The European Union climate commissioner, Wopke Hoekstra, said President Trump’s repudiation of climate action shows no signs of affecting other countries’ ambitions, including his own 27-country bloc.

“We’re doing the exact opposite of what the U.S. is doing, which, by the way, I find concerning and problematic,” he said in an interview in New York City. He described the actions of the Trump administration on climate as “basically checking out.”

But other big economies, he said, are continuing to step up their targets for reducing their emissions of planet-warming greenhouse gases. That will be put to the test on Wednesday in New York City, where the United Nations plans to host a climate summit at which 118 countries are expected to announce their 2035 emissions-reductions targets under the Paris climate accord.

That session could be a bit awkward for the European Union, given that its lawmakers haven’t yet finalized the E.U.’s 2035 climate targets. China is expected to announce its targets, which will be closely watched given the scale of China’s current emissions, but also its rapid embrace of solar, wind and battery manufacturing and its desire to pivot a significant part of its economy to clean-energy technologies.

In a speech on Tuesday to the U.N. General Assembly, Mr. Trump spent a portion of his 57 minute speech dismissing the dangers of climate change and lashing out at wind turbines, environmentalists and allies around the world.

The United States has said it will withdraw from the Paris accord, so it is not expected to participate in the U.N. climate summit this week or announce emissions-reductions targets of its own.