They also charge more to take on the additional risk associated with the loans that they provide. The terms for the loans may also be more restrictive. For instance, loans to small businesses may often be small relative to the size of the business, or require collateral or personal guarantees.
The second challenge is a lack of expertise. The relevant analytical knowhow is rare, as this topic has not been included in the mainstream economics or finance curricula in the universities. So far, basically everyone within the central banking community involved with climate has had to study the issue for themselves.