Those of us who still like to use an old-fashioned compass rather than GPS etc for navigation, either in the mountains or on the water, have always been accustomed to adjust the bearing for magnetic deviation: so that it's always been necessary to know the current deviation, specific to the location, between true north and magnetic north. Good topographic maps have always shown this, together with the anticipated average annual change from the date of publication: but of course this information soon becomes out of date. The advent of websites showing the current deviation for any location on the globe has therefore been very welcome. They're doubtless going to be very busy given this rapid change.
Incidentally I can see nothing in the report which claims this acceleration has anything to do with climate change.