What is your subject and specific area of study?

I study environmental science within the Department of Geography. My research interests primarily concern the functioning of terrestrial ecosystems (vegetation and soils) and how they interact with their physical environment. Understanding environmental controls on vegetation is important because all food and fibre on which humanity depends has its origin in photosynthesis and terrestrial ecosystems play a major role in the dynamics of atmospheric CO₂, the most important anthropogenic greenhouse gas. Therefore, there is tremendous interest in forecasting potential impacts of environmental change on terrestrial ecosystems and feedbacks on climate through the global carbon cycle.

The world's vegetation (including marine phytoplankton) and soils have been providing humanity with a little appreciated yet critical service – the sequestering of over 50% of anthropogenic CO₂ emissions (mainly resulting from the burning of fossil fuels and deforestation) since the beginning of the industrial revolution. Without this service the concentration of CO₂ in the atmosphere would have risen twice as fast as observed, with consequentially greater changes in the Earth's climate. Despite the obvious importance of this net uptake, it has proved difficult to attribute it to particular processes and, perhaps more importantly, predict its future behaviour. We now believe that about half of this net uptake has occurred in the oceans, and therefore the rest of this "sink" must be on land. However there is no consensus as to the process or processes that might be responsible.

Without this knowledge it is not possible to predict future atmospheric CO₂ concentrations, and hence climate, even if we knew future anthropogenic emissions.

Understanding the potential impacts of future climate change and atmospheric CO₂ concentrations on terrestrial ecosystems is also important for many other reasons, including the services ecosystems provide humans and their intrinsic value. We would like to know not only responses of processes that will determine the future status of the terrestrial CO₂ sink such as photosynthesis, respiration, and growth, but also changes in attributes such as distribution, biodiversity, and resilience. While we have a relatively good understanding of fundamental ecosystem processes for specific sites and species, major challenges remain in scaling this knowledge up in time and space to answer questions of future responses at regional and global scales.

I am trying to address these issues by building mechanistic numerical models of terrestrial ecosystem dynamics that aim to predict the distribution and attributes of global vegetation and soils from the underlying processes. These models can be used "off-line", with inputs from observations of past, and scenarios of future, climate and atmospheric CO₂ to predict ecosystem responses, and they can be coupled to global climate/biogeochemistry models to explore feedbacks through changes in land surface-atmosphere water and energy exchange and the global carbon cycle. One striking finding is that uncertainty concerning how terrestrial ecosystem physiology responds to climate change is similar to the uncertainty with respect to future economic growth and technological development for anticipating levels of atmospheric CO₂, and hence climate change, to the end of this century! Key processes are the responses of photosynthesis to CO₂ and respiration to temperature, as well as the ability of ecosystems to adapt to unfavourable climatic regimes caused by changing rainfall patterns and increasing temperatures.

By continuing to develop and test models across a wide range of scales I hope to reduce these uncertainties and produce improved predictions of the properties of future ecosystems and their interaction with atmospheric processes.

What makes Clare College such a good place to study your subject?

Clare College has 2-3 geography students in each year and one fellow, ensuring a supportive environment for the study of this diverse and exciting subject. The College and Department work closely together to plan supervision teaching and dissertation work, and give general advice on course selection and study skills. Clare is committed to providing a stimulating academic environment with students and fellows working in subjects across the full range of arts and sciences.