Herweijer will leave to pursue new opportunities, the bank said, having played a pivotal role in shaping its climate policy.
Her role was cut from the bank's top decision making body, known as the group operating committee, as part of a wider reshuffle, Reuters reported on Oct. 29.
The move sparked concerns that the bank could row back on or water down some of its climate commitments under new CEO Georges Elhedery.
"With Celine’s departure, HSBC has lost a crucial moral compass in its journey toward net zero," said Andrew Harper, chief responsibility officer at Epworth Investment Management, a specialist investment firm serving UK charities and a shareholder in the bank.
Julian Wentzel, head of global banking for the Middle East, North Africa and Turkey region, will be interim group chief sustainability officer pending a permanent replacement, HSBC said.
The bank's replacement of Herweijer, an expert in climate and sustainability matters, with a banker albeit on an interim basis, could signal a "troubling shift in the bank's priorities," Harper said.
"Supporting the transition to net zero remains a priority for HSBC, and one of the four pillars of our business strategy," the bank said on Monday.
HSBC in January unveiled its first net-zero transition plan as part of its commitment to reach the target by 2050, laying out its aims to help the bank's heaviest-emitting clients decarbonise their businesses.
Lenders have pledged to spend trillions of dollars in an effort to help cap global warming but some of the biggest are saying that without clear policy direction from governments, it will be challenging to meet the goal.
HSBC also announced Richard Blackburn as the group's interim chief risk and compliance officer, pending a recruitment process to find a permanent candidate for a role that commands a place on the group operating committee.
Selim Kervanci, the bank's CEO for Turkey, was also appointed as its Middle East CEO, HSBC said.
