Green job training encourages workers to build habits to effectively combat climate change even outside work.

Organisational Citizenship Behaviours’ (OCBs) were defined by Organ (1997) as discretionary behaviours, not directly or explicitly recognised by the formal reward system and, taken together, promote the more effective functioning of the organisation. Depending on their nature, OCBs can be categorized in different dimensions (for a review refer to Podsakoff et al., 2000). Williams and Anderson (1991) provided a ‘target-based’ framework in which these voluntary behaviours were divided into OCBs that directly benefit the broader organisation (OCB-O), such as working extra-hours, and OCBs that directly benefit specific organisational members (OCB-I), such as helping a colleague in need. Building on previous literature on OCBs, Boiral (2009) defined OCBEs as, ‘individual and discretionary social behaviors not explicitly recognized by the formal reward system and contributing to improve the effectiveness of environmental management of organizations’ (p. 223). Subsequently, Lamm et al. (2013) stated that OCBEs are, ‘voluntary behaviors not specified in official job descriptions that, through the combined efforts of individual employees, help to make the organization and/or society more sustainable’ (p. 165). Moreover, Robertson and Barling (2017) proposed three categories of OCBEs: i) self-enacted OCBEs, which employees enact without any intentional influence on others; ii) co-worker focused OCBEs, which are directed at influencing and helping co-workers to be more environmentally friendly; and iii) organisationally focused OCBEs, which reflect behaviours aimed at influencing the organisation to improve its environmental performance. Overall, three main features are common to all available definitions: first, OCBEs benefit the environment; OCBEs are discretionary behaviours not recognised and rewarded by the formal organisational system; and third, cumulatively, they increase the effectiveness of the organisation in becoming ‘green’. Therefore, leveraging i) the ‘target-based’ framework by Williams and Anderson (1991) and ii) the OCBEs categories proposed by Robertson and Barling (2017), this study focused on two main types of OCBEs: Organisation-focused OCBE (OCBE-O) that includes employees' discretionary, environmentally related behaviours not recognised by the formal reward system that support the environmental management of the organisation. The OCBE-O documents employees' voluntary participation in environmentally related projects, courses, and related events implemented by the organisation; Co-worker focused OCBE (OCBE-I) that includes employees' discretionary environmentally related behaviours not recognised by the formal reward system that support and help colleagues in integrating environmental protection into the organisation. OCBE-I documents those actions stemming from personal exchanges among employees within the organisation. It includes mutual assistance regarding environmental issues, helping others in undertaking environmental protection behaviours, and sharing with colleagues new sustainability related values. Although the adoption of OCBEs cannot be mandated, managers can encourage the emergence of OCBEs by shaping a supportive context through appropriate interventions (Boiral, 2009). In this respect, ‘green’ training can help to create favourable conditions for the emergence of OCBEs. Based on their survey results on ‘green’ HRM and OCBEs, Dumont et al. (2017) suggested that organisations should consider providing employees with adequate ‘green’ training, since training serves multiple purposes. ‘Green’ training helps to equip employees with the necessary awareness, skills, and expertise for the successful implementation of green goals. It also increases their awareness and cognition of EM and organisational green values. Indeed, thanks to the diffusion of environmental awareness and competencies, employees become better able to take suitable actions to mitigate the environmental impacts in the workplace. They adopt new ‘green’ behaviours that are not necessarily mandated in job descriptions or recognised by the formal reward system. Moreover, given their multidimensional nature, these actions can be directed to more than one subject, either toward the organisation or colleagues. Therefore, the following hypothesis is developed: Hypothesis 1. ‘Green’ training has a positive effect on employees' a) Organisation-focused OCBE (OCBEeO) and b) Co-worker focused OCBE (OCBE-I).