3. Section 172(1)(a) of the Fair Work Act 2009 (Cth) provides that an enterprise agreement can only validly deal with "matters pertaining to the relations between each employer that will be covered by the agreement and its employees." Bob a union official for a construction union who is a strong advocate of reducing carbon emissions by the industry as he is concerned about climate change. He wants to know if he can include a clause in the enterprise agreement which obliges employers to commit to zero emissions target by 2030. Advise Bob whether this will be lawful under 172(1)(a) of the Fair Work Act 2009 (Cth)