  We analyze the thermodynamic response near extremality of charged black holes
in four-dimensional Einstein-Maxwell theory with a positive cosmological
constant. The latter exhibit three different extremal limits, dubbed cold,
Nariai and ultracold configurations, with near-horizon geometries AdS$_2 \times
S^2$, dS$_2 \times S^2$, Mink$_2 \times S^2$, respectively. For each of these
three cases we analyze small deformations away from extremality, and contrast
their response. We also construct the effective two-dimensional theory,
obtained by dimensional reduction, that captures these features and we provide
a more detailed analysis of the perturbations around the near-horizon geometry
for each case. Our results for the ultracold case in particular show an
interesting interplay between the entropy variation and charge variation,
realizing a different symmetry breaking with respect to the other two
near-extremal limits.
