The continued release of fossil fuel carbon into the atmosphere today means it is imperative to understand Earth system response to CO2 rise, and the geologic record offers unique opportunities to investigate such behavior. Stomatal and paleosol proxies demonstrate a large change in atmospheric pCO2 across the Triassic-Jurassic (T-J) transition, concomitant with the eruption and emplacement of the Central Atlantic Magmatic Province (CAMP) and the splitting of Pangea. As one of the “big 5” mass extinctions—when the so-called modern fauna was particularly hard hit—we know the biosphere was severely affected during this time, but the details are relatively poorly understood, particularly with respect to an Earth system perspective. As part of the NSF Earth Life Transitions initiative, our team has targeted the T-J for integrative investigation to explore, among other things, alternative ecological states that may exist in the aftermath of mass extinctions. The initial findings reveal a global “sponge takeover” in the Early Jurassic following the extinction that lasted nearly 2 million years. The sponge takeover may be linked to an unusual confluence of factors, including potential ocean acidification and intense silicate weathering following the emplacement of CAMP.