Blockchain Papers

Jiating Wang, Yinan Peng

The increasing need for sustainable practices has encouraged listed companies to participate in carbon trading markets. Traditional centralized systems for managing carbon trading data often face challenges such as limited transparency, poor traceability, and security risks, leading to inefficiencies and compliance issues. This research proposes a blockchain-based framework with smart contracts to provide a secure, decentralized mechanism for recording and verifying carbon trading data. The system ensures tamper-proof logs of emission allowances, trading transactions, and verification events, enabling real-time access for regulatory authorities. Data preprocessing uses Z-score normalization to standardize inputs, while Kernel Principal Component Analysis (KPCA) reduces dimensionality and extracts relevant features. To improve decision-making and cost-efficiency, a Dynamic Cuckoo Search-mutated Locust Swarm Optimization (DCSLSO) algorithm is embedded within the smart contracts to optimize carbon credit allocation and trading strategies. The framework is evaluated through simulations under varying energy demands, carbon prices, and multi-fuel scenarios, using synthetic datasets from energy-intensive industries. The DCSLSO model is implemented using Python and TensorFlow. This research demonstrates that blockchain technology, combined with intelligent smart contracts, can modernize carbon trading for listed companies, fostering transparency, accountability, and long-term economic sustainability in emissions management. This research highlights the potential of combining blockchain technology with intelligent optimization to modernize carbon markets, promoting transparency, accountability, and sustainable economic growth in emissions management.

Kingsley Imandojemu, Aliyu Akorede Rufai, Felix Orole, Romanus Osabohien

ABSTRACT Balancing energy security, energy equity, and environmental sustainability has become increasingly challenging as economies pursue low‐carbon growth amid climate risk and persistent disparities in access to modern energy. Although entrepreneurship is widely recognized as a driver of innovation, its role in addressing the energy trilemma remains contested. This study examines whether, and under what conditions, entrepreneurship contributes to resolving the energy trilemma, using panel data for 64 countries from 2011 to 2022. Drawing on the World Energy Council's trilemma indices, World Bank entrepreneurship and macroeconomic indicators, and OECD‐DAC climate finance data, the analysis employs random‐effects models to capture both within‐ and between‐country variation. The results show that entrepreneurial activity is robustly associated with improved energy security and energy equity, alongside more modest gains in environmental sustainability. Innovation capacity strengthens these relationships, while foreign direct investment and climate finance exhibit uneven effects, tending to support system‐level and environmental outcomes more than inclusive access. Regulatory quality emerges as a critical enabling condition that significantly amplifies the positive impact of entrepreneurship across the energy trilemma. Overall, the findings provide cross‐country evidence that entrepreneurship functions as both an innovation conduit and a decentralizing force in energy transitions, underscoring the importance of predictable regulation and better‐targeted climate finance for access‐oriented clean energy solutions.

Darlington Chizema, Ramos E. Mabugu, Christelle Meniago

This study examines the effect of renewable energy consumption on energy poverty across 43 Sub-Saharan African countries from 2002 to 2021. Using a dynamic panel data approach and a two-step System GMM estimator, it addresses endogeneity concerns in energy poverty analysis. Results show energy poverty is persistent, reflecting deep institutional and infrastructural challenges. While renewable energy consumption is positively associated with energy poverty, the modest impact suggests current investments are concentrated in urban or grid-connected areas, with limited benefits for rural populations. This highlights the need for inclusive, decentralized energy strategies. Human capital emerges as a key factor in alleviating energy poverty, emphasizing the importance of integrating energy access with education and health initiatives. Conversely, GDP per capita, institutional quality, and population density show no significant effects, challenging assumptions that economic growth alone can resolve energy deprivation. The lack of a declining trend in energy poverty underscores the urgency for targeted, long-term interventions. The study advocates pro-poor energy policies, innovative financing, and multi-sectoral approaches linking energy access to broader development goals to advance Sustainable Development Goal 7 (SDG 7). Future research should explore subnational disparities and the varied impacts of renewable technologies to inform context-specific solutions.

