Final answer:
The United States is currently a party to the Paris Agreement and the Montreal Protocol. It is not a party to the Kyoto Protocol but is a signatory to the UNFCC, which oversees the Paris Agreement.
Step-by-step explanation:
The international environmental agreements to which the United States is currently a party are the Paris Agreement and the Montreal Protocol. The United States is not a party to the Kyoto Protocol. Being a party to the United Nations Framework Convention on Climate Change (UNFCCC) is inherent to being a party of the Paris Agreement since the Paris Agreement is under the UNFCCC. The Montreal Protocol was adopted to address the depletion of the ozone layer, and the United States is a signatory to this treaty. The Paris Agreement, aiming to limit global warming and carbon emissions, was initially joined by the US, briefly exited under President Trump, but was rejoined by President Biden in 2021 with a commitment to significant emission reduction goals.