When scientists try to determine climate change over time they look at physical objects. The rings on ancient trees or the sediment on exposed cliffs are good indicators.
But when it comes to the ocean warming, finding signs that reveal its historic temperature is much harder. Basically it comes down to ship travel, and as ship travels more around the world, so did the sophistication of their techniques improve and their frequency increased. What has resulted is a mish-mash of data taken from different parts of the world with a variety of accuracies.
Now a new study has put into question some of those findings and suggested that the oceans are actually warming much faster than previously thought.
The study by researchers at the Institute of Atmospheric Physics explains that much of the oceanic temperature data taken from the 1970s to early 1980s was flawed, captured by a deficient device known as the eXpendable BathyThermograph. Used widely by climate scientists, the researchers say that systemic bias in the device led to unusually warm readings during those decades, and thus throwing the data off.
“What my colleagues determined was that we could reduce past errors in the ocean heat content (OHC) record by correcting systematic measurement biases, filling in gaps where no information is available, and by choosing a proper comparison climate,” writes one of the coauthors John Abraham in The Guardian. “This new paper doesn’t solve all of the OHC issues, but it makes a great stride in clearing up past questions.”
The author explains that ocean warming is perhaps the greatest measurement of climate change because 90 percent of the energy coming to earth is absorbed by the ocean. In analyzing the data with a new set of eyes, researchers found that the uppermost portion of seawater down to 700 meters had increased 0.3 degrees Celsius since the 1970s.
“While that may not sound like a lot, we have to remember this is a huge amount of water and consequently it requires an enormous amount of energy,” Abraham writes.
Further analysis shows that climate models had under-predicted the ocean’s warming trend by 15 percent, which all goes to say that the ocean is getting warmer, faster than scientists previously thought.