There isn't a one or two word direct equivalent in English...you could say "world changer" and people would know what you meant, but it sounds a little weird in English.

Are you looking just for the word, or is there some context it is in that might better help us to find the right translation?

The only two things I can think of right now are: do-gooder and humanitarian - it's past my bedtime :-)

Es geht um eine Personenbeschreibung.

Deutsch: Diese Person war ein wirklicher Weltveränderer!

phi·lan·thro·py
Pronunciation: \-pē\
Function: noun
Inflected Form(s): plural phi·lan·thro·pies
Etymology: Late Latin philanthropia, from Greek philanthrōpia, from philanthrōpos loving people, from phil- + anthrōpos human being
Date: circa 1623
1: goodwill to fellowmen; especially : active effort to promote human welfare
2 a: a philanthropic act or gift b: an organization distributing or supported by philanthropic funds

Then perhaps "philanthropist" or humanitarian would work.

Ein Weltveränderer ist etwas anderes als ein "Weltverbesserer".

Thomas Edison und Nikola Tesla waren Weltveränderer;

Alexander Bell und Philipp Reis waren auch Weltveränderer.

Weitere Weltveränderer: Columbus, Gutenberg, Napoleon, Karl Marx, Lenin,

Franziskus von Assisi, Benedikt von Nursia...

Sie alle haben - jeder auf seine Art - die Welt nachhaltig verändert.