Swedish activist Greta Thunberg, 16, attends a protest outside the White House on Friday. She launched the Friday school strikes last year, and since then, her notoriety has steadily grown. She is known for speaking in clear and powerful terms about why people — particularly young people — must pay attention to Earth’s climate.

Swedish activist Greta Thunberg, 16, attends a protest outside the White House on Friday. She launched the Friday school strikes last year, and since then, her notoriety has steadily grown. She is known for speaking in clear and powerful terms about why people — particularly young people — must pay attention to Earth’s climate.