The Allen Institute operates more like a product-driven start-up than an academic lab whose students are focused on research suitable for peer-reviewed publications.
To accept a role for grey literature at the IPCC, provided it is properly and critically assessed by the authors, is not to say that peer-reviewed publications should not dominate the assessments.
Towards that goal, OSTP last week released two Requests for Information (RFI) soliciting public input on long term preservation of and public access to the results of federally funded research, including digital data and peer-reviewed scholarly publications.
In its 120 pages, Weathering Uncertainty references 280 publications from the scientific literature (peer-reviewed and grey) and covers themes at the core of the Fifth AR such as foundations for decision-making on indigenous knowledge, traditional livelihoods, vulnerability, resilience, and adaptation policy and planning.