Sendy Sendy, Kevin Deniswara

Developments and changes in technology play a significant role in addressing climate change, one of which is decentralized finance, which is currently expanding, and it is still unclear whether it has a dynamic relationship with climate change. This study employs the TVP-VAR Connectedness model with the aim of analyzing the dynamic relationship between the decentralized finance operations and CO2 emissions, the impact of shocks from DeFi operations (Total Value Locked, Volume, Returns, Fees, and Revenues) dynamically increasing CO2 emissions, as well as to assess the role of DeFi returns in strengthening the transmissions of DeFi activity to CO2 emissions. The results show that DeFi operations have a dynamic relationship with CO2 emissions at a moderate level through shocks transmitted by DeFi operational indicators. It was also found that TVL acts more as a net receiver than a net transmitter, unlike Volume, Fees and Revenues. Returns do not significantly transmit shocks to CO2 emissions and are more exogenous in nature, while both TVL and Returns are predominantly influenced by internal idiosyncratic shocks. These findings emphasize the importance of integrating Green FinTech policies to ensure sustainable DeFi growth. The findings also provide important implications for regulators, industry practitioners and academics in their efforts to balance the advancement of DeFi with environmental sustainability.

Yang Hu, Chunlin Lang, Les Oxley, Yang (Greg) Hou

This paper investigates the Granger causality relationship in Bitcoin mining from environmental, sustainable, and miner’s financial perspectives for the period of February 2017 to January 2025. Using a time-varying Granger causality approach of Shi et al. (2018,2020), we explore how the hashrate, a measure of computational power in the Bitcoin mining process, affects energy consumption, electronic waste, and miners’ revenues. Our findings reveal that an increase in hashrate leads to a significant rise in energy use and e-waste and affects miners’ revenues. In addition, we show that mining revenue Granger causes the hashrate, suggesting economic incentives drive the network security through the hashrate. These results offer new insights for investors, policymakers, and environmental economists. • A time-varying Granger causality approach is adopted. • Higher computational power directly increases electricity demand and electronic waste. • The intensity of competition, as measured by hashrate, has a significant impact on mining profitability. • Higher mining revenues incentivise the use of greater hash power.

Hanzun Li, Yige Du, Shaohua Kong

Amid intensifying challenges of global climate change, China—as the world’s largest carbon emitter and a major manufacturing hub—occupies a pivotal position in the global industrial green transformation. Drawing on environmental federalism theory and China’s decentralized governance model, this study develops a framework of “green finance–local government competition–industrial green transformation.” Using panel data from 283 cities in China, we employ spatial econometrics and mediation effect models to test the dual mechanisms by which green finance promotes industrial green transformation. The findings indicate that (1) green finance promotes industrial green transformation; (2) green finance advances industrial green transformation by dismantling China’s traditional local government competition–based development model and removing the institutional suppression arising from “race-to-the-bottom competition”; (3) the effect of green finance exhibits long-run characteristics and a “benchmark–imitation” pattern; (4) baseline environmental conditions strengthen the influence of green finance on industrial green transformation; (5) incorporating ecological civilization development into officials’ performance evaluations can effectively reshape policy incentives and amplify the positive role of green finance. Thus, we propose differentiated green finance policies, the construction of a governance mechanism that integrates fiscal–financial–ecological compensation, and the optimization of ecological civilization assessment indicators to curb campaign-style governance.

Tarek Sadraoui, Sameh Zarai, Mohamed Ali Azouzi

This study examines the interrelation among gold, oil, and cryptocurrency markets and their implications for economic growth in the context of geopolitical turmoil. Employing panel data from 2000 to 2023 of exporter, importer, and mixed economies, we employ Nonlinear Autoregressive Distributed Lag (NARDL) and Panel Vector Autoregression (PVAR) to ascertain asymmetric as well as dynamic relations. Evidence shows that oil and gold price shocks exert significant effects on growth with geopolitical risk increasing volatility, while cryptocurrencies are heterogeneously resilient in panels. The results provide fresh evidence of cross-asset linkages, risk transmission mechanisms, and provide policy implications for policymakers and investors under volatile geopolitical environments.

Abdulkarim K. Alhowaish

Saudi Arabia’s rapid urbanization driven by Vision 2030 demands sustainable municipal finance systems. Using a mixed-methods analysis, this study analyzes 360 expert perspectives and identifies the key challenges of fiscal centralization (β = –0.14), governance deficits (20.2% variance), and overreliance on centralized funding (31.8% variance). However, decentralization (β = 0.31), policy alignment with Vision 2030, and green finance tools emerge as transformative pathways. Regression and correlation analyses reveal that municipal autonomy and legal frameworks are crucial in promoting sustainability integration. This study advocates for fiscal decentralization, Sharia-compliant green bonds, and institutional reforms and offers useful insights for policymakers.

