The politicians who implemented a Carbon (dioxide) tax in Australia have learned that talking about global warming to get votes and doing nothing about it is by far a safer option. They lost the government and now their precious tax too.
Since about 1976 the areal extent of sea-ice in the Northern Hemisphere has varied about a constant climatological level but in 1972-1975, sea-ice extent was significantly less - IPCC 1990 assessment, Page 224.