General circulation models (GCMs) are complex computer simulations that are used to study and predict the global climate system. These models incorporate detailed representations of the atmosphere, ocean, land surface, and sea ice, and are used to simulate the interactions between these components in order to understand how they influence the Earth's climate. GCM simulations are used to study a wide range of climate-related phenomena, such as changes in temperature, precipitation, and sea level, as well as extreme weather events and long-term climate trends. These simulations can also be used to assess the potential impacts of human activities, such as greenhouse gas emissions, on the Earth's climate system. Overall, GCM simulations play a crucial role in advancing our understanding of the Earth's climate system and are used by scientists, policymakers, and other stakeholders to inform decisions related to climate change mitigation and adaptation.