Han Dolman
Royal NIOZ, Texel, Netherlands and Department of Earth Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands, Royal NIOZ, Texel, Netherlands and Department of Earth Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands, Vrije Universiteit
Author ProfileValentin Aich
Global Climate Observing System, World Meteorological Organization, Geneva, Switzerland, Global Climate Observing System, World Meteorological Organization, Geneva, Switzerland, World Meteorological Organization
Author ProfileAbstract
Fossil fuel combustion, land use change and other human activities have
increased the atmospheric carbon dioxide (CO2) abundance by about 50%
since the beginning of the industrial age. The atmospheric CO2 growth
rates would have been much larger if natural sinks in the land biosphere
and ocean had not removed over half of this anthropogenic CO2. As these
CO2 emissions grew, uptake by the ocean increased in response to
increases in atmospheric CO2 partial pressure (pCO2). On land, gross
primary production (GPP) also increased, but the emerging dynamics of
other key aspects of the land carbon cycle varied regionally. Over the
past three decades, CO2 uptake by intact tropical humid forests has
declined, but these changes are offset by increased uptake across mid-
and high-latitudes. While there have been substantial improvements in
our ability to study the carbon cycle, measurement and modeling gaps
still limit our understanding of the processes driving its evolution.
Continued ship-based observations combined with expanded deployments of
autonomous platforms are needed to quantify ocean-atmosphere fluxes and
interior ocean carbon storage on policy-relevant spatial and temporal
scales. There is also an urgent need for more comprehensive measurements
of stocks, fluxes and atmospheric CO2 in humid tropical forests and
across the Arctic and boreal regions, which are experiencing rapid
change. Here, we review the current state of knowledge of the
atmosphere, ocean, and land carbon cycles and their interactions and
identify emerging measurement and modeling capabilities and gaps.