The international treaty which provides operational rules on reducing greenhouse gas emissions is called:

Paris climate agreement of 2015

Explanation:

In the year 2015, global leaders seeking to join forces to combat the ever increasing emissions of green house gases which is having a bad influence on our prevailing world climate met in Paris in 2015, although the treaty became effective in the year 2016.

There are 195 signatories to the treaty. The Paris Agreement's long-term temperature goal is to keep the increase in global average temperature to well below 2 °C above pre-industrial levels; and to pursue efforts to limit the increase to 1.5 °C, recognizing that this would substantially reduce the risks and impacts of climate change.