"Leaving the saving of our planet to our children is utterly unfair. @GretaThunberg, you're an inspiration. There are no excuses now. We owe the future generations a safe planet. The time for change is now," Sharma tweeted on Tuesday.
Thunberg started her speech saying, "this is all wrong".
"You have stolen my dreams and my childhood with your empty words. We are in the beginning of mass extinction and all you can talk about is money and fairy tales of eternal economic growth - how dare you," Thunberg said at the UN Climate Change Summit.
In her UN speech, the activist furthur said, "I shouldn't be here. I should have been back at school, on the other side of the ocean. Yet you all come to us young people for hope. How dare you?"
"For more than 30 years, the signs have been crystal clear. How dare you continue to look away and come here saying that you are doing enough when the politics and the solution needed are still nowhere in sight," she added.