Challenges in scaling up greenhouse gas fluxes: experience from the UK
Greenhouse Gas Emissions and Feedbacks Programme
The role of greenhouse gases (GHGs) in global climate change is now well
recognised and there is a clear need to measure emissions and verify the
efficacy of mitigation measures. To this end, reliable estimates are
needed of the GHG balance at national scale and over long time periods,
but these estimates are difficult to make accurately.
Because measurement techniques are generally restricted to relatively
small spatial and temporal scales, there is a fundamental problem in
translating these into long-term estimates on a regional scale.
The key challenge lies in spatial and temporal upscaling of short-term,
point observations to estimate large-scale annual totals, and
quantifying the uncertainty associated with this upscaling.
Here, we review some approaches to this problem, and synthesise the work
in the recent UK Greenhouse Gas Emissions and Feedbacks Programme, which
was designed to identify and address these
Approaches to the scaling problem
instrumentation developments which mean that near-continuous data sets
can be produced with larger spatial coverage;
geostatistical methods which address the problem of extrapolating to
larger domains, using spatial information in the data;
more rigorous statistical methods which characterise the uncertainty in
extrapolating to longer time scales;
analytical approaches to estimating model aggregation error; enhanced
estimates of C flux measurement error;
and novel uses of remote sensing data to calibrate process models for
generating probabilistic regional C flux estimates.