Swedish teenage climate activist Thunberg turns 18

Activist Greta Thunberg gestures in a photo which was posted with a message thanking her supporters for their well wishes for her 18th birthday, in this undated picture taken from social media. @GretaThunberg/via REUTERS

(Reuters) - Sweden's Greta Thunberg, who pioneered a global climate change campaign as a 15-year-old, turned 18 on Sunday and promised to celebrate by exposing "dark secrets" at her local pub.

"Thank you so much for all the well-wishes on my 18th birthday!," Thunberg said on Twitter.