When you are comparing things you use comparative adjectives.
Examples: The landscape is dry. The landscape is drier.
For adjectives that end in ‘y’, change the ‘y’ to ‘i’ and add ‘er’.
It is warm. It is warmer in summer.
Adjectives made up of one syllable form the comparative by adding ‘er’.
It is exciting. Going to new places is more exciting.
All adjectives made up of two or more syllables form the comparative by the word ‘more’.
Example: Boring …….. more boring
For more help on comparative adjectives visit: http://www.learnenglish.org.uk/grammar/archive/comparatives01.html