Heat stored in the Earth system 1960–2020: where does the energy go?

The Earth climate system is out of energy balance, and heat has accumulated continuously over the past decades, warming the ocean, the land, the cryosphere, and the atmosphere. According to the Sixth Assessment Report by Working Group I of the Intergovernmental Panel on Climate Change, this planetary warming over multiple decades is human-driven and results in unprecedented and committed changes to the Earth system, with adverse impacts for ecosystems and human systems. The Earth heat inventory provides a measure of the Earth energy imbalance (EEI) and allows for quantifying how much heat has accumulated in the Earth system, as well as where the heat is stored. Here we show that the Earth system has continued to accumulate heat, with 381±61 ZJ accumulated from 1971 to 2020. This is equivalent to a heating rate (i.e., the EEI) of 0.48±0.1 W m−2. The majority, about 89 %, of this heat is stored in the ocean, followed by about 6 % on land, 1 % in the atmosphere, and about 4 % available for melting the cryosphere. Over the most recent period (2006–2020), the EEI amounts to 0.76±0.2 W m−2. The Earth energy imbalance is the most fundamental global climate indicator that the scientific community and the public can use as the measure of how well the world is doing in the task of bringing anthropogenic climate change under control. Moreover, this indicator is highly complementary to other established ones like global mean surface temperature as it represents a robust measure of the rate of climate change and its future commitment. We call for an implementation of the Earth energy imbalance into the Paris Agreement's Global Stocktake based on best available science. The Earth heat inventory in this study, updated from von Schuckmann et al. (2020), is underpinned by worldwide multidisciplinary collaboration and demonstrates the critical importance of concerted international efforts for climate change monitoring and community-based recommendations and we also call for urgently needed actions for enabling continuity, archiving, rescuing, and calibrating efforts to assure improved and long-term monitoring capacity of the global climate observing system. The data for the Earth heat inventory are publicly available, and more details are provided in Table 4

Measuring global ocean heat content to estimate the earth energy imbalance

The energy radiated by the Earth toward space does not compensate the incoming radiation from the Sun leading to a small positive energy imbalance at the top of the atmosphere (0.4–1 Wm–2). This imbalance is coined Earth’s Energy Imbalance (EEI). It is mostly caused by anthropogenic greenhouse gas emissions and is driving the current warming of the planet. Precise monitoring of EEI is critical to assess the current status of climate change and the future evolution of climate. But the monitoring of EEI is challenging as EEI is two orders of magnitude smaller than the radiation fluxes in and out of the Earth system. Over 93% of the excess energy that is gained by the Earth in response to the positive EEI accumulates into the ocean in the form of heat. This accumulation of heat can be tracked with the ocean observing system such that today, the monitoring of Ocean Heat Content (OHC) and its long-term change provide the most efficient approach to estimate EEI. In this community paper we review the current four state-of-the-art methods to estimate global OHC changes and evaluate their relevance to derive EEI estimates on different time scales. These four methods make use of: (1) direct observations of in situ temperature; (2) satellite-based measurements of the ocean surface net heat fluxes; (3) satellite-based estimates of the thermal expansion of the ocean and (4) ocean reanalyses that assimilate observations from both satellite and in situ instruments. For each method we review the potential and the uncertainty of the method to estimate global OHC changes. We also analyze gaps in the current capability of each method and identify ways of progress for the future to fulfill the requirements of EEI monitoring. Achieving the observation of EEI with sufficient accuracy will depend on merging the remote sensing techniques with in situ measurements of key variables as an integral part of the Ocean Observing System

Large-scale ocean circulation, dynamics, and air-sea exchanges : Argo observations of the mean and time- varying ocean

The large-scale ocean circulation, dynamics, and air-sea exchanges are investigated, based on observational datasets including Argo and satellite altimetry, and viewed in the framework of modern theoretical ideas. Initially, the wind-driven interannual variability of the subtropical North Pacific is described. Using the extensive Argo dataset, it is seen that the North Pacific gyre varies in the strength of its interior circulation and in its spatial orientation, on interannual timescales. Also, satellite altimetry shows variations in sea surface height that are consistent with Argo steric height changes, and enabled a temporal extension of the 2004-2011 Argo study back to 1993. The next part of the thesis is focused on annual steric variability, including diabatic changes in the surface layer due to air-sea buoyancy fluxes and adiabatic changes due to wind-forced advection, which are dominant in the subsurface ocean. The annual signal in subsurface (200-2000 db) steric height zonally averaged over a season shows good agreement with the wind-forced vertical advection contribution, both in the global ocean and in different basins. This study, the first on global scale, also shows that the annual vertical advection extends deep into the water column. Next, the global pattern of climatological monthly heat and freshwater fluxes at the ocean surface is estimated using Argo temperature and salinity profile data for the period 2004 to 2013. The air-sea flux estimates from Argo are described in global maps and basin-wide integrals, in comparison to atmospheric reanalysis data and to air-sea flux products based on observations. This ocean-based estimate of surface fluxes is consistent with property variations in the subsurface ocean and indicates greater amplitude for the climatological monthly heat flux values in the subtropics compared to other products. Similarly, the combination of Argo freshwater flux and reanalysis evaporation, suggests greater amplitude for climatological monthly precipitation in the tropics. Finally, this thesis describes the mean field of the North Pacific subtropical gyre using Argo T/S and trajectory data. The gyre is deeper than 1975 db and than the densest ventilated isopycnal, and it is deepest in the northwest subtropics. In the east, its axis tilts northeast with increasing pressur

Large-scale ocean circulation, dynamics, and air-sea exchanges : Argo observations of the mean and time- varying ocean

The large-scale ocean circulation, dynamics, and air-sea exchanges are investigated, based on observational datasets including Argo and satellite altimetry, and viewed in the framework of modern theoretical ideas. Initially, the wind-driven interannual variability of the subtropical North Pacific is described. Using the extensive Argo dataset, it is seen that the North Pacific gyre varies in the strength of its interior circulation and in its spatial orientation, on interannual timescales. Also, satellite altimetry shows variations in sea surface height that are consistent with Argo steric height changes, and enabled a temporal extension of the 2004-2011 Argo study back to 1993. The next part of the thesis is focused on annual steric variability, including diabatic changes in the surface layer due to air-sea buoyancy fluxes and adiabatic changes due to wind-forced advection, which are dominant in the subsurface ocean. The annual signal in subsurface (200-2000 db) steric height zonally averaged over a season shows good agreement with the wind-forced vertical advection contribution, both in the global ocean and in different basins. This study, the first on global scale, also shows that the annual vertical advection extends deep into the water column. Next, the global pattern of climatological monthly heat and freshwater fluxes at the ocean surface is estimated using Argo temperature and salinity profile data for the period 2004 to 2013. The air-sea flux estimates from Argo are described in global maps and basin-wide integrals, in comparison to atmospheric reanalysis data and to air-sea flux products based on observations. This ocean-based estimate of surface fluxes is consistent with property variations in the subsurface ocean and indicates greater amplitude for the climatological monthly heat flux values in the subtropics compared to other products. Similarly, the combination of Argo freshwater flux and reanalysis evaporation, suggests greater amplitude for climatological monthly precipitation in the tropics. Finally, this thesis describes the mean field of the North Pacific subtropical gyre using Argo T/S and trajectory data. The gyre is deeper than 1975 db and than the densest ventilated isopycnal, and it is deepest in the northwest subtropics. In the east, its axis tilts northeast with increasing pressur

argovis/demo_notebooks: 0.0.1

<p>Argovis is a data distribution service for Earth system data that enables precision search and rapid download of many in-situ, satellite, and gridded reanalysis data products in the physical and biogeochemical oceanography space.</p> <p>This repository contains a collection of jupyter notebooks intended for users of Argovis' API to self-study and learn how to effectively use this service in Python.</p&gt

argovis/edu_notebooks: 0.0.3

<p>Argovis is a data distribution service for Earth system data that enables precision search and rapid download of many in-situ, satellite, and gridded reanalysis data products in the physical and biogeochemical oceanography space.</p> <p>This repository contains a collection of jupyter notebooks that use Argovis and are intended for use in broader educational activities, like university labs and classes.</p&gt

argovis/db-schema: 0.0.1

<p>Argovis is a data distribution service for Earth system data that enables precision search and rapid download of many in-situ, satellite, and gridded reanalysis data products in the physical and biogeochemical oceanography space.</p> <p>This repository contains the semi-consistent point, grid and timeseries schema rules enforced for all of Argovis' indexed datasets.</p&gt