The Ministry for Ignoring Climate Change is set on the Echelon Quartet Islands, a fictional group of islands 'offshore western Canada'. Echelon was inspired by Haida Gwaii, a fact acknowledged for the sharp-eyed by the name itself—an anagram of its old colonial name, the Queen Charlotte Islands.
However the real Haida Gwaii, like many places in British Columbia and the Canadian arctic, have been affected by climate change, including changes to the salmon migration. One of the key events in the story, a community-led project to reverse the effects of climate change by the controversial practice of iron fertilization, was also inspired by real-life. In 2012 the community of Old Massett conducted an iron fertilization project which was criticized by many official organizations at the time. Some of the news coverage from the time is still available online here and here.
All the characters and locations in the story are however entirely imaginary, as are all the details and consequences of the experiment (to the best of my knowledge there is also no mysterious government ministry secretly planning for a warmer world, but you never know ...)
The above image of Windy Bay on Lyell Island, Haida Gwaii, is by Miles Green and is reproduced with thanks under a Creative Commons 2.0 license. The original is at https://www.flickr.com/photos/old_growth_trees/9670531054/