- Over the past quarter-century, Earth’s oceans have retained 60 percent more heat each year than scientists previously had thought per the startling study published Wednesday in the journal Nature.
- The difference represents an enormous amount of additional energy, originating from the sun and trapped by Earth’s atmosphere — the yearly amount representing more than eight times the world’s annual energy consumption.
- To prevent temperatures from rising above 2C (3.6F warming in industrial era), emissions of carbon dioxide must be reduced by 25 percent compared to what was previously estimated.
- The study is an example of how collecting long term data can have unexpected benefits.
- The researchers’ results are the first to come from a measuring technique independent from the dominant method behind existing research.
Since 1991, the world’s oceans have absorbed an amount of heat energy each year that is 150 times the energy humans produce as electricity annually, according to a new study. The strong ocean warming the researchers found suggests that Earth is more sensitive to fossil-fuel emissions than previously thought….
…Scientists know that the ocean takes up roughly 90 percent of all the excess energy produced as Earth warms, so knowing the actual amount of energy makes it possible to estimate the surface warming we can expect, said co-author Ralph Keeling, a Scripps Oceanography geophysicist and Resplandy’s former postdoctoral adviser….
…[From NY Times] Scientists normally measure ocean temperatures using thermometers, but stitching together a global temperature record requires thermometers around the globe. Global temperature records were spotty before 2007, when an international consortium began a program, known as Argo, creating an international network of ocean-temperature-measuring instruments. But a group from Scripps Institution of Oceanography had been taking careful measurements of atmospheric carbon dioxide since 1991, for unrelated reasons. Dr. Resplandy and her team used that data set for this study. Dr. Nicholson said the study was an example of how collecting data now can have unexpected benefits later….
ABSTRACT: The ocean is the main source of thermal inertia in the climate system1. During recent decades, ocean heat uptake has been quantified by using hydrographic temperature measurements and data from the Argo float program, which expanded its coverage after 20072,3. However, these estimates all use the same imperfect ocean dataset and share additional uncertainties resulting from sparse coverage, especially before 20074,5. Here we provide an independent estimate by using measurements of atmospheric oxygen (O2) and carbon dioxide (CO2)—levels of which increase as the ocean warms and releases gases—as a whole-ocean thermometer. We show that the ocean gained 1.33 ± 0.20 × 1022 joules of heat per year between 1991 and 2016, equivalent to a planetary energy imbalance of 0.83 ± 0.11 watts per square metre of Earth’s surface. We also find that the ocean-warming effect that led to the outgassing of O2 and CO2 can be isolated from the direct effects of anthropogenic emissions and CO2 sinks. Our result—which relies on high-precision O2 measurements dating back to 19916—suggests that ocean warming is at the high end of previous estimates, with implications for policy-relevant measurements of the Earth response to climate change, such as climate sensitivity to greenhouse gases7 and the thermal component of sea-level rise8.
Resplandy, Keeling, Eddebbar, Brooks et al. Quantification of ocean heat uptake from changes in atmospheric O2 and CO2 composition. Nature Nov 2018.