Final answer:
Paleoclimatology is the study of ancient climates, the IPCC is an international body that assesses climate change information, and a voluntary international accord refers to agreements to limit greenhouse gas emissions.
Step-by-step explanation:
Paleoclimatology: The study of ancient climates, specifically the changes in climate over geological time.
Intergovernmental Panel on Climate Change (IPCC): An international body established by the United Nations to assess the scientific, technical, and socio-economic information relevant to understanding climate change, its potential impacts, and options for mitigation and adaptation.
Voluntary international accord to limit greenhouse gas emissions: This refers to international agreements, such as the Paris Agreement, where countries voluntarily commit to reducing their greenhouse gas emissions in order to combat climate change.