This Practice Note provides details on climate change and sustainability issues facing the financial sector, including issues relating to biodiversity and nature. It provides an introduction to the area, setting out why climate change and sustainability is such a hot topic and explains how that has affected the financial sector especially when dealing with risk and financial stability. The Practice Note provides information on the global and European policy and legislative initiatives in this area, such as the Paris Agreement 2015, Sustainable Development Goals (SDGs), Principles for Responsible Investment (PRI), Principles for Responsible Banking (PRB), Task Force on Climate-related Financial Disclosures (TCFD), Task Force on Nature-related Financial Disclosures (TNFD), Regulation (EU) 2019/2088 on sustainability-related disclosures in the financial services sector (SFDR), Regulation (EU) 2020/852 on the establishment of a framework to facilitate sustainable investment and amending Regulation (EU) 2019/2088 (Taxonomy Regulation) and Regulation (EU) 2019/2089 amending Regulation (EU) 2016/1011 as regards EU climate transition benchmarks, EU Paris-aligned benchmarks and sustainability-related disclosures for benchmarks (Low Carbon Benchmark Regulation). Policy developments, alongside regulatory and legislative measures in the UK level are also covered, as well as developments from key authorities such as the Prudential Regulatory Authority (PRA).