NERC - NSFGEO: Pliocene Lessons for the Indian Ocean Dipole (PLIOD)
Lead Research Organisation:
University College London
Department Name: Geography
Abstract
Climate patterns in the Indian Ocean impact freshwater availability for over a billion people. For example, large variability in the Indian Monsoon, either drought or extreme rain, can cause crop failure and massive harm to societies that rely on monsoon rains. With ongoing and future human-caused climate change, our ability to predict what will happen with the so-called 'vagaries' of the Indian Monsoon is challenging due to limited historical data and poor performance of current computer climate models for future climate projections [United Nations Intergovernmental Panel on Climate Change Sixth Assessment Report]. Increased climate extremes have been hypothesized via climate model simulations under future climate change scenarios, but additional research is necessary to ground-truth the underlying processes and mechanisms.
Using geological reconstructions of past climate together with climate model simulations will help us understand the underlying climate dynamics that drive the Indian Ocean under global climate change. Geologic evidence from 20,000 years ago, when the polar regions had large ice sheets, suggests the Indian Ocean had large climate extremes due to exposure of land mass around Indonesia and Australia. This shows the Indian Ocean is capable of switching to a climate state fundamentally different from today. However, we need to understand if this can happen during globally warm climates and identify the underlying mechanisms which may be different than globally cold climates. The mid-Pliocene warm period (~3 million years ago) is used as a pseudo-analog for future climate change because global temperatures were ~3oC higher than modern and atmospheric carbon dioxide concentrations were similar to our present day elevated levels. It is a key climate modeling target in the IPCC reports paleo-perspectives on climate change (Pliocene Model Intercomparison Project - PlioMIP) and paleo-data compilations (PAGES Working Group PlioVAR and United States Geological Survey PRISM). In this project, we will use state-of-the-art geochemical techniques and cutting-edge climate modeling [United Kingdom Earth System Model (UKESM1)] to reconstruct climate during the mid-Pliocene warm period. We will reconstruct the long-term climate evolution of the Indian Ocean over the last three million years and estimate climate extremity using novel statistical approaches. We propose a series of climate model simulations that will test the influence of high atmospheric greenhouse gas levels and altered land mass distribution.
Our proposed reconstructions will provide a transformative past climate perspective on the realism of projected future changes of the both average climate conditions and climate extremes. Our results would improve our confidence in future climate projections of Indian Ocean climate in future IPCC reports. This proposed work will push the frontiers of our understanding of the Indian Ocean's contribution to the global climate system and will benefit policy makers and aid in building communities resilient to future climate change.
Using geological reconstructions of past climate together with climate model simulations will help us understand the underlying climate dynamics that drive the Indian Ocean under global climate change. Geologic evidence from 20,000 years ago, when the polar regions had large ice sheets, suggests the Indian Ocean had large climate extremes due to exposure of land mass around Indonesia and Australia. This shows the Indian Ocean is capable of switching to a climate state fundamentally different from today. However, we need to understand if this can happen during globally warm climates and identify the underlying mechanisms which may be different than globally cold climates. The mid-Pliocene warm period (~3 million years ago) is used as a pseudo-analog for future climate change because global temperatures were ~3oC higher than modern and atmospheric carbon dioxide concentrations were similar to our present day elevated levels. It is a key climate modeling target in the IPCC reports paleo-perspectives on climate change (Pliocene Model Intercomparison Project - PlioMIP) and paleo-data compilations (PAGES Working Group PlioVAR and United States Geological Survey PRISM). In this project, we will use state-of-the-art geochemical techniques and cutting-edge climate modeling [United Kingdom Earth System Model (UKESM1)] to reconstruct climate during the mid-Pliocene warm period. We will reconstruct the long-term climate evolution of the Indian Ocean over the last three million years and estimate climate extremity using novel statistical approaches. We propose a series of climate model simulations that will test the influence of high atmospheric greenhouse gas levels and altered land mass distribution.
Our proposed reconstructions will provide a transformative past climate perspective on the realism of projected future changes of the both average climate conditions and climate extremes. Our results would improve our confidence in future climate projections of Indian Ocean climate in future IPCC reports. This proposed work will push the frontiers of our understanding of the Indian Ocean's contribution to the global climate system and will benefit policy makers and aid in building communities resilient to future climate change.
