Q:

What are the top 21 meetings regarding climate change?

I was at an academic conference recently and one of the presenters mentioned examining certain variables before and after the top 21 climate change meetings.
Unfortunately I was not able to get a hold of her after the conference and I have no background in earth science/climate change. Does anyone know what she could have been referring to?
I am aware of the COP and CMP only held by the UN.

A:

As Isopcycnal Oscillation has noted in the comments, you've probably misheard, and what they were talking about was COP 21 (not "top 21"), the 21st summit of the UNFCCC parties in Paris, December 2016.

