Adaptation of emerging computational technology for carbon and palaeoclimate modeling

One of the grand challenges to human civilization is man-made climate change, much of which is caused by the burning of fossil fuels that releases CO2 to the atmosphere. Current research in climate science is aiming to better understand the relationship between natural changes of atmospheric CO2 levels and natural climate change over the long course of Earth's history. Reconstructions based on sediment cores recovered from the deep ocean demonstrate that over the last ~50 million years Earth's climate has unsteadily transitioned from warm "greenhouse" conditions with no ice in Greenland and Antarctica to the modern "icehouse" state with continental-scale ice caps near the poles. Other types of measurements on these deep sea sediments indicate that atmospheric CO2 levels and ocean acidity have broadly declined over the same timeframe, thereby raising the possibility that atmospheric CO2 decline may have been a key reason for ~50 million years of global cooling. The central aim of the work proposed here is to improve our understanding of the role of atmospheric CO2 in regulating the state of the climate system.

Because of the complexity of the involved physical, chemical and biological processes computer models have become a central tool in climate research. Considering the vastness of our planet and the many million years of Earth history, it becomes clear that Earth System modeling is a computational challenge that requires the use of ever-faster supercomputers. The greatest change in high-performance computing over the last decade and the foreseeable future is the development of "General Purpose computing on Graphics Processing Units" (GPGPU), which greatly reduces the size and energy consumption a given computer needs to do a given calculation in a given amount of time. Thus, within the limited space and power supply of a building that houses a supercomputer much larger computational problems can be solved using GPGPU rather than the classical approach that relies on CPU (Central Processing Unit) hardware. However, the existing Earth System models were developed for CPU-architectures and are therefore unable to fully exploit the benefits from GPGPU. The approach of the work proposed here is to develop GPU-native model components (marine biology, chemical mixing by physical ocean circulation, CO2-exchange between ocean and atmosphere, etc.) that enjoy the full computational benefit from GPGPU. This aspect of the work builds on the collaboration of and the exchange of knowledge between scientists in the fields of high-performance computing and the Earth sciences.

Ultimately, a better understanding of Earth history and climate change must be derived from reconstructions based on the sedimentary record as evidence. These observations are frequently compared to model simulations as a way of verifying that a particular simulation is in agreement with data of different types. With the work proposed here it will become possible to systematically compute thousands of simulations, followed by meticulous comparison to observations. Based on this advance, the cross-comparison between data and models (and between data and data) will help to better understand how the Earth System has changed in the past, and what were the driving processes. This knowledge of the past will then inform our outlook for the climate and the carbon cycle of the future.

Academia, the public sector, NVIDIA Corporation (and other industry stakeholders), the education sector, and the general public will benefit from the proposed research program as listed below. For details on the various items (A1-3, B1-2, etc.) of the Impact Plan refer to the Pathways to Impact section.

Academia, in general and in the UK in particular, will benefit through (A1) the creation of knowledge, and (A2) knowledge exchange mediated by the multidisciplinary nature of the proposed work. The project will facilitate (A3) cross-disciplinary knowledge transfer via the adaptation of GPU high-performance computing technology by the Earth science research community. The interdisciplinary panel of collaborators will serve as a forum to explore how these different fields can work together to yield a better understanding of the Earth System and its physical, chemical and biological components. Technology transfer and knowledge exchange will be further enhanced by two stakeholder workshops and one weeklong GPU training course hosted by Hain (part of A2-3). As part of the project, a powerful workstation equipped with three discrete Tesla K20 GPU compute accelerators will be installed and maintained at the National Oceanography Center Southampton (part of A3).

The public sector will benefit (B1) on a national and international level through the core scientific objective of this proposal, which is to further the understanding of the coupling between climate and the carbon cycle. The knowledge that is to arise from this work will be relevant to ongoing international negotiations with the aim to curb man-made global change of the climate and the environment. Furthermore, the public sector will benefit (B2) on a national level by gaining detailed knowledge about future strategic requirements for UK high-performance scientific computing needs. This information will be provided to the UK public sector via collaboration with the STFC.

NVIDIA Corporation is a formal collaboration partner on this proposal via the NVIDIA Academic Partnership Program. They provide hardware, software and technical advise in exchange for (C1) detailed feedback on how their technologies can be useful for fundamental research. Moreover, NVIDIA and other high performance computing companies will benefit through (C2) access to the scientific community and public sector representatives at the stakeholder meetings.

Students will directly benefit through Hain's participation in the (D1) "Learn with US" program of the University of Southampton. The education sector in general, both students and educators, will benefit through online content created and disseminated as part of this projects outreach avenues. Specifically, students and prospective scientists will benefit from (D2) a dedicated outreach website that providing information on how to get involved with climate science and Earth System research. Educators will benefit through (D3) the expansion of the free "Nature Education Knowledge Project" offering of educational resources.

To ensure the broadest possible impact of the project, the general public will be engaged through (E1) online channels such as Facebook, Twitter and online blogs, as well as Hain's participation in established channels of outreach at NOCS, such as (E2) participation in the annual NOCS "Ocean and Earth Day".