One embodiment of a climate management topper includes a flowpath boundary which defines a flowpath adapted to carry a stream of fluid in a principal direction. A flow compliant filler occupies at least part of the flowpath. The filler is comprised of a spacer and a set of shape change actuators (SCA's) each comprised of a shape change material (SCM). The properties of the SCM include a critical temperature T0. The SCA's are configured to regulate distribution of the fluid stream through the flowpath in a direction transverse to the principal direction as a function of temperature. In one example the flowpath boundary is formed by liner panels and the SCA's are linear elements that elongate at a temperature TH which is higher than T0 thereby distending the spacer and reducing its resistance to fluid flow. One suitable shape change material is a nickel/titanium alloy known as NiTiNOL.