  Energy balance models (EBMs) are one- or two-dimensional climate models that
can provide insight into planetary atmospheres, particularly with regard to
habitability. Because EBMs are far less computationally intensive than
three-dimensional general circulation models (GCMs), they can be run over
large, uncertain parameter spaces and can be used to explore long-period
phenomena like carbon and Milankovitch cycles. Because horizontal dimensions
are incorporated in EBMs, they can explore processes that are beyond the reach
of one-dimensional radiative-convective models (RCMs). EBMs are, however,
dependent on parameterizations and tunings to account for physical processes
that are neglected. Thus, EBMs rely on observations and results from GCMs and
RCMs. Different EBMs have included a wide range of parameterizations (for
albedo, radiation, and heat diffusion) and additional physics, such as carbon
cycling and ice sheets. This CUISINES exoplanet model intercomparison project
(exoMIP) will compare various EBMs across a set of numerical experiments. The
set of experiments will include Earth-like planets at different obliquities,
parameter sweeps across obliquity, and variations in instellation and CO$_2$
abundance to produce hysteresis diagrams. We expect a range of different
results due to the choices made in the various codes, highlighting which
results are robust across models and which are dependent on parameterizations
or other modeling choices. Additionally, it will allow developers to identify
model defects and determine which parameterizations are most useful or relevant
to the problem of interest. Ultimately, this exoMIP will allow us to improve
the consistency between EBMs and accelerate the process of discovering
habitable exoplanets.
