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Home / Science / Research showing steeper increases in ocean heat is not exactly new. So what’s up with all those headlines?

Research showing steeper increases in ocean heat is not exactly new. So what’s up with all those headlines?



There is good evidence that the oceans are overheating faster than thought. Now, the scientists have joined the pieces of the puzzle.

  The trend of oceanic heat is shown for the period 1993 to 2015. The yellow, orange and red tones show the positions where ocean heat has increased. (Source: Cheng, Lijing and NCAR) Last modified on 10 May 2017.

The trend in the amount of heat in the oceans is shown for the period from 1993 to 2015. The yellow, orange and red tones show the locations where the Oceanic heat is increased (Source: Lijing Cheng and NCAR) Extract from https://climatedataguide.ucar.edu/climate-data/ocean-temperature-analysis-and-heat-content-estimate-institute-atmospheric-physics.) [19659004] I know this morning, while I'm drinking my coffee and reading the news headlines, I see this in the New York Times: "Ocean warming is accelerating faster than thought, new research results."

The story was about a new article published Thursday in the journal Science entitled "How fast do the oceans warm up?"

This is a big problem, because global warming caused by humans does not only affect the Earth's surface, in fact over 90% of global warming heat is absorbed by the oceans and this has helped to prevent a lot of temperature rises. more accentuated on earth [19659005] But all that heat that enters the oceans is not actually a benign phenomenon. By expanding ocean waters, it contributes to sea level rise. Heat can also make storms more destructive and is putting tremendous stress on ocean ecosystems – which are heavily dependent on food.

And in the long run, what happens in the oceans does not remain in the oceans. The heat eventually comes out of the water to contribute to the heating of atmospheric temperatures all over the world.

So knowing exactly how much heat is going is very important. With this in mind, I checked out more stories about the new Science article, and I saw that many of them had similar headlines like the N. Y. Times.

More information on the scientific document in a minute. But first, I must say that I realized I had already seen very similar titles. Last October, for example, I saw in Scientific American: "The Oceans are overheating more than expected". According to the story, a "new study published yesterday in the journal Nature concluded that the global oceans could be absorbed by 60% more heat from the years" compared to previous estimates. " [19659005] And almost two years ago, the Washington Post published this title: "The world's oceans store incredible amounts of heat – and it's even more than we thought." This was based on a study published in the journal Science Advances. In a press release about this, the co-author of the National Center for Atmospheric Research study Keven Trenberth said that "the planet is overheating much more than we thought."

Hmmm. Two years ago we already knew that the planet was warming up much more than we thought. So what happens to today's titles, which seem to suggest we did not know?

For quite some time, scientists actually had good reason to believe that the oceans absorbed more heat than global warming than was estimated in an important 2014 report by the intergovernmental panel on climate change dell & # 39; UN. And more recently, research has confirmed these suspicions.

If you read over the headline and down in the history of the New York Times – which is actually quite good – you'll see that the new article is by no means a research article that presents a major new advancement. It is actually an assessment based on the previous original research of the state of knowledge on the rising ocean heat content, or "OHC", as scientists label it. And as the assessment concludes, "Many lines of evidence from four independent groups now suggest a stronger OHC warming observed."

Based on much of the coverage I met today, one could easily conclude that the new assessment produced dramatic new discoveries. But the results have actually been accumulated for some years – as well as those titles, some of them quite dramatic. Now, the authors of the new assessment have brought together more strands of previous research to provide a clearer picture of what is currently known.

That picture shows that the oceans are warming 40 percent faster than estimated by the U.N. And things are getting worse and worse. As Trenberth, one of the authors, today sends an e-mail to me, "There are clear signs of acceleration."

The best estimates of how much global warming is going in the oceans is based in part on