Luqman Hakim Abdul Majid, Yudi Fernando, Ming K. Lim, Ming‐Lang Tseng

Achieving carbon neutrality in supply chains is a complex challenge, given the urgency of climate change mitigation. This paper explores how non-fungible tokens, carbon transparency, and blockchain carbon credits can support reaching carbon neutrality. We surveyed 140 Malaysian semiconductor firms involved in carbon-neutrality initiatives and conducted necessary condition analysis using the bottleneck technique. Our results show that non-fungible tokens enhance carbon transparency by providing traceable, verifiable carbon data. This transparency positively influences the issuance of blockchain carbon credits and carbon neutrality, though its effect is limited. Carbon transparency serves as a mediator between non-fungible tokens and carbon neutrality, underscoring its role in leveraging digital tools for effective carbon management. However, regulatory compliance and scalability challenges hinder both carbon transparency and digital transformation. This paper provides a foundation for integrating non-fungible tokens and blockchain technology into supply chains, offering policymakers pursuing transparent decarbonisation strategies valuable insights.

Xiaoguang Zhou, Xueyao Guo, Jiaxi Ji

No abstract is available for this record.

Hongli Niu, Xiyu Liu

No abstract is available for this record.

Aamir Aijaz Syed, Alka Singh

Advanced blockchain technologies and growing environmental and economic uncertainties have Motivated us to investigate the impact of climate policy uncertainty (CPU) and global economic policy uncertainty (GEPU) on five green cryptocurrencies—ADA, EOS, IOTA, XLM, XTZ—selected based on energy efficiency and mining processes. We examined the short- and long-run impacts of alternative assets on these cryptocurrencies using a nonlinear autoregressive distributed lag model. In the long run, these cryptocurrencies are negatively affected by CPU and GEPU, questioning their safe-haven potential. In the short run, ADA, EOS, and XLM share a positive asymmetric relationship with CPU, whereas all cryptocurrencies have a negative asymmetric relationship with GEPU. Therefore, they can be considered a safe haven. In the short and long term, green bonds exert a positive impact, whereas interest rates, the S&P 500, and the gold index negatively impact these cryptocurrencies. In the short run, Bitcoin shows a negative relationship with EOS, IOTA, and XTZ and a positive relationship with ADA and XLM. Over the long term, Bitcoin exhibits a positive correlation with all cryptocurrencies. USD exhibits a positive relationship in the short run and a negative relationship in the long run with all cryptocurrencies. The findings offer practical implications for portfolio construction and investors dealing in the green cryptocurrency market.

Saba Aslam, Nadia Nazeer, Sania Ahmad

This study adds a new dimension to the body of research by analyzing the impact of fiscal decentralization (FD) on ecological footprints (EF) in Pakistan. In Pakistan, the author examined how financing dependency (FD) affects economic efficiency (EE) from 1990 to 2022, considering time series data with the variables of renewable energy consumption (REC), nonrenewable energy consumption (NREC), GDP and trade openness (TOP). Based on the obtained data, the Auto Regressive Distributed Lag (ARDL) model is chosen. To promote environmental sustainability, the regression analysis reveals that NREC, GDP, and TOP improve EF in Pakistan, while FD and REC reduce EF. This study suggests that Pakistan should optimize the integration of strategies that improve ecological quality by providing the lower level of government with access to environmentally aware technological advancements. These findings could be considered as a policy recommendation.

ZhangSheng Liu, Qingying Zhang, Yuanyuan Gong, Guihua Luo · 5 authors

This study builds on the fiscal decentralization and promotion tournament theories. Utilizing 12 years of panel data from 108 cities in the Yangtze River Economic Belt, we measure the urban carbon productivity index through a super-efficient SBM model that incorporates undesired outputs. We then analyze the effect of local land finance strategy interaction on urban carbon productivity and its mechanism using a spatial self-lagging model. Our key findings reveal: (1) Local governments exhibit mimetic spatial strategy interactions in land finance behavior, both from a geographical distance perspective and when combining economic development levels with geographical distance factors; (2) the interactive behavior of local land finance strategy has a significant inhibitory effect on urban carbon productivity, thereby leading to a loss of urban carbon productivity; (3) the local land finance strategy interaction causes a reduction in urban carbon productivity by changing the cross-city foreign direct investment strategy interaction, environmental regulation strategy interaction, and industrial structure strategy interaction. To achieve these goals, China should foster healthy competition among cities regarding land finance and promote “three-way synergy” between opening up, environmental protection, and industrial upgrading. These coordinated efforts aim to boost urban carbon productivity in the Yangtze Basin while offering developing countries a fresh approach to watershed governance focused on carbon reduction goals.

