  New and archival interferometric 12CO(1->0) datasets from six nearby galaxies
are combined with H_2 2.122um and H-alpha maps to explore in detail the
interstellar medium in different star-forming galaxies. We investigate the
relation between warm (H_2 at T~2000 K) and cold (CO at T~50 K) molecular gas
from 100 pc to 2 kpc scales. On these scales, the ratio of warm-to-cold
molecular hydrogen correlates with the fnu(60um)/fnu(100um) ratio, a ratio that
tracks the star formation activity level. This result also holds for the global
properties of galaxies from a much larger sample drawn from the literature. The
trend persists for over three orders of magnitude in the mass ratio, regardless
of source nuclear activity.
