On this Earth Day, government officials from around the globe are gathered at the UN headquarters in New York City to sign the historic climate change deal that was hammered out in Paris last December. This signing ceremony is one of several steps needed to put the global accord into effect.

Known as the Paris Agreement, the deal aims to limit global warming to 2°C (3.6°F) above pre-industrial levels. To achieve this goal, countries submitted individual five-year plans called “intended nationally determined contributions” or INDCs. They essentially spell out how much CO2 a country plans to cut based on its own political and economic situation. Under the current collection of national plans, however, the Paris Agreement will only cut greenhouse gas emissions by about half of what is necessary to reach the 2°C (3.6°F) goal. That said, the agreement does legally obligate countries to reconvene every five years to present updated plans detailing how they will deepen their emissions cuts.

The next step in the UN process requires participating countries to formally pledge that they will adopt the agreement within their own legal systems. The final step – known as “entering into force” – will happen when at least 55 countries, which together represent at least 55% of global emissions, adopt the agreement domestically. This last part is likely to take a few years.

A today’s ceremony, 155 countries are expected to sign the agreement.  This will set a new record for the number of signatories on an international accord. The previous record was held by the 1982 Montego Bay Law of the Sea agreement, which had 119 signatories.

Credit: UN