text: For the climate change discourse, the second-largest cluster (34%) is indicated in red and focuses 
  on the responsibility to tackle climate change, where several global action hashtags are included, such 
  as “un”, “parisagreement”, “cop21”, and “cop24”. The theme of the third largest cluster (20%) in 
  the climate change discourse was energy (in blue). The smallest cluster (6%) in yellow sits in the 
  central part of the network with a mixed theme composed of three highly ranked hashtags, including 
  “environment” (No. 2), “climateaction” (No. 3), and “energy” (No. 6). 