The most common and most likely answer to this crossword clue is the 7 letter word UNFROZE
I've seen this crossword clue in The Guardian
U
N
F
R
O
Z
E
More clues leading to the result UNFROZE
Buddy explains!
The straight part
We know that "reacted to global warming" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case reacted to global warming = unfroze.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does UNFROZE mean?
UNFROZE verb- To defrost something.
- To thaw.
- To resume movement.
- To release from a previously locked or frozen state.