NSF Award
2103088
Humanity has undertaken an unintentional experiment on Earth’s climate system, causing atmospheric carbon to increase to levels never before experienced by humans. The climate system is now responding in palpable ways, and the triggering of positive feedbacks will accelerate changes, posing large risks to the biosphere in general and human populations in particular. Increasing concerns of potential runaway effects have spurred talk of intentional geoengineering to stabilize Earth’s temperatures, and its large ice sheets. A commonly discussed approach is solar radiation management (SRM), the intentional injection of atmospheric aerosols to mimic the planetary shading induced naturally by explosive volcanism. However, the unintended consequences of such action remain unknown, and could initiate even larger disruptions of the biosphere. This project targets an interval of Earth history analogous to today— a time with large continental ice sheets and abundant atmospheric dust followed by “greenhouse” warming— to explore how Earth’s climate and biospheric systems responded to sustained explosive volcanism. This research will test a number of hypotheses centered on the idea that frequent, explosive volcanism over the equatorial Pangean supercontinent ~300 million years ago increased delivery of micronutrients (e.g. iron) from atmospheric dust, leading to enhanced plant growth and development of widespread anoxia in marine ecosystems. Recent research documents large accumulations of dust deposits ~300 Mya, a remarkably elevated but enigmatic micronutrient content of these dusts, and abundant explosive volcanism, especially at equatorial latitudes. The confluence of volcanism, atmospheric dustiness, and nutrient reactivity is posited to have greatly affected Earth’s carbon cycle, and thus climate and biosphere. If society embarks upon intentional geoengineering, it is imperative to learn from Earth’s past to understand potential future consequences. In addition to shedding light on behavior of the climate system through publication and dissemination of results, this project will help prepare several students and early-career researchers for the STEM workforce, enhancing the nation’s capabilities in science and education.<br/><br/>This work explores novel aspects of climate-system behavior in two ways: 1— the role of repeated, high-frequency explosive volcanism in affecting Earth’s climate directly, and 2— linkages that tie explosive volcanism to enhanced nutrient release from mineral dusts and consequent ecosystem fertilization that affects the carbon cycle. To test this, field and laboratory work will be done on a well-exposed section of volcanic rocks representative of a vast center of volcanism in paleoequatorial Pangea; data will be collected on volcanic recurrence intervals and sulfur loading, and on the nutrient richness of coeval mineral dusts. These data will enable modeling of how this volcanism affected climate by both 1— direct “shading” of the planet, and 2— altering atmospheric acidity, stimulating micronutrient content of dust and thus fertilizing marine ecosystems. OU Geosciences and Science Education faculty will prepare and deliver long-term professional development for Oklahoma teachers, to increase climate science literacy amongst secondary school students.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
