It’s just the next step in the denial. Once “it’s happening” becomes transparently silly to deny, the next step is “fine, it’s happening, but we can’t do anything”.
Hold on, what evidence do you have that Lomborg ever held that first position? I've run into interviews with him since forever and remember his position has having been very consistent: climate change is real but not an existential threat and we should be more rational in prioritizing our responses to it. Or something like that.
