

The continuing effects of climate change require farmers and growers to have greater understanding of how these changes affect crop production. However, while climatic data is generally available to help provide much of that understanding, it can often be in a form not easy to digest. The proposed Combined Location Online Weather Data (CLOWD) framework is an easy-to-use online platform for analysing recent and historical weather data of any location within Australia at the click of a map. CLOWD requires no programming skills and operates in any HTML5 web browser on PC and mobile devices. It enables comparison between current and previous growing seasons over a range of environmental parameters, and can create a plain-English PDF report for offline use, using natural language generation (NLG). This paper details the platform, the design decisions taken and outlines how farmers and growers can use CLOWD to better understand current growing conditions. Prototypes of CLOWD are now online for PCs and smartphones.

The special reports of the Intergovernmental Panel on Climate Change (IPCC) have a unique character in IPCC scientific assessment. Their main purpose is to address specific timely issues of policy relevance. This article explores the nature and role of IPCC special reports along the lines of three questions: (1) the history (‘where they come from’); (2) the function (‘what they are doing’); and (3) the future (‘where they are going’). In earlier assessment cycles, special reports were characterised mostly as a direct channel for quickly responding to the request from the United Nations Framework Convention on Climate Change (UNFCCC). The conduct of special reports has been gradually institutionalised to embed its planning in the overall scoping of the entire assessment cycle. More recently, they have become a vehicle to consolidate cross-cutting scientific perspectives and serve the diverse needs of the international policy community, not only the UNFCCC. This historical evolution is, in a sense, the result of striving for greater policy relevance. Special reports have a dual political function—namely, turning into the site or object of politicised debates on science (politicisation) and serving as ‘de facto governance’ with the effect of normalising politically contested ideas (normalisation). This dual function is two different faces emerging from the process into which the IPCC is brought to deal with political controversy. The duality of the two functions also manifests inherent tensions that lie behind the IPCC’s ‘policy-relevant but not policy-prescriptive’ principle. For the future of special reports, the IPCC could reconsider the role of special reports in light of the priority over comprehensive assessment reports, the responsiveness to the UNFCCC request and the selection and scope definition of timely topics. However, there will remain a trade-off between provisional science and lasting political impact caused by the future undertaking of IPCC special reports on any topic.