Abdulkadri Toyin Alabi

• Wavelet coherence reveals Bitcoin’s persistent link with climate policy uncertainty • Green cryptos show context-dependent coherence with climate policy uncertainty • Partial decoupling of green cryptos from Bitcoin emerges at medium-term scales • Twofold framework uncovers time-scale responses of crypto to policy uncertainty • Emphasizes need for stable climate regulations to curb crypto market volatility As global climate policy uncertainty (CPU) intensifies, understanding its intersection with emerging financial technologies becomes increasingly urgent. This study, therefore, investigates the dynamic relationship between CPU and the cryptocurrency market, focusing on Bitcoin and eight leading green cryptocurrencies (Algorand, Cardano, EOS, Hedera, IOTA, Nano, Stellar, and Tezos) using a wavelet coherence analysis. Specifically, the study employs a twofold framework: first, assessing the responsiveness of Bitcoin and green cryptocurrencies to climate policy uncertainty across time scales; second, examining Bitcoin's interaction with green cryptocurrencies to determine their potential stabilizing or decoupling effects amid regulatory uncertainty. The analysis spans from November 2017 to March 2025, capturing multiple phases of regulatory evolution and market transformation. The findings reveal that Bitcoin exhibits a structurally embedded and persistent coherence with CPU, especially over longer investment horizons. This persistent linkage highlights Bitcoin’s role in exacerbating regulatory volatility due to its significant environmental footprint. Conversely, green cryptocurrencies demonstrate more sporadic and context-dependent coherence, often aligning with major climate policy announcements or periods of regulatory scrutiny. While positioned as sustainable alternatives, these assets remain influenced by Bitcoin’s dominance and broader market sentiment, particularly at medium-term investment scales. The partial synchronization observed across key periods suggests an incomplete decoupling from both CPU and Bitcoin. These results highlight the importance of clear and stable climate regulations to reduce market uncertainty and support innovation in sustainable blockchain technologies.

Wulfran Fendzi Mbasso, Ambe Harrison, Idriss Dagal, Mohamed Metwally Mahmoud · 10 authors

This study presents a comprehensive ten-year (2015–2024) evaluation of renewable energy development in Cameroon, emphasizing its intersection with Sustainable Development Goals (SDGs) and broader cross-sectoral development outcomes. Combining time-series analysis of national capacity data, policy content evaluation, and SDG-aligned simulation modeling, the paper assesses both technical and institutional trajectories of the energy transition. Key findings reveal a substantial increase in off-grid installations in underserved regions and a notable rise in grid-connected solar capacity—from 0 MW in 2015 to 63 MW by 2024—driven largely by post-2017 policy decentralization. Hydropower remains the dominant source, but the solar sector exhibited accelerated growth, contributing to enhanced rural electrification and public health infrastructure, with 27 % of rural health institutions now electrified. The renewable energy sector generated an estimated 3500 new jobs over the decade. An SDG alignment index applied across five targets indicates moderate but uneven progress, particularly for Goals 7 (affordable and clean energy), 3 (good health and well-being), and 13 (climate action). Scenario-based simulations underscore that policies promoting decentralized innovation and integrated energy planning significantly enhance rural energy access and socio-economic resilience. However, persistent financing barriers and institutional fragmentation constrain broader impact. The study offers a replicable analytical framework for data-driven, SDG-oriented assessment of energy transitions in Sub-Saharan Africa, contributing actionable insights for sustainable energy policy design in low-resource contexts. • Renewable energy in Cameroon grew steadily between 2015 and 2024. • Off-grid solar access expanded, boosting rural electrification progress. • Policy reforms accelerated decentralized energy access and regulation. • RE growth improved health, jobs, and equity across sectors. • A roadmap aligns RE planning with SDG targets for Cameroon.

