Yes, there is. It is called universal human rights, and it was invented by Zoroastrians (based on the ethics of Zarathushtra himself, and his idea that diversity and pluralism are sacred and should be encouraged and not fought against). Cyrus The Great formulated these rights for the first time in history (a copy of them written on a cylinder can be found at the entrance of the United Nations building in New York) when he conquered Babylon.
Cyrus reportedly not only thought and spoke tolerance, he also practiced it, as a proper Zoroastrian should. The first thing Cyrus did after conquering Babylon was to enter the Temple of Marduk, the highest of the Babylonian gods, and kissed the feet of the statue of Marduk. He also consequently set the Jewish people, trapped in Babylon, free, sending them back to Palestine, with the explicit order to rebuild their temple and follow THEIR OWN RELIGION when doing so. Universal human rights is consequently at the heart of Zoroastrian ethics!
Is there anything called Global Ethics that be followed by all people? How would it be applied to cultural relativism or ethical relativism?