Answer the question from the given passage. Your answer should be directly extracted from the passage, and it should be a single entity, name, or number, not a sentence.

Passage: This projection was not included in the final summary for policymakers. The IPCC has since acknowledged that the date is incorrect, while reaffirming that the conclusion in the final summary was robust. They expressed regret for 'the poor application of well-established IPCC procedures in this instance'. The date of 2035 has been correctly quoted by the IPCC from the WWF report, which has misquoted its own source, an ICSI report 'Variations of Snow and Ice in the past and at present on a Global and Regional Scale'. Question: What did the IPCC say was mistaken?
the date