This report provides a broad and evidence-based analytical perspective of the debate around the possible role of a Border Carbon Adjustment (BCA) to deal with climate change. The new context of divergent climate ambition has led to a resurgence of interest in BCAs. The paper provides an overview of different policy instruments that can limit carbon leakage, with a particular focus on the BCA option, and offers a technical review of the literature and of the legal specificities around BCA as well as of alternative instruments. The report also analyses the issue of fragmented climate policies in the broader perspective of the trade-climate nexus and discusses how other policy measures – especially those related to trade – can help support climate objectives (for example, reducing the existing barriers to trade in environmental goods, and removing environmentally harmful and trade distortive subsidies).