ECN’s data and expertise are relevant to a range of environmental policy issues including climate change, pollution and biodiversity loss. Long-term monitoring can inform policies and check how well they work.
As the period of time over which ECN data have been collected lengthens, so their value as evidence for policy increases. This was recognised in a Defra survey: "There are, however, data sets that have great potential strategically, for example the Environmental Change Network, but that need longer runs to deliver their full potential." 
ECN data provide an ecological baseline against which future changes can be judged
The value of ECN for informing policies has, of course, already been recognised. For example, a report for the Scottish Government stated “Research as part of the ECN and other upland catchments has already played an important role in shaping and monitoring the effectiveness of national and international policy on emission abatement strategies, for example in relation to atmospheric sulphur and nitrogen emission, deposition and impact assessments for the Gothenburg Protocol and its current revision.” . ECN data have also helped in the interpretation of land use change data collected by the Countryside Survey.