Аннотация:Understanding the link between the greenhouse gas carbon dioxide (CO 2 ) and Earth's temperature underpins much of paleoclimatology and our predictions of future global warming. Here, we use the inverse relationship between leaf stomatal indices and the partial pressure of CO 2 in modern Ginkgo biloba and Metasequoia glyptostroboides to develop a CO 2 reconstruction based on fossil Ginkgo and Metasequoia cuticles for the middle Paleocene to early Eocene and middle Miocene. Our reconstruction indicates that CO 2 remained between 300 and 450 parts per million by volume for these intervals with the exception of a single high estimate near the Paleocene/Eocene boundary. These results suggest that factors in addition to CO 2 are required to explain these past intervals of global warmth.
