"Climatic changes in temperate latitudes that allowed the spread of grasslands." Grasslands are a habitat type, not a period of time. The remains of them have been preserved as fossils.
Spread of Grasslands
Grasslands Limited
"Grasslands limited". This is a microcosm of circular reasoning in two words. Whenever the remains of a grassland habitat is found fossilized it's assigned to something other than the Eocene.
Arid to Semiarid, Savanna Type Climates
The paleoenvironments of the periods of geological history that we're seen so far include a statement about climate as a way to rationalize why so much sediment would be eroded, transported and deposited.