Major atmospheric-driven catastrophes, such as hurricanes and floods, may appear to be independent events when looked at historically. Yet it is well established in climate science that regional weather and climate conditions in one part of the world can have impacts on other parts. It is important for insurers and reinsurers to know how interconnected climate drivers are as they are required by regulators to hold a level of capital that adequately reflects their exposure to losses from significant weather events. To establish whether the assumption of independence in insurers’ internal models is appropriate, this research investigates the extent of the links between different global extreme weather perils and the mechanisms for these dependencies. This report answers the question: is it reasonable to assume independence between significant weather risks in certain region-perils around the world?