Quantifying ocean heat and anthropogenic carbon uptake

Quantifying ocean heat and anthropogenic carbon uptake

The ocean is one of the primary natural factors mitigating the impact of fossil fuel carbon emissions on climate. It is a “sink” for both over 30% of those emissions and 90% of the resulting radiative forcing due to the “extra’’ CO2 in the atmosphere. It may also be responsible for the recent “hiatus” in global warming which has been jumped on by climate sceptics. Understanding where, how much and by what processes this carbon and heat are absorbed by the ocean is thus a critically important problem in ocean and climate science. Moreover, the ocean is not only a sink of anthropogenic CO2 and heat  but, on time scales longer than a few decades, can also be a source as these tracers are transported via ocean circulation from the surface to the interior and eventually back to the surface where they can impact the atmosphere and hence climate. The goal of the project is to investigate this “cycling” of heat and CO2 between the ocean and atmosphere using the mathematical machinery of Green functions, which describe the advective-diffusive transport of tracers in any geophysical fluid such as the ocean and atmosphere. Green functions, both simulated in models and estimated from data, will be used to rigorously quantify ventilation, ocean interior pathways and subsequent re-emergence of water “tagged” with climatically important tracers such as heat and anthropogenic CO2.