Quantitative knowledge about the impacts and risks of climate variability and change as they affect terrestrial ecosystems (natural, semi-natural and managed, including forestry and agriculture), their function, biodiversity, and interactions with climate.

Climate Led by Professor Colin Prentice

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Summary

My objective is to develop and apply robust, quantitative knowledge about the impacts and risks of climate variability and change as they affect terrestrial ecosystems (natural, semi-natural and managed, including forestry and agriculture), their function, biodiversity, and interactions with climate. The ‘AXA Program in Biosphere and Climate Impacts’ is adopting an integrative approach, combining theory, diverse biological and geophysical observations, and experimental findings from ecophysiology and plant science. We are exploiting recent advances in data availability (plant functional traits, and geospatial measurements from remote sensing and other sources), and new understanding of carbon, water and nutrient cycling, to create well-founded methods to assess the consequences of climate variability and change for plants, ecosystems and land use. The methods will be applied with contemporary climate data and state-of-the-art climate projections for decade to century time scales, to evaluate worldwide consequences for land ecosystems, risks and opportunities for forestry, arable crops and bioenergy production, changes in carbon, water and nutrient cycles, sources and sinks of trace gases and aerosols, and feedbacks to atmospheric composition and climate.

The challenge

The need for reliable information, based on fundamental research on the consequences of climate change, is already great and is set only to increase. The nature of climate change is such that we are currently (mainly) anticipating it, whereas in 20-30 years‘ time we will be experiencing it, and evaluating its consequences – and necessary adaptations to avert the worst of these – is an urgent, practical matter. Yet only a very few universities or research institutions worldwide are actively promoting the necessary research, which crosses the boundaries of physical climate science and biological science.

Climate modelling is essential as a guide to the range of plausible climate futures, and to assess the consequences of human interventions. These include land-use changes and proposed geo-engineering schemes, as well as greenhouse gas and aerosol emissions. Land biosphere/carbon cycle modelling is also essential for the prediction of consequences and risks of climate variability and climate change for biodiversity, ecosystems and human activities. However, there remains an alarmingly large uncertainty in the predictions made by current state-of-the-art land biosphere and carbon cycle models, and there is an urgent need for quantitative understanding and prediction of how ecosystems and primary production (including plant growth, forest and crop yields) will respond to climate variability and change.

The interactions of climate and the biosphere, moreover, do not end with impacts. There are feedback loops as well, but the extent to which feedback will affect systems is still not adequately understood, and most of the uncertainty in the feedback systems stems from the terrestrial biosphere components of the models.

Hydrology is by no means independent of biology. Vegetation and land use have well-documented impacts on the partitioning of precipitation between evapotranspiration and runoff, which most conventional hydrological models ignore. What is needed now is to combine observations and modelling from different fields, in this case, ecophysiology and hydrology. Most land biosphere models have become unmanageably complex, with too many (poorly constrained) parameters. But fortunately, there is now enough information to simplify these land biosphere models. The challenge now is to combine the existing data from older models, with the latest research to develop a ‘next generation’ model that is simpler and provides information on the impacts of climate variability and change on the land surface.

Insights

My research program focuses on the implications of climate variability and change over the next 25 - 100 years for the terrestrial biosphere, including the use of land for food, fibre and energy production, recognizing the multiplicity of drivers of land-use change. This programme is an opportunity for substantial progress in integrative and collaborative research, bringing in existing knowledge and external expertise from across these domains.

At the core of the program is the development of ‘next generation’ process-based models to describe and forecast the responses of plants and ecosystems to atmospheric composition and climate to describe and forecast changes in crop yields and the suitability of different crops and agricultural systems. This research is already beginning to move the biosphere modelling enterprise ahead of current global vegetation models and forestry and crop models, which are for the most part based on the state of knowledge circa 1990.

The future

It is hoped that by establishing this next-generation Dynamic Global Vegetation Model, this research can lead to:

  • Explicit, generally simple re-formulations of all of the key processes at plant and ecosystem levels, based on a combination of information from experiments and data syntheses with theory based on the requirements of biophysical co-ordination and evolutionary optimization.
  • A transparent model structure in which parameters are (a) kept to a minimum, and (b) constrained by observations both from the bottom up (plant and leaf level measurements) and the top down (ecosystem, regional and global measurements).
  • A next-generation model that includes the above features in a well-tested computational environment for the worldwide assessment of environmental change impacts on ecosystems.

Funders and sponsors

My work is funded through:

  • AXA
  • Imperial College London: support positions and PhD studentships
  • The National Environmental Research Council (NERC)
  • The EU FP7 EMBRACE  project (Earth system Model Bias Reduction and assessing Abrupt Climate change) (led by Dr Colin Jones, SMHI)
  • Macquarie University, Australia: PhD studentships
  • The Australian Research Council: project “Next-generation vegetation model based on functional traits” (with Dr Ian Wright, Macquarie University)