Assertion: human's environment | /r/HasProperty | replaced by warmer climate
Facets:
value: gradually
type: MANNER
Source sentences:
text: The environment during this ice age period would have been a largely treeless tundra, eventually replaced by a gradually warmer climate, perhaps reaching 17 degrees Celsius (62.6 Fahrenheit) in summer, encouraging the expansion of birch trees as well as shrub and grasses.