Looking back and looking forwards: Historical and future trends in sea surface temperature (SST) in the Indo-Pacific region from 1982 to 2100

• A warming trends detected for all sea surface temperature (SST) variables.
• In the Coral Triangle a warming trend with a rate of 0.013 °C year−1, 0.017 °C year−1, and 0.019 °C year−1 was detected over 29 years for MaxSST, MeanSST and MinSST, respectively.
• In the SCS, the warming rate was 0.011 °C year−1, (MaxSST), 0.012 °C year−1 (MeanSST) and 0.015 °C year−1 (MinSST) over 29 years.
• The CMIP5 RCP2.6 forecast suggested a future warming rate to 2100 of 0.004 °C year−1 for both areas, and for all three SST variables.

The ocean warming trend is a well-known global phenomenon. As early as 2001, and then reiterated in 2007, the Intergovernmental Panel on Climate Change (IPCC) reported that the global average sea surface temperature (SST) will increase by about 0.2 °C per decade. To date, however, only a limited number of studies have been published reporting the spatio-temporal trends in SST in the Indo-Pacific region, one the richest marine ecosystems on Earth. In this research, the monthly 1° spatial resolution NOAA Optimum Interpolation (OI) sea surface temperature (SST) V2 dataset (OISSTv2) derived from measurements made by the Advanced Very High Resolution Radiometer (AVHRR) and in situ measurements, were used to examine the spatio-temporal trends in SST in the region. The multi-model mean SST from the Representative Concentration Pathways (RCP2.6) mitigation scenario of the Coupled Model Intercomparison Project Phase 5 (CMIP5) was also used to forecast future SST from 2020 to 2100, decadally. Three variables from the OISSTv2, namely maximum (MaxSST), mean (MeanSST) and minimum (MinSST) monthly mean SST, were regressed against time measured in months from 1982 to 2010 using linear regression. Results revealed warming trends detected for all three SST variables. In the Coral Triangle a warming trend with a rate of 0.013 °C year−1, 0.017 °C year−1, and 0.019 °C year−1 was detected over 29 years for MaxSST, MeanSST and MinSST, respectively. In the SCS, the warming rate was 0.011 °C year−1, (MaxSST), 0.012 °C year−1 (MeanSST) and 0.015 °C year−1 (MinSST) over 29 years. The CMIP5 RCP2.6 forecast suggested a future warming rate to 2100 of 0.004 °C year−1 for both areas, and for all three SST variables. The warming trends reported in this study provide useful insights for improved marine-related management.