Understanding the environmental factors controlling the origin and shifting abundance of C4 grasses in Earth’s history is useful for projecting the response of C4-dominated grasslands to future environmental change. Unfortunately, grass pollen is typically morphologically indistinct, making pollen-assemblage analysis a blunt tool for studying C4-grasses in the paleorecord. The lab has lead the development of a new technique called SPIRAL (Single Pollen Isotope Ratio AnaLysis) for distinguishing morphologically indistinct grains of C3 and C4 grass pollen in the paleorecord. The lab is using this tool, in collaboration with colleagues throughout the world, to help to address long-standing questions about the ecology and evolution of grasslands.