LONDON — In July, the opera director Peter Sellars gave a stark speech about climate change to open the Salzburg Festival in Austria, one of classical music’s most glittering events.

“We are today facing leadership across the world,” he said, “that is willing to sacrifice the next generation and the generations after that.” People everywhere, he added, had to “shift out of bad habit energies and make basic, common-sense changes in our lives.”

That night, he unveiled his new production of “Idomeneo,” which turned Mozart’s opera into a climate change parable and featured a dancer from Kiribati, an island nation threatened by rising sea levels.

Less than three months later, on Oct. 3, Helga Rabl-Stadler, the festival’s president, traveled to St. Petersburg to sign a new sponsorship deal with Gazprom, the Russian energy giant, and OMV, an Austrian oil and gas firm. The companies will each pay 200,000 euros (about $220,000) toward staging a Russian opera at next year’s festival.