Attendance numbers at a COP vary greatly.  Normally, the range is from 3,000-10,000 people, however at key moments in the negotiation that number can jump drastically.  For example, COP21 in Paris had 28,187 official participants (parties and observers) in attendance.  This only counts those officially registered, in actuality, the numbers can be much higher, as many people attend on the sidelines and do not access the official negotiation zone.  For Paris, the overall attendance was estimated to be 40,000 people.
 

Only countries that are a party to the agreement can participate in official negotiations, all other countries and members of broader society participate as observers.  Each country that is a party to the agreement sends an official negotiation team that is often made up of many actors from the country including elected officials, government staff and key members of society, sometimes this includes youth representation (depending on the decision of the country).

There are several “Constituencies” to the UNFCCC.  These are loose groups of NGOs with diverse but clustered interests or perspectives. These groups are not parties to the agreement but may have official roles in the negotiations, such as making interventions during sessions or providing written input, called submissions, on views and information on various issues under negotiation. These include:

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• BINGO - Business and Industry NGOs

• ENGO - Environmental NGOs

• Farmers - Farmers and agriculture NGOs

• IPO - Indigenous peoples organizations

• LGMA - Local government and municipal authorities

• RINGO - Research and independent NGOs

• TUNGO - Trade union NGOs

• WGC - Women and gender constituency

• YOUNGO - Youth NGOs

In addition, the UNFCCC secretariat also recognizes the following groups as informal NGO groups:
 

• Faith Based Organizations (FBOs)

• Education and Capacity Building and Outreach NGOs (ECONGO)

• Parliamentarians

To learn more about the constituencies visit the UNFCCC site here.