Environment

Flaw in ocean temperature models suggests climate change could be worse than predicted

Flaw in ocean temperature mode...
Our ocean's temperature may have been more stable over the past 100 million years than we thought
Our ocean's temperature may have been more stable over the past 100 million years than we thought
View 1 Image
Our ocean's temperature may have been more stable over the past 100 million years than we thought
1/1
Our ocean's temperature may have been more stable over the past 100 million years than we thought

A newly published study conducted by a collaborative team of French and Swiss researchers is suggesting a flaw in the way past ocean temperatures have been estimated. This discovery claims that oceans may have been much cooler over the past 100 million years than records suggest, meaning that the recent spike in ocean temperatures might be more significant and alarming than we thought.

"Oceans cover 70 percent of our planet," explains Anders Meibom, one of the authors of the study from the University of Lausanne. "They play a key role in the earth's climate. Knowing the extent to which their temperatures have varied over geological time is crucial if we are to gain a fuller understanding of how they behave and to predict the consequences of current climate change more accurately."

Over the last few decades, scientists have developed increasingly sophisticated methods to track our ocean's temperature. From a global network of monitoring stations called Argo floats to newer satellite based technology, every day offers a clearer picture of how climate change is warming our oceans.

In order to estimate how ocean temperatures have varied over millions of years, scientists traditionally measure the presence of an oxygen isotope (oxygen-18) found in tiny marine fossils called foraminifera. It was generally thought that the oxygen-18 content found in the calcareous shells was fixed and unchanging over time. These measurements suggested that our global ocean temperature was around 15° Celsius (27° F) warmer 100 million years ago than today.

The new study claims this measurement technique is flawed and shows that the level of oxygen-18 present in foraminifera can in fact change over time. The scientists demonstrated this by exposing the fossils to high temperatures in artificial seawater containing oxygen-18, and through chemical analysis found that it was in fact able to absorb the isotope.

"What appeared to be perfectly preserved fossils are in fact not," says Sylvain Bernard, the study's lead author. "This means that the paleotemperature estimates made up to now are incorrect."

The scientists claim the previous 15-degree temperature shift identified in the fossil record can be explained by a process called re-equilibration. This refers to rises in temperature of up to 30° Celsius (54° F) that occur during sedimentation, causing the foraminifera re-equilibrate with the surrounding water.

"To revisit the ocean's paleotemperatures now, we need to carefully quantify this re-equilibration, which has been overlooked for too long," says Meibom. "For that, we have to work on other types of marine organisms so that we clearly understand what took place in the sediment over geological time."

After running new computer simulations, the team suggest that current paleotemperature estimations have been overstated and ocean temperatures over the past 100 million years may have actually been much more stable. The striking implication of the study is our currently rising ocean temperatures are much more anomalous that previously thought. If global ocean temperatures were in fact relatively stable over the past 100 million years then our current, more accurate measurements are exponentially more disturbing, suggesting a nearly 1 degree rise over the past century.

The new research was published in the journal Nature Communications.

