To Jeremy Grantham, co-founder and chief investment strategist of the Boston asset manager GMO, the earth’s changing temperature is an investment imperative as well as a question of ethics.  “The climate is moving much faster than people think, and the responses are going to move much faster as well”, he says, arguing that measures to help polluters announced last week by the administration of Donald Trump may ultimately prove helpful.  “Doing his absolute worst will galvanise the response”, says Mr Grantham, a veteran investor whose current ideas include buying unloved copper miners for a world where cars are filled with electrical wiring, instead of combustion engines.  Such an approach might strike some as premature, and the veteran investor has form in being right, but too early, refusing to buy internet stocks long before the crash, for instance. Yet a US executive order designed to unwind efforts by the previous president to cut greenhouse gas emissions from power plants makes the question of timing unavoidable, even if it suggests policy may move slowly in the US highlights questions facing investors around the world: when, and how, should investors take climate change into account when deciding what to buy and sell?  For many asset managers and pension funds such long-term issues used to be shunted to teams responsible for developing policies on environmental, social and governance issues. Worthy, but perhaps peripheral for those paid according to investment profits.