Reconstruction of the history of anthropogenic CO2 concentrations in the ocean
By Samar Khatiwala, F. Primeau, Todd H. Hall. Nature, 2009
617 citations recorded by the source corpus.
The release of fossil fuel CO2 to the atmosphere by human activity has been implicated as the predominant cause of recent global climate change. The ocean plays a crucial role in mitigating the effects of this perturbation to the climate system, sequestering 20 to 35 per cent of anthropogenic CO2 emissions. Although much progress has been made in recent years in understanding and quantifying this sink, considerable uncertainties remain as to the distribution of anthropogenic CO2 in the ocean, its rate of uptake over the industrial era, and the relative roles of the ocean and terrestrial biosphere in anthropogenic CO2 sequestration. Here we address these questions by presenting an observationally based reconstruction of the spatially resolved, time-dependent history of anthropogenic carbon in the ocean over the industrial era. Our approach is based on the recognition that the transport of tracers in the ocean can be described by a Green’s function, which we estimate from tracer data using a maximum entropy deconvolution technique. Our results indicate that ocean uptake of anthropogenic CO2 has increased sharply since the 1950s, with a small decline in the rate of increase in the last few decades. We estimate the inventory and uptake rate of anthropogenic CO2 in 2008 at 140 ± 25 Pg C and 2.3 ± 0.6 Pg C yr-1, respectively. We find that the Southern Ocean is the primary conduit by which this CO2 enters the ocean (contributing over 40 per cent of the anthropogenic CO2 inventory in the ocean in 2008). Our results also suggest that the terrestrial biosphere was a source of CO2 until the 1940s, subsequently turning into a sink. Taken over the entire industrial period, and accounting for uncertainties, we estimate that the terrestrial biosphere has been anywhere from neutral to a net source of CO2, contributing up to half as much CO2 as has been taken up by the ocean over the same period.
Subfields: Global and Planetary Change, Oceanography
View Paper: https://www.semanticscholar.org/paper/5b605e3f80e020753244112e714188f634a8503f
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Citations in the corpus
- Satellite Salinity Observing System: Recent Discoveries and the Way Forward (2019, background): “Since the industrial revolution, the oceans have absorbed about 40–50% of the anthropogenic carbon dioxide (CO2) emissions to the atmosphere (Sabine et al., 2004; Khatiwala et al., 2009), mitigating the impact of global warming.”
- Patterns, processes and vulnerability of Southern Ocean benthos: a decadal leap in knowledge and understanding (2013, background): “Ecosystems in the Southern Ocean are projected to be affected more severely by ocean acidification than elsewhere due to the higher solubility of CO2 at lower temperatures and regular upwelling of CO2-enriched waters (Fabry et al. 2009); the oceans south of 40 S take up about 40 % of anthropogenic C”
- State of the climate in 2010 (2011, methodology): “Figure 3.33 shows a compilation of these recent marginal sea estimates together with the 2008 open ocean Cant distributions estimated using the approach of Khatiwala et al. (2009).”
- Temperature dependency of metabolic rates in the upper ocean: A positive feedback to global climate change? (2018, background): “The ocean sequesters a third to a quarter of the carbon released by human activities each year (Sabine et al., 2004; Khatiwala et al., 2009) and the transfer of this carbon to the interior of the ocean depends partly on the functioning of the biological pump (Fig.”