By Charlie Conchie BlackRock said it had raised $4.5bn (£3.97bn) for a new climate infrastructure fund today as it looks to ramp up investment in the net zero transition amid criticism of its decision to continue backing oil and gas firms. The world’s biggest asset manager, which has around $8tn under its stewardship, said it had secured backing from public and private pension funds, sovereign wealth funds, insurance companies and family offices for the new fund – Global Infrastructure Fund IV. The investor is set to target five sectors with the new capital – energy, low carbon power, transpor…