During the final week that Credit Suisse Group AG existed as an independent entity, its chairman and chief executive took some time to pen remarks for the embattled bank’s sustainability report.

Axel Lehmann and Ulrich Körner provided their expectations for what Credit Suisse would look like in 2050. It would be—in their words—a cleaner, greener, more sustainable bank after having traversed the choppy waters of the energy transition and eliminated carbon emissions from its operations and financing activities.

As we now know, the Swiss lender, its leaders and their vision proved anything but sustainable. Indeed, now that the 166-year-old bank is in the process of being digested by UBS Group AG, the report reads like a user’s manual for an appliance that is no longer in production.

That’s not the end of the story, though. Just as UBS is sorting through Credit Suisse’s assets, properties and personnel, it’s also taking on its former rival’s carbon emissions. And that’s going to be an added burden for UBS, given its lower emissions profile.

“UBS is in a much better shape when it comes to sustainability and climate-risk performance, so adding Credit Suisse will certainly be a drag,” said Christoph Klein, founder and managing partner at ESG Portfolio Management, a Frankfurt-based asset manager with funds targeting sustainable outcomes. “They can harmonize ESG and climate policies quite easily, but improving the emissions profile of the acquired loans and investment portfolios might be costly and take time.”

Of course, it’s still early days. UBS chairman Colm Kelleher has acknowledged that the bank planned some consolidation as part of the deal. How much of Credit Suisse will be fully incorporated, or jettisoned, may remain unknown for some time. (UBS and Credit Suisse declined to comment.)

Part of the reason for Credit Suisse’s higher overall emissions is a function of its larger investment bank. UBS, having accepted a bailout from the Swiss government in 2008, made major cuts in investment banking in 2012 and retreated from capital-intensive trading businesses to focus on asset and wealth management.

That approach has meant fewer financed emissions for UBS relative to larger investment banks. It also probably means UBS now has less clout in pressing borrowers on their emissions-reduction plans.

“You can probably do more to influence climate action and the energy transition by hanging on to the capital markets and lending businesses,” said Harald Walkate, former head of environmental, social and governance investing at Natixis Investment Managers who’s now a senior fellow at the University of Zurich’s Center for Sustainable Finance.

To be sure, among European-based lenders, Credit Suisse had a so-called energy-supply banking ratio of 1.0 in 2021. This means it helped finance as much in clean-energy projects as fossil fuels, according to researchers at BloombergNEF. That ratio was better than rivals including HSBC Holdings Plc, Societe Generale AG and ING Groep NV.

That said, Credit Suisse hasn’t been doing enough to push for change, according to U.K. nonprofit ShareAction, which last year helped coordinate a shareholder resolution calling for the bank to devise and publish a robust plan for reducing its financing of fossil fuels.

Just last week ShareAction said the bank’s oil and gas policy is “one of the weakest” in the European banking sector.

For an enlarged UBS, its approach to emissions enabled from lending and debt underwriting will be critical to its future success, said James Vaccaro, who leads the Climate Safe Lending Network.

“The degree to which they show real leadership on climate and sustainability may determine how quickly they can build trust,” he said.