This thesis focuses on corporate governance, climate change mitigation, corporate carbon performance, sustainability practices, biodiversity disclosure, and financial performance of top global companies. It consists of the introductory chapter, three empirical papers, and the concluding chapter. The first paper examines the relationships among process-based corporate climate change initiatives (PCCCIs), outcome-based corporate carbon performance by emissions (OCCPE), and market value (MV) and investigates the moderating role of a board sustainability committee (BSCOM). The results reveal that higher levels of greenhouse gas (GHG) emissions are negatively associated with MV, whereas PCCCIs are positively related to MV. The results also show that the presence of BSCOM has a positive impact on MV, but does not seem to improve OCCPE. Further, the findings indicate that increased levels of GHG emissions have a positive relationship with PCCCIs, and this relationship is reinforced by the presence of BSCOM. The second paper investigates the effects of climate change innovation (WCCIN) and sustainability reporting practices (SRPR) on the level of biodiversity disclosures (WBDDE) and tests whether corporate governance quality (CGOVQ) and actual carbon performance by emissions (ACCP) influence these impacts. The results show that greater commitment to WCCIN and improved SRPR are positively associated with WBDDE. The results also reveal the moderating effects of CGOVQ and ACCP on the WCCIN—WBDDE and SRPR—WBDDE links differ between the United Nations members that ratified the Convention on Biological Diversity and the USA that did not ratify. The third paper explores the impact of board gender diversity (BGEND) on corporate carbon emissions (CPEMS) and investigates whether a board-level policy on gender diversity (PBGEN) moderates this relationship. The results show that BGEND results in a significant reduction of CPEMS. Further, the results suggest that the negative impact of BGEND on CPEMS is intensified when PBGEN is present. From the critical mass perspective, the findings also suggest that corporate boards should consist of at least two female directors to reduce CPEMS. Finally, the findings reveal that the relationships among BGEND, PBGEN, and CPEMS differ among countries with gender quotas, countries with governance codes, and countries without quotas and codes.Keywords: Corporate governance, climate change initiatives, financial performance, sustainability practices, biodiversity disclosures, and carbon performance.