Faculty and Staff

Michael Griffiths

Professor • Department of Environmental Science

I discovered my passion for climate science whilst an undergraduate (from the University of Wollongong, Australia) foreign exchange student at the University of Massachusetts (Amherst) in 2003-2004, where I was undertaking two graduate-level courses with renowned paleoclimatologist and ice-sheet modeler, Professor Robert Deconto. It was during this time that I also met Distinguished Professor Raymond S. Bradley, also a renowned paleoclimatologist, who introduced me to the diverse range of projects that his graduate and postdoc researchers were undertaking within the Geoscience Department’s Climate Center. Having conducted my undergraduate senior thesis in the Climate Center, at the completion of my exchange program I was offered a Research Assistantship to conduct my Masters with Prof. Bradley, and whilst doing so, garnered a strong interest in paleoclimatology, and particularly, the potential utility of cave records to inform us of climatic and landscape evolution in the near and distant past. As a result, for my PhD dissertation I sought to work on speleothems; following some lengthy discussions with numerous academics, I settled on a project (funded by the Australian Research Council to Professor Mike Gagan and Associate Professor Russell Drysdale) focused on improving our understanding of Indonesian environmental/monsoon evolution during the late Quaternary, and the factors responsible for the inherent changes in the karst landscapes, using stalagmites/flowstones from Flores. At the time in 2006, there was still much uncertainty as to the nature and causes of monsoon variability in Indonesia over glacial-interglacial cycles, and so by filling in some key spatiotemporal gaps in the proxy network, my colleagues and I were the first to establish the direct link between the deglacial rise in sea level and concomitant strengthening of the monsoon system (lead article published in Nature Geoscience in 2009). We recently extended this record back to ~31 kyr, and subsequently discovered some new and intriguing results that were published in Nature Communications in 2013. Most notably, we found that the Indo-Australian monsoon system played a key role in transmitting the well-documented deglacial climate perturbations in the North Atlantic to the Southern Hemisphere high latitudes via meridional shifts in the Intertropical Convergence Zone (ITCZ). These findings have shown to have important implications to our understanding of the sequence-of-events that lead to glacial terminations, because they demonstrate the pivotal role of the tropics, and in particular the ITCZ, in redistributing heat and moisture across the hemispheres. The next phase of this work has entailed exploring additional cave systems in Australasia so that a more detailed assessment of the regional behavior can be established over various time scales. For instance, I am currently collaborating on speleothem projects in Java (Professor Yair Rosenthal; Rutgers University), Laos (Professor Kathleen Johnson; UC Irvine), and China (PhD student Hongbin Zhang supervised by Professor Junhua Huang; China University of Geosciences) aimed at reconstructing shifts in regional atmospheric circulation and local water balance in Australasia through last glacial cycle and beyond.

Professional Interests

Broadly speaking, my research goals are focused on gaining a deeper understanding of how Earth's climate has changed in the past, and how we can use this knowledge to better predict future changes under an anthropogenic greenhouse gas-induced warming planet. More specific, my research involves using geochemical tracers preserved in sedimentary archives (including speleothems, lake sediments, fossil fish teeth) to reconstruct the geologic history (last approx. 100 million years) history of climate variability. 

I am particularly focused on building high-resolution and well-dated paleoclimate records—using stable isotopes (of C and O) and trace elements (Mg, Sr, Ba, P, U) as tracers for past environmental changes—to better understand the role of the tropics in global climate change over a range of time periods (e.g. glacial-interglacial, the Common Era). Whilst the environmentally-sensitive geochemical tracers preserved in cave deposits are primarily controlled by fluctuations in temperature, rainfall, and/or the overlying vegetation (above the cave), the underlying processes controlling the cycling of these tracers through the atmosphere, soil, and karst systems are extremely complex. Hence, my research employs a multi-pronged approach of combining modern cave drip-water studies and geochemical modeling, with the chemical and physical analysis of fossil stalagmites, to gain a deeper understanding of how these processes govern the isotopic and trace-elemental signals in the cave carbonate; understanding these processes is essential for robust environmental interpretations of the natural archives. I currently have ongoing projects in Australasia (China, Laos, Indonesia, Australia). In addition, I am also working on lake sediment and wetland projects based in NJ in collaboration with the NJ Department of Environmental Protection. Finally, I am working on a collaborative project involving the geochemical analysis of fossil fish/shark teeth from species covering the past approx. 100 million years, with the intent to reconstruct the paleobiology and paleoenvironmental history of various species and ocean basins respectively.  

Another key aspect of my research involves merging paleoclimate records with General Climate Model (GCM) simulations. Specifically, I am interested in using speleothems to help validate/improve the performance of GCMs, and in particular, assessing how well they simulate the Australasian monsoon systems over the past millennium. The GCM results are also being used to test different hypotheses regarding the mechanisms for past ocean-atmospheric circulation in Australasia.

Degrees

PhD Physical Geography, THE UNIVERSITY OF NEWCASTLE Newcastle, Australia

Specialization

Paleoclimatology/Geochemistry

No publications uploaded at this time.

Notable Courses Taught

General Geology (ENV1150); General Geology (summer session I, ENV1150-70); Oceanography (ENV2170); Global Climate Change (ENV3170); Junior Seminar (ENV3800); and Senior Practicum (ENV4800). I have also advised students for Field Experience (ENV3010) and Independent Study (ENV4990).