I mean if you had bothered to open the article, it’s in the 2nd paragraph:
The most comprehensive study of global climate inequality ever undertaken shows that this elite group, made up of 77 million people including billionaires, millionaires and those paid more than US$140,000 (£112,500) a year
Null at the SQL means that the value isn’t there, idk where you’re getting that from. SQL doesn’t have anything like JS’s undefined, there’s no other way to represent a missing value in sql other than null (you could technically decide on certain values for certain types, like an empty string, but that’s not something SQL defines).