Using digits within lyrics

[John or Jan Lahr]

I want to include the digit 2 within the lyrics of a song.
The music currently has:

but I would like to have:  "C O 2 and N 2 O"

What change would I need to make to my current input file?

Thanks,
John

\paper {
  linewidth = 9.0\cm
  vsize = 10.0\cm
}
}
\layout {
   indent = 0.0\cm
}
 
     \version "2.9.13"
     melody = \relative c' {
        \clef treble
        \key c \major
        \time 4/4
     
  e8 e8 e8 e8 e8 e8 e8 e8 
  c8 c8 d8 d8 a4    f'4~f8 
     c8 c8 c8 e8 c8 c8 g8
  c8 d4    e8~e2 
     e8 e4 e8 e8 e8 e8 e8
  c'8 c8 b8 b8 a2 
  r8 \relative{ e8 e8 e8 e8 e8 e8 e8
  a1 
  r8 g8 g8 a8 e4 (d4)
}

     }
     
     text = \lyricmode {

        

\set
stanza = "2. "

        

C O Two
and N Two O and e -- ven N H Four

        

cause our
pre -- cious po -- lar ice to melt a -- way.

        

O -- ceans
will rise, low -- ly -- ing lands will dis -- ap -- pear.

        

It's not
too late to save the day, no time to waste.
        
     }
     
     \score{
        <<
           \new Voice =
"one" {
             
\autoBeamOff
             
\melody
           }
           \new Lyrics
\lyricsto "one" \text
        >>
        \layout { }

        

\midi {
\tempo 4=128 . = 128 }
     }