Perhaps you feel bluster is appropriate for a discussion on climate and as artists these characters need no credentials. All that picture is is a few lines and colours, It isn't a graph. Perhaps it might be called a timeline but the squiggles have no meaning without a clearly identified ordinate scale.
The artists haven't published credentials on their website and you have provided neither a source for the colourful work of art nor any information on permission to republish the picture.