Source: École Polytechnique Fédérale de Lausanne

10 comments
Robert in Vancouver
I have lived a few yards from the Pacific Ocean for 49 years and see the tides marks on piers and rocks have not changed at all. If there was global warming, those tide marks would get higher. But they have stayed the same for 49 years.
aki009
Yes. And it is entirely plausible that in a parallel universe pigs could have evolved with wings so that they could fly. Are these the same computer simulations that 15 years ago predicted that by now I would be going to Antarctica for beach vacations and the North Pole for fishing?
piperTom
Article refers to " 30° Celsius (54° F) "; it's actually 86° F . And that's just a hint at the mistakes in this multi-decadal "settled science". We're supposed to panic and change the way we live, because some scientists can get grant money from alarmism.
Jose Gros
'Science' published in Nov 2015 an specialized issue: 'Sea changes', it points to raises between 10 m and 60 + meters in Sea Level occurring thousand centuries ago, with the same CO2 levels of today, 400 ppm, and a similar temperature raise, 2º C above pre-industrial levels. CO2 and other greenhouse effect gases are increasing, it could take years to slow and stop the increase, more to revert it, all feed-back loops increase and speed-up temperature increases, with all its consequences. The Paris meeting set a goal not to surpass of 1.5º C above pre-industrial level (PIL) mean, the Marrakech meeting raised the not to trespass limit to 1.7º C above PIL, but in these two years of high Solar energy output, 2016 and 2017, with a peak in Solar cycle, (that came late from expected time, solar peaks increase energy radiated in 0.01%, peaks go along with more Sun Spots, next peak will come around 2029), the limits of 1.5º C and 1.7º C were actually surpassed. If I lived in the shore, I'll check the local forecasts in 'Sea Level raise maps', or you risk being forced to sing: '5 feet high and rising', along with Johnny Cash.
chase
@ robo - and I've lived along the shoreline my whole life and have seen dramatic increase in the tide tables in just the past 15-20 years. Rising tides flooding breaching sea walls to the extent of flooding inland areas. Breaching to the extent that 3 South Florida counties have gotten together to try and figure out a resolve. Which there doesn't seem one is possible as of yet. Hence they have decided to forgo repairs or raising current sea walls. There are entire neighborhoods in some of the more "prestigious" areas in town being flooded out every high tide. Especially during winter months. They raised the bridges last year just getting on and off some areas due to the high tide waters. New development in these areas, which there's plenty, are not telling people that buy homes, or condos about the flooding. The residents nice expensive cars are definitely sercuming to the rath of salt water on metal. Lol... Needless to say, new buyers are rather ticked off not having been told... I can provide plenty of pics and video of these tidal changes as was predicted more than a decade ago.
Douglas Bennett Rogers
Desert irrigation represents about five times the greenhouse effect of industrial CO2.
RobertEhresman
There is no question that climate models are flawed. Total failure to predict actual climate is the clue.
aksdad
Yes, those lovely climate models that are famously inaccurate. As IPCC AR5 helpfully notes "Because knowledge of the climate system’s past and current states is generally imperfect, as are the models that utilize this knowledge to produce a climate prediction, and because the climate system is inherently nonlinear and chaotic, predictability of the climate system is inherently limited". And that's all you need to know to ignore any prediction based on climate models. @chase, you haven't seen any such thing. The longest data set for south Florida is in Naples and the trend since the 1960's averages +2.7 mm per year with no noticeable difference in rate since the 1980's. That means in the past 20 years sea level has risen 54 mm or about 2.1 inches. All of Florida is close to sea level and given the right circumstances (storms, flood tides, hurricanes) seas will inundate the lowest-lying areas. A paltry 2 inches is nothing to get excited about, though. See NOAA Sea Level Trends website for a tide gauge near you: https://tidesandcurrents.noaa.gov/sltrends/sltrends.html
ljaques
Aha, -there's- the other shoe. I just read the story about the old dual eruptions from Yellowstone and wondered where the missing "OMIGODWEREALLGONNADIE" was. We found it! Here are some historical sea levels which might amuse those of us who don't buy the current hysteria: https://en.wikipedia.org/wiki/Past_sea_level . As far as IPCC and their climate models, they ack that they're flawed and have continued to add dozens upon dozens of -new- data streams to it ever since they released the first report. Every new release shows different levels of rise, and they haven't gotten it right yet. They were still predicting temperature rises while the temps forgot to rise for over a decade. Oops! The bottom line is that we need to keep all the governments out of Global Warming/Climate Change/Tipping Point and let the greenies do whatever they like to save the world on their own. Now that everyone in the world is aware of the potential to live a life with a lighter footprint, the rest of us will just continue to scale back from the wasteful old days while old tech is retired and replaced with state-of-the-art devices which don't pollute. G'day!
Johannes
@piperTom - you really need to get some basic science knowledge under your belt before making stupid statements like that. A change in temperature of 30C is the same as a change in temperature of 54F. Yes, on an absolute scale 30C is 86F, but they don't start at the same point because 0C is 32F.