The Scientific community has significantly underestimated the extent of global warming, a new study reveals. The previous miscalculation occurred due to sparse historical temperature data from Southern Hemisphere. In a new study, scientists analyzed satellite observations of ocean surface height changes along with ocean temperature data collected from 1970 to 2004. And then they compared results with climate models.
Sea surface height a key indicator of global warming
Comparisons revealed that oceans of the Southern Hemisphere have been absorbing more than twice as much heat as previously estimated by direct in-situ measurements. Led by Dr Paul Durack of Lawrence Livermore National Laboratory in California, scientists published the study in the journal Nature Climate Change. Ocean surface height is a key indicator of global warming. Sea levels rise with increase in temperature due to the melting of land ice.
Findings of the study suggest that previous estimates of Northern Hemisphere ocean warming are right. But it’s an entirely different story in the Southern Hemisphere. Durack and his colleagues found that ocean surface height between Northern and Southern Hemispheres represented by climate models is in line with the satellite observations that we have been using since 1993. Note that satellite observations are highly accurate.
But warming estimates in the top 700 meters of the world’s oceans simulated by climate models are not consistent with sea temperature data collected before 2004. Durack said that the inconsistency between upper ocean warming in climate models and their observations disappeared when they compared data from more recent decades with both modeled ocean surface height changes and satellite observations.
Oceans store over 90% of excess heat
Precise satellite data and a large suite of climate model simulations suggest that we previously underestimated upper ocean warming by 24% to 58%. Though some past studies have also showed that we underestimated global warming, it’s the first time scientists have quantified the extent of our miscalculations.
Findings of this study are very important because the world’s oceans store over 90% of the excess heat linked to global warming. Durack says global ocean should be observed adequately as it plays an important role in our planet’s climate.