Elevated Atmospheric CO₂, Plants and the Arctic

Arctic soils are a repository for ⅓ of the world's soil carbon. In the future, will increasing atmospheric CO₂ alter the relationship between plants and soil, affecting this carbon store?

Atmospheric CO₂ concentrations are rising due to human activity. By 2050 we expect the concentrations to be as high as 600 ppm compared with present day levels of ~390 ppm. In this study we look at how elevated concentrations of CO₂ will effect a heath plant community in Abisko in the Swedish sub-arctic.

To achieve this, nearly 20 years ago (1993) we installed an experimental system that simulates the CO₂ concentrations of the year 2050. This involved outdoor chambers where we can look at how plants and ecological processes may respond to future CO₂ concentrations.

It is also thought that the Arctic will respond earliest to climate change. This region already holds ⅓ of the world's stored soil carbon. Key research questions we address are:

  • Does the Arctic have the capacity to store additional carbon released by human activity?
  • How will the allocation of C between above - and below-ground sinks respond to elevated CO₂?
  • Will this area retain its already enormous carbon storage, or will this be released into the atmosphere contributing further to global warming?
Key parts of this system are examined in detail by our research. We look at the activity of plants and micro-organisms, paying particular attention to soil processes to determine how ecosystems will eventually respond to future elevated levels of CO₂.

Our experiments measure all flows of carbon associated with this plant community and the soil that underlies it. This is known as a 'carbon budget'. We look at the inputs and outputs of carbon by evaluating the amounts of carbon 'spent' and 'saved' by soil organisms, and plants themselves. We will measure the amounts of carbon used by soil microbes and quantities stored in the soil, comparing these with the carbon captured by plants from CO₂ during photosynthesis. Each of these processes will be altered in the future by climate change impacts. Predicted rising levels of CO₂ in the atmosphere are a part of this, so the findings of our research enable people to understand the problem and be better prepared for changes in the future.

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