Washington ? Actress Sigourney Weaver is making her second trip to Congress in as many weeks, urging lawmakers to help oceans by reducing carbon dioxide emissions.

She made her pitch Thursday as a new report found that ocean chemistry is changing because more carbon is being absorbed into the seas from the atmosphere. The resulting increased acidity of the oceans poses a serious threat to shellfish and other marine life.

Weaver urged senators at a hearing to pass climate change legislation that would limit carbon emissions. She tells The Associated Press that she hasn’t felt more passionately about an issue. Senate sponsors of climate legislation are expected to unveil it Monday.

Ocean acidification has been dubbed global warning’s “evil twin.”