NATO Secretary-General Jens Stoltenberg
© javier soriano/Agence France-Presse/Getty ImagesNATO Secretary-General Jens Stoltenberg delivers his opening speech on Day 1 of the NATO summit at the Ifema center in Madrid.
NATO Secretary-General Jens Stoltenberg says the military alliance will commit to reaching net-zero greenhouse-gas emissions by 2050.

"NATO is determined to set the gold standard on discussing the security challenges of climate change," Stoltenberg said Tuesday in Spain's capital as world leaders arrived for two days of talks.

Stoltenberg says that NATO's immediate goal will be reducing the greenhouse gas emissions of its military forces by 45% by 2030.

He said climate change is "a crisis multiplier," so it matters for security.