klimamodel

A klimamodel is a computational representation of the Earth's climate system that simulates the interactions among the atmosphere, oceans, land surface, cryosphere, and biosphere. Klimamodellen are used to understand past climate changes, attribute observed trends to natural and human drivers, and project future climate under scenarios of greenhouse gas emissions, solar variability, and land-use change.

Models range from simple energy balance models to comprehensive general circulation models. General circulation models solve fundamental physical equations for fluid flow, radiative transfer, and energy fluxes, primarily for the atmosphere and ocean. Earth system models extend GCMs by including biogeochemical cycles and dynamic vegetation. Regional climate models provide higher-resolution projections for specific regions.

Models are evaluated against historical data and used in multi-model ensembles to quantify uncertainty. They are driven by scenarios describing future emissions and land-use changes, yielding outputs such as temperature, precipitation, sea level, and projections of extreme events. These outputs support risk assessment, adaptation planning, and policy development.

Limitations include imperfect representations of complex processes, biases, finite spatial resolution, and uncertainties about future human actions. Parameterizations for clouds, convection, ice sheets, and the carbon cycle remain areas of active research. Interpreting results requires probabilistic framing and attention to natural variability and model spread.

Climate modeling has its origins in mid-20th-century meteorology and has evolved into integrated earth system modeling used in international assessments to inform policy and adaptation efforts.