Html code? Hyper-text markup language, it basically is what websites are made up of, you enter an html code to create one. It is easier to use web design sites though

HyperText Markup Language is the standard markup language used to create web pages.

https://en.wikipedia.org/wiki/HTML

Not sure why this is in global warming.

HTML is the programming language that makes websites. It has nothing to do with global warming.

"hyper-text mark-up language" is the 'html' abbreviation.

thank you