It is convenient that climate has both a geological and psychosocial meaning, for the climate crisis humanity faces today involves both these domains and our ultimate environment as the Numinosphere, Satchitānanda, and Le Milieu Divin, in Pierre Teilhard de Chardin’s terms.
1375, climat ‘a zone of the Earth between two lines of latitude’, from Old French climat ‘region, part of the earth’, from Latin clima (genitive climatis) ‘region; slope of the earth’, from Greek klima ‘region, zone’, literally ‘an inclination, slope’, thus ‘slope of the earth from equator to pole’, from a suffixed form of PIE root *klei- ‘to lean’.
The more general meaning ‘a region of the Earth’ became used in reference to the region’s atmospheric conditions. This later evolved into the current sense ‘weather conditions of a region’.
The figurative sense of climate, as ‘mental or moral atmosphere’, entered English in the 1660s. Modern senses are, for instance, ‘prevailing influence or environmental conditions characterizing a group, period, or place; prevailing condition or set of attitudes, as a trend in human affairs’, as in climate of fear, climate of unrest, and political climate.