The Collaborative International Dictionary of English v.0.48:

Intensification \In*ten`si*fi*ca"tion\, n.
   The act or process of intensifying, or of making more
   intense.
   [1913 Webster]

WordNet (r) 3.0 (2006):

intensification
    n 1: action that makes something stronger or more extreme
    2: the act of increasing the contrast of (a photographic film)

Moby Thesaurus II by Grady Ward, 1.0:

42 Moby Thesaurus words for "intensification":
   accelerando, acceleration, aggravation, amplification, annoyance,
   augmentation, beefing-up, blowing up, blowup, concentration,
   condensation, consolidation, contentiousness, deepening,
   deliberate aggravation, deterioration, embittering, embitterment,
   enhancement, enlargement, exacerbation, exaggeration, exasperation,
   explosion, heating-up, heightening, increase,
   information explosion, irritation, magnification, pickup,
   population explosion, provocation, redoubling, reinforcement,
   sharpening, souring, speedup, step-up, strengthening, tightening,
   worsening