The 'How' and 'Why' of climate change and its impact on society, landscapes, and ecosystems, are my research foci. I'm fascinated by the tropics, our planet's single largest climate zone, which play a key role in ice ages and the global transmission of abrupt climate signals. At the other end of the latitudinal scale, I'm also embroiled in exploring how polar ice sheets respond to warmer-than-present conditions. The East Antarctic Ice Sheet, for example, is the largest chunk of ice on Earth, with enough ice to raise sea level by > 50 m. Yet how it will behave in a greenhouse world - and implications for sea level - we don't yet know. In the mid latitudes, I seek to reconstruct the terrestrial impact of abrupt climate change, primarily in the North Atlantic and Patagonia. Once we have established when and how such events occurred, we can begin to say why the climate system behaves as it does. Glacial geology, cosmogenic nuclides, snowline reconstruction, and palaeoecology are the foundation of my research and I am lucky to call the world's most spectacular environments my laboratory. I'm always happy to hear from prospective students whose interests overlap with my own; if you are considering graduate school and serious about field-based geology, don't hesitate to get in touch.
Ice sheet stability in a warming world, East Antarctica
How will the massive East Antarctic Ice Sheet (EAIS) respond to continued warming of the climate system? Will it collapse into the ocean, raising sea level by as much as 55 m globally, or will it prove impervious to warming on the scale anticipated for the coming centuries? Perhaps the ice sheet might even grow as snowfall increases. Each of these is a fascinating and pertinent hypothesis, yet difficult to test in the absence of robust geologic data, from Antarctica itself, to show how the EAIS behaved during previous periods of warmer-than-present climate. Our goal is to provide those data.
Testing the role of CO2 in the last glacial termination, Andes
We know carbon dioxide is a greenhouse gas, but projecting the impact of anthropogenic CO2 on future climate is complicated by uncertainties surrounding climate sensitivity. To help address those uncertainties, we are comparing the geologic record of tropical temperature change to high-resolution CO2 data from the new West Antarctic ice core to assess the relationship between the two. Our focus is the last glacial-interglacial transition (or 'termination'), as this was the highest-magnitude natural global warming of the last 100,000 years. And our laboratory for this investigation is the tropics, where glaciers clinging to the highest peaks of Colombia and Peru serve as exquisite palaeothermometers taking the temperature of the tropical troposphere. After all, as the tropics go so goes the world.
Blowing Hot or Cold? Assessing the terrestrial impact of North Atlantic stadials and abrupt climate change
What drives abrupt climate change? With continued population growth, increasing pressure on natural resources, and rising CO2 concentrations, understanding the causes and effects of abrupt climate change poses one of the greatest challenges to 21st Century climatology. Thus developing our knowledge of past perturbations is key to minimising the risk of future 'climate shock'. This project, which began in 2010, utilises a geologic approach to resolve the terrestrial expression of past abrupt climate change in the North Atlantic region, which is widely held as a central player – if not the driver – of abrupt change, to help identify the mechanisms driving these potentially catastrophic phenomena. Of particular interest are Heinrich stadials 1 and 0, and the abrupt transitions associated with them.
Fire and Ice in the Central Volcanic Zone
Causative links between deglaciation and magmatism have long been hypothesised and, along divergent plate boundaries (i.e., Iceland), quantified to varying degrees. But what happens along convergent margins when large amounts of ice are suddenly removed from atop volcanoes? What is the effect of such unloading on magma chamber evolution? Quite simply, we don't know, yet the question is increasingly important as our planet warms and the glaciers and ice caps mantling active and dormant volcanoes worldwide continue to shrink. This new investigation combines geomorphology and geochemistry to explore the impact of rapid deglaciation on the internal workings of volcanic systems in the Pacific Ring of Fire.