IPCC colour scheme for the RCPs

For those who work with the RCPs (the Representative Concentration Pathways), it seems like colour schemes should be simple. Same set of simulations – same colours. Easy. But it’s not – almost every paper I’ve read uses a different set of colours.

So… the IPCC report (WG1) should have sorted this out. It did, mostly. *Most* of the plots use this scheme:


RCP2.6 RCP4.5 RCP6.0 RCP8.5
Hex #0000FF #79BCFF #FF822D #FF0000
RGB 0 0 255 121 188 255 255 130 45 255 0 0
Looks like: Royal Blue Light Blue Orange Red


It’s provided here for your convenience in hexadecimal and RGB.

You might not like the colours they used. Like me, you might think that the use of the same diverging colour scheme for maps and RCPs alike is a bit controversial (given the non-linearity of almost anything that’s not watts per meter squared in the RCPs). But maybe, hopefully, we can all accept and use this colour scheme for plots and publications using the RCPs. It makes it so much easier for the reader. And we can do something more productive with our time than puzzle over which colour scheme to use. (I am a big fan of colorbrewer for this purpose.)

Hat tip to Ed Hawkins for helping me with this.