Scientists have discovered a peculiar process within horsetail plants that could revolutionize our understanding of ancient Earth's climate. As water travels through these plants' stems, it undergoes a unique transformation, leaving behind valuable isotopic signatures. By analyzing these signatures in fossilized horsetails, researchers can gain insights into past environmental conditions, including temperature and water availability. This innovative approach offers a new tool for reconstructing ancient ecosystems and understanding how climate has changed over geological time scales, potentially informing our understanding of current climate change impacts.