This study explored the effect of energy consumption and economic growth on CO2 emissions. The relationship between energy consumption, economic growth and CO2 emissions was assessed using regression analysis (the pooled OLS regression and fixed effects methods), Granger causality and panel cointegration tests. Data from 70 countries between 1994–2013 were analysed. The result of the Granger causality tests revealed that the study variables (population, capital stock and economic growth) have a bi-directional causal relationship with CO2 emissions, while energy consumption has a uni-directional relationship. Likewise, the outcome of the cointegration tests established that a long-run relationship exists among the study variables (energy consumption and economic growth) with CO2 emissions. However, the pooled OLS and fixed methods both showed that energy consumption and economic growth have a significant positive impact on CO2 emissions. Hence, this study supports the need for a global transition to a low carbon economy primarily through climate finance, which refers to local, national, or transnational financing, that may be drawn from public, private and alternative sources of financing. This will help foster large-scale investments in clean energy, that are required to significantly reduce CO2 emissions.

PurposeWhile circular economy (CE) is fast becoming a political and economic agenda for global urban development, there are still substantial knowledge gaps in possible strategies to speed up such transition, especially in the construction industry. This study analyses literature surrounding CE to unpack current trends possible future research directions to foster CE implementation in the construction industry.Design/methodology/approachThe study undertakes a systematic review of CE literature published between 1990 and 2019. It adopts a five-stage procedure as a methodological approach for the review: formulation of the research question(s), locating and identifying relevant studies, selection and evaluation of studies, analysis or synthesis and results reporting.FindingsThe findings on CE research in the construction industry show extensive focus on resource use and waste management. There are limited investigations in other areas of construction such as supply chain integration, building designs, policy, energy efficiency, land use, offsite manufacturing, whole life costing, and risk, cost reduction, cost management, health and safety management. The study findings provide evidence that current CE practice fails to incorporate other areas that would facilitate the network of true circular construction industry.Originality/valueThis research provides a comprehensive overview of research efforts on CE in the construction context, identifying areas of extensive and limited coverage over three decades. Besides, it identifies possible pathways for future research directions on CE implementation, towards the accelerated transition to a true circular construction industry for the benefit of funding bodies and researchers.

Purpose The purpose of this paper is to present a capability maturity model (CMM) developed to implement continuous improvement in small and medium scale construction companies (SMSCC) in Nigeria. Design/methodology/approach A multi-strategy approach involving qualitative studies of SMSCC in Nigeria was conducted. Semi-structured interviews were conducted with purposively selected construction experts in Nigeria to identify variables essential for continuous improvement in SMSCC. Data collected were thematically analysed using NVIVO. Subsequently, a system thinking approach is employed to design and develop the CMM for implementing continuous improvement SMSCC, by exploring possible relationships between the variables established. Findings CMM provided a five-level approach for the inclusion of investigated variables such as team performance; culture; structure; post-project reviews, financial risk management, waste management policy and cost control. These variables are factors leading to continuous improvement in SMSCC, implementable within a six to seven and a half years’ timeline. Practical implications The system thinking model revealed cogent archetypes in the form of reinforcing loops that can be applied in developing the performance of SMSCC. Continuous improvement is feasible. However, it takes time to implement. Further longitudinal studies on the cost of implementing continuous improvement through CMM a knowledge transfer project can be initiated. Originality/value A methodical strategy for enhancing the effectiveness and operations of SMSCC in developing countries can be extracted from the causal loop diagram and the CMM.

The devastating impacts that bio-degradable products such as plastic bags are having on human health, wildlife, and the environment is enormous, especially single-use once. Single-use plastics are non-biodegradable products and does not undergo biological decomposition nor degenerate. This review examines various government regulations targeted at changing behaviour against plastic bags consumption and their effectiveness. Following a rigorous search in 13 databases, including PubMed, Science Direct, Springer Nature, etc. only 17 peer-reviewed journal articles that are published between 2000 and 2019 and met the inclusion criteria were included in the study. Each study’s methodological quality was assessed using the GRADE system, and data were extracted using a uniquely designed form. The results revealed that regulations based solely on the thickness of plastic bags does not reduce plastic bags consumption. However, regulations focused on banning ‘single-use’ plastic bag usage, imposing higher taxes and levies on consumers, significantly reduce plastic bags consumption. Overall, the latter is considered the most effective. Also, the results show that attitude, perception and behaviour change toward bio-degradable products or climate-friendly behaviour can be significantly influenced by public policy or regulations. Although the behaviour seems short-lived in some countries, therefore further studies need to probe on why. Also, the absence of a national regulatory strategy in North America reduced the inclusion of studies from the region, hence need for more research focusing on sub-national regulations.

Transitioning from demolition to deconstruction practices for end-of-life performances is gaining increasing attention following the need for the construction industry to minimise construction and demolition waste. Building information modelling (BIM) presents an opportunity for sustainable deconstruction. However, the notion of BIM for deconstruction (BIMfD) is still in its infancy in the United Kingdom. Although a few studies on BIMfD are evident, a focus on identifying the underlying factors necessary for successful implementation of BIMfD is lacking. The purpose of this study was to identify and analyse the underlying factors necessary for BIMfD implementation in the UK construction industry. It employed a four-stage research design. The reviewed literature explored extant views on BIM implementation factors to identify an initial list of possible factors influencing BIMfD implementation. Subsequently, a mix of questionnaire, focus group discussions and structured interviews were employed at various stages to refine and contextualise 15 factors necessary for BIMfD implementation in the UK construction industry. The contextual interrelationships among the factors were evaluated using interpretive structured modelling (ISM). This evaluation culminated in a BIMfD implementation factor model. The findings identified BIMfD experts, responsiveness of business models to innovative practices and industry’s acceptance to embrace change as the principal factors influencing BIMfD implementation in the UK. The implications of the findings attest that BIMfD experts and advisors must champion the adoption and implementation of BIMfD in the UK and business models need to become more responsive to accommodate BIMfD innovative practices. A BIMfD framework was conceptualised. Even though the BIMfD framework was designed from the UK perspective, the global construction industry can leverage the outcomes of this study. This paper, therefore, brings to the fore, a hierarchical BIMfD implementation factor model to support improved deconstruction practices in the construction industry.