Is it $8.5 million of BHP’s shareholders’ money wasted on a directors’ virtue-signalling frolic to further their climate change credentials and justify the existence of a corporate vice-president for Sustainability and Climate Change? Or, as the New York Times suggests, a necessary response to mounting pressure from activist shareholders (including the politically-oriented industry superannuation funds)? Or is it simply a good investment in a potentially significant technological advance that could offset the huge CO2 emissions resulting from BHP’s role as the world’s largest mining company.