BRUSSELS — The European Union should follow scientific guidance, European Commission Vice President Teresa Ribera told POLITICO after the bloc’s climate advisors criticized Brussels’ plans to weaken a critical climate target.

The EU’s scientific advisory board on climate change on Monday warned against using international carbon credits to meet the bloc’s 2040 emissions-reduction goal, saying doing so would undermine the EU’s climate credibility.

Climate Commissioner Wopke Hoekstra has floated carbon credits as an option to give member governments leeway on the 2040 target, which the EU executive wants to set at 90 percent below 1990 levels. His proposal is expected on July 2.

While Ribera did not address carbon credits directly, she suggested the EU should follow the board’s advice — comments that hint at divisions between her and Hoekstra.

“The data provided by science is not negotiable,” she told POLITICO.

“Our duty is to find the most straightforward and economically viable path to reach our goals — without ever losing sight of our ultimate objective: to stop dangerous climate change. It’s not enough to feel reasonably comfortable just because we’re doing something.”

The board’s report, she added, “shows that there is still much to be done, and the task won’t be easy. But facing the consequences would be far harder if we chose to ignore the true scale of the problem.”

Ribera, the Commission’s vice president for climate and competition issues, oversees the work of Hoekstra, who is in charge of drafting the 2040 proposal. The two commissioners come from competing political families — Ribera from the center-left Socialists, and Hoekstra from the center-right European People’s Party.

In an interview with POLITICO last week, Ribera declined to endorse or reject carbon credits, which let one country pay for emissions-slashing projects abroad and deduct the CO2 cuts from its own tally.

She confirmed that the target would be set at 90 percent with “flexibilities” on how to meet it, but cautioned against excessively watering down the bloc’s domestic emissions-reduction efforts.

At one point she said: “We need to comply formally with our obligations, including 90 percent domestic.” The 2040 goal, she added, had always been “conceived as domestic,” given that the bloc’s legally binding 2030 and 2050 climate targets explicitly refer to EU-based emissions cuts.

The advisory board on Monday reiterated its recommendation for a 2040 target of 90 percent to 95 percent, a figure “expressed in domestic terms.”

Hoekstra reacted to the report with a post on X on Monday, writing: “The latest advice from the independent [board] is clear: a competitive, resilient, secure and sustainable Europe depends on ambitious climate policies. That means both cutting emissions and adapting to our already changing climate.”

His spokesperson declined to comment further.