An email sent to Maren Costa, a principal user-experience designer at the company... warned that future infractions could “result in formal corrective action, up to and including termination of your employment with Amazon.”... “It was scary to be called into a meeting like that, and then to be given a follow-up email saying that if I continued to speak up, I could be fired... But I spoke up because I’m terrified by the harm the climate crisis is already causing... It’s our moral responsibility to speak up — regardless of Amazon’s attempt to censor us — especially when climate poses such an unprecedented threat to humanity”... Kowalski acknowledged receiving a similar letter from Sjoding but declined to comment on it... [A]fter an employee climate group emailed colleagues about the Sept. 20 walkout, Amazon updated its communications policy to create “a more streamlined and user-friendly way to request PR approval to participate in external activities”... The policy requires a “business justification” for any communications and notes that approval could take up to two weeks. [Emily] Cunningham, a user-experience designer, said she was informed in an October meeting with a human resources executive that she had violated the company’s recently updated policy... "It was a clear attempt to silence me and other workers who have been speaking out about the climate crisis"...