One corporate chief after another has been stepping onto the stage at a conference…to pledge allegiance to environmental causes…One of the more influential statements of the day may have come from Yngve Slyngstad, the chief investment manager of the world’s largest sovereign wealth fund, who outlined a gradual adjustment of the fund’s nearly $900 billion portfolio in response to climate change…Mr. Slyngstad, of the Government Pension Fund Global of Norway, said that the fund had already sold the stocks of companies like palm oil producers that were damaging tropical rain forests, and that he had rid the fund of all coal companies…Mr. Slyngstad’s moves are widely followed in the investment community because of the size of the fund…He argued against wholesale dumping of stocks, saying it was more worthwhile to try to work with companies in the portfolio to change them….