This is the 797th most frequent Korean word.
변화가
"변화가" means "a person who brings change" or "a reformer."
Here, '변화가' is the subject and is used to indicate change in the climate, a natural phenomenon.
최근 몇 년간 기후 변화가 심각해졌습니다.
The climate change has become severe in recent years.
In this sentence, '변화가' serves as the subject and denotes a change in someone's personal behavior or attitude.
그의 태도에 긍정적인 변화가 보였습니다.
A positive change was observed in his attitude.
'변화가' here is also the subject, describing a broad transformation in technology.