They found that vertical co-ordination is usually addressed earlier in federal political systems than in unitary systems, but that this difference fades as national adaptation strategies are developed. These sub-national activities have been reliant on either sufficiently large internal financial resources, or on the ability to draw on external resources and information — for example, through climate change networks. While there is general agreement over many of the broad principles for efficient adaptation, there are a range of views about how those principles should be put into practice.