Final answer:
Greta Thunberg catalyzed a global climate change movement by starting with a solo protest outside of the Swedish parliament, leading to widespread student activism and recognition as Time's 2019 Person of the Year.
Step-by-step explanation:
Greta Thunberg took an important action that significantly impacted the global perspective on climate change. At the age of 15, she initiated a solitary protest outside the Swedish parliament, which rapidly evolved into a global movement, inspiring millions of students worldwide to partake in climate activism. Thunberg's activism includes speaking at international forums, inspiring school strikes for the climate, and receiving accolades such as Time's Person of the Year in 2019.