Increases in atmospheric CO2 and CH4 result from a combination of forcing
from anthropogenic emissions and Earth System feedbacks that reduce or amplify
the effects of those emissions on atmospheric concentrations. Despite decades
of research carbon-climate feedbacks remain poorly quantified. The impact of
these uncertainties on future climate are of increasing concern, especially in
the wake of recent climate negotiations. Emissions, long concentrated in the
developed world, are now shifting to developing countries, where the emissions
inventories have larger uncertainties. The fraction of anthropogenic CO2
remaining in the atmosphere has remained remarkably constant over the last 50
years. Will this change in the future as the climate evolves? Concentrations of
CH4, the 2nd most important greenhouse gas, which had apparently stabilized,
have recently resumed their increase, but the exact cause for this is unknown.
While greenhouse gases affect the global atmosphere, their sources and sinks
are remarkably heterogeneous in time and space, and traditional in situ
observing systems do not provide the coverage and resolution to attribute the
changes to these greenhouse gases to specific sources or sinks. In the past few
years, space-based technologies have shown promise for monitoring carbon stocks
and fluxes. Advanced versions of these capabilities could transform our
understanding and provide the data needed to quantify carbon-climate feedbacks.
A new observing system that allows resolving global high resolution fluxes will
capture variations on time and space scales that allow the attribution of these
fluxes to underlying mechanisms.