Abdulkadri Toyin Alabi, Abdulrasaq Mustapha, Lukman Adebayo-Oke Abdulrauf

Purpose This study aims to evaluate the interplay of climate finance, green technologies, and energy transition in shaping environmental sustainability within the MINT economies (Mexico, Indonesia, Nigeria, Turkey), using the load capacity factor (LCF) as a comprehensive ecological indicator. Design/methodology/approach The study adopts the Cross-Sectionally Augmented Autoregressive Distributed Lag (CS-ARDL) approach, capturing periods from 2000 to 2021. The robustness of the findings is subsequently reinforced through the application of Common Correlated Effects Mean Group and Dynamic Common Correlated Effects Mean Group (DCCEMG) estimators. Findings The results reveal that climate finance significantly enhances the LCF, affirming its role in promoting environmental sustainability through targeted investments in renewables. Energy transition exerts a short-term negative impact on LCF, reflecting the “transitional paradox,” where reliance on energies temporarily exacerbates ecological strain. However, green technologies show no statistically significant effects, likely due to fragmented adoption in MINT economies. Lastly, the study explores the U-shaped trajectory proposed by the LCC (load capacity curve) hypothesis and finds that it is not statistically validated for MINT economies. Practical implications Climate finance should prioritize high-impact renewables over transitional fuels to accelerate long-term sustainability. Moreover, energy transition timelines must account for short-term ecological costs; for instance, MINT nations could pair gas flaring reduction with decentralized solar grids to mitigate transitional harm. Policymakers should consider implementing targeted financial instruments to channel investments into sectors with the highest environmental returns. Originality/value This study introduces pioneering contributions to climate finance and sustainability research by developing a first-of-its-kind climate finance index, which captures the pragmatic energy transition strategies of emerging economies by integrating both renewable and transitional fuel investments.

Kenny Tee, Ghulame Rubbaniy

This study employs a theoretical, system design–based methodology to propose the Palm GreenChain framework—a blockchain-based platform aimed at enhancing traceability, transparency, financial coverage, and accountability in green bond financing for sustainable palm oil production in Malaysia. The methodology integrates Ethereum-compatible smart contracts, ESG oracles, IPFS-based data storage, and DAO (Decentralized Autonomous Organization) governance to structure a digital green bond lifecycle. Rather than relying on empirical data collection, the framework is conceptualized through the development of a multi-layered blockchain architecture and validated via comparative analysis with analogous blockchain applications in agriculture. The proposed system is designed to enable real-time traceability of green bond disbursements, automate ESG compliance verification using satellite and IoT data, and strengthen accountability and access to climate finance for smallholder farmers. By embedding performance-based returns within smart contracts, the model aligns financial incentives with conservation goals. Leveraging Malaysia’s advanced land administration infrastructure and digital capabilities, the framework presents a scalable, open-source solution to reduce greenwashing, expand financial inclusion in underserved agricultural communities, and enhance transparency and investor confidence in sustainable agricultural finance. By directly linking green finance to verifiable sustainability outcomes, Palm GreenChain addresses key limitations in conventional green bond mechanisms. Its applicability across diverse agricultural sectors positions it as a replicable blueprint for broader sustainable development. The framework is openly available via its GitHub repository.

Ki Young Park, Hyuk Jin Ha, Jaemin Ryu

Abstract The role of central banks in advancing sustainable (“green”) digital finance is becoming increasingly significant, positioning them as both facilitators and key actors. This chapter begins by examining how climate-related financial risks may require adjustments to the operational frameworks of central bank policy tools, and highlights recent initiatives undertaken by central banks in response. It then reviews specific cases of sustainable digital finance in the central banking context, including: (1) the BIS’s Project Genesis, which integrates the green bond market and carbon markets through digital technologies; and (2) the collaboration between the Bank of Korea (BOK) and the Korea Exchange (KRX) to explore the application of distributed ledger technology and central bank digital currency (CBDC) in carbon trading.

Jesús Molina‐Muñoz, Andrés Mora‐Valencia, Javier Perote

No abstract is available for this record.

