Big banks are not best known for their ethical credentials. If there's money in oil, they'll invest in oil. They are not prone to jump on an ecological bandwagon because they feel sorry for orang-utans; they are not going to gamble their investors' money or their professional reputation on something that doesn't have a sound scientific backing.
In other words, if you were in any doubt as to whether climate change is real, you could do worse than follow the money. Deutche Bank have recently released a handy fat-wallet-sized paper that debunks the major 'climate skeptic' arguments. It summarizes: "The paper's clear conclusion is that the primary claims of the skeptics do not undermine the assertion that human-made climate change is already happening and is a serious long-term threat".