By Jennifer Hiller

Exxon Mobil Corp shareholders soundly rejected climate-related proposals and splitting the chairman and chief executive's roles at the oil major's shareholder meeting on Wednesday.

Climate activists had swung behind efforts to split the roles of chief executive and chairman after prior defeats on resolutions seeking to make it more accountable to shareholders on climate change risk. This year's vote on an independent chair collected 32.7% of the vote, down from nearly 41% last year.

Exxon's director slate was approved by an average of 93.6%, the company said in preliminary results.

Influential proxy adviser Institutional Shareholder Services this year recommended a vote against the independent chairman resolution.

That was enough to overcome support for the measure by Exxon's second-largest shareholder, BlackRock Inc, which said it voted in favor of an independent chairman and against the re-election of two directors over the company's approach to climate risks.

Matrix Asset Advisors voted in line with ISS because it has no major issue with Exxon management, said President David Katz. "Nothing has risen to the level where we have to step in and make our voice heard," Katz said.

Exxon had taken steps to bolster its defenses against the measure by granting its lead director increased authority. The proposal last year received nearly 41% of the vote.

Unlike European rivals, Exxon faces little government pressure to curb greenhouse emissions or strike deals with climate activists. Under CEO Darren Woods, it blocked six climate resolutions from this year's ballot, encouraging activists to seek the split.

Other shareholder proposals that failed included calls for the company to increase its reporting of lobbying, political contributions and petrochemical risks, and to make it easier for shareholders to call special meetings.

Top Exxon holders' Vanguard Group and State Street Corp declined to comment on their votes. With BlackRock, the three combined own about 20% of Exxon shares.

(Reporting by Jennifer Hiller in Houston; Editing by Bernadette Baum, Marguerita Choy and Tom Brown)