Danqi Chen, Yicheng Wang, Ahmed Muneeb Mehta, Muhammad Asif · 6 authors

Decentralization has become a central theme in debates on economic growth, governance effectiveness, and sustainable development. This study undertakes a bibliometric analysis of 1,322 articles published between 2005 and 2024, retrieved from the Web of Science (WoS) and Scopus databases. Using VOSviewer and Bibliometrix (R-package), the analysis maps research productivity, collaboration networks, and thematic clusters. The results reveal two dominant clusters: fiscal decentralization and its socio-economic and environmental impacts and determinants of decentralization and economic growth . High-ranked journals such as Sustainability and Environmental Science and Pollution Research emerge as leading outlets, while the most productive countries include the China and United States . The findings highlight underexplored areas such as decentralization’s role in renewable energy transitions and green finance. Framed within fiscal federalism and endogenous growth theory, this study contributes by identifying emerging trends, regional gaps, and policy implications for designing decentralization strategies that foster inclusive and sustainable economic growth. However, as a bibliometric study, it is limited in capturing case-specific or contextual details, which could be addressed in future qualitative or mixed-method research.

Burhan Erdoğan

This study analyzes the time-varying interactions among assets in the digital financial asset market. Within the scope of the study, 1,820 daily observations from the 2020–2025 period for Ethereum, Ripple, Binance Coin, Cardano, Stellar, IOTA, Stacks, and Chainlink are examined using the Generalized R² method proposed by Balli et al. (2023). This approach reveals both contemporaneous and lagged interconnectedness between assets, thereby enabling an understanding of how dynamic relationships evolve over time. The results indicate that market interconnectedness is not stable over time and that the transmission of shocks tends to intensify particularly during periods of uncertainty. The findings show that Ethereum maintained a central role throughout the analysis period, while Cardano, STX, LINK, and IOTA were more exposed to shocks. These results underscore the necessity of policy frameworks that address not only individual asset risks but also contagion risks to promote market stability. From an investor’s perspective, it is recommended that portfolio compositions consider both contemporaneous and lagged effects.

Atul Kumar Singh, Nishanth Rao Dugyala, Farzad Pour Rahimian, Faris Elghaish · 5 authors

Existing ESG reporting tools in construction organizations often lack transparency and accountability, presenting significant challenges in effectively managing and reporting ESG data. This research addresses the gap in current reporting practices by proposing and validating a hybrid blockchain solution aimed at enhancing ESG reporting in the Architecture, Engineering, and Construction (AEC) industry. The primary objective is to develop a blockchain-based solution that automates ESG reporting, addressing issues such as data fragmentation, lack of verification, and inefficiencies. Adopting a design science approach, the study develops a conceptual framework that combines Ethereum and Hyperledger Fabric to create a hybrid blockchain model for the prototype. The comprehensive literature review highlights key challenges in ESG practices and emphasizes the potential of blockchain technology to overcome these barriers. The findings show that the hybrid blockchain model successfully automates the ESG reporting process, ensuring transparency, immutability, and accountability. The prototype, validated through a case study involving two construction organizations, demonstrates the feasibility of combining Ethereum and Hyperledger Fabric to manage ESG data, reducing errors, preventing manipulation, and enabling real-time reporting. This research enriches the theoretical understanding of blockchain applications in ESG practices. It provides practical implications by offering a tangible, blockchain-based solution that ensures transparent, reliable, and accountable ESG reporting in the construction industry, ultimately contributing to more sustainable practices.

Loso Judijanto

The current study undertakes a bibliometric examination to analyze the emerging intersection of green finance and environmental monitoring, two critical areas that are driving the global agenda for sustainability. Based on evidence from the Scopus database and visualization using VOSviewer, the study investigates 20 years of scholarly articles to identify major authors, institutions, countries, and thematic groups. The findings of the research pinpoint a discernible chronological development—early research into pollution detection and environmental monitoring systems giving way to subsequent emphasis on financial tools such as green bonds, sustainable development investments, and decentralized finance. Keyword co-occurrence and overlay visualization show how environmentally pertinent data increasingly is being made part of financial decision-making and policy-making. In addition, the study reveals Chinese, American, Indian, and certain European country regional leadership in terming the story. Findings reveal theoretical and empirical contributions through the convergence of environmental science and financial innovation, as well as discovering limitations towards database scope and metrics by citation. Lastly, the study provides a strategic model for scholars, investors, and policymakers seeking to align environmental intelligence with sustainable finance practice.