New Record Ocean Temperatures and Related Climate Indicators in 2023
More than 90% of the Earth’s energy imbalance under climate change is absorbed by the ocean, making ocean heat content a critical index for tracking climate change. However, sampling of ocean temperatures remains sparse, requiring various methods for infilling data gaps and correcting for biases in observations. This work uses two data products to estimate key indicators of the ocean state in 2023, including an analysis of various salinity-based indices.
This work tracks the progression of global warming in fields that exhibit a high signal-to-noise ratio as compared to surface temperature. The findings reveal continued increases in Earth’s ocean heat uptake, upper ocean stratification, and salinity spatial contrasts, underscoring the ongoing effects of climate change on Earth’s energy and water cycles.
The global physical and biogeochemical environment has been substantially altered in response to increased atmospheric greenhouse gases from human activities. In 2023, the sea surface temperature (SST) and upper 2000 m ocean heat content (OHC) reached record highs. The 0–2000 m OHC in 2023 exceeded that of 2022 by 15 ± 10 ZJ (1 Zetta Joules = 1021 Joules) (updated IAP/CAS data); 9 ± 5 ZJ (NCEI/NOAA data). The Tropical Atlantic Ocean, the Mediterranean Sea, and southern oceans recorded their highest OHC observed since the 1950s. Associated with the onset of a strong El Niño, the global SST reached its record high in 2023 with an annual mean of ~0.23 °C higher than 2022 and an astounding > 0.3 °C above 2022 values for the second half of 2023. The density stratification and spatial temperature inhomogeneity indexes reached their highest values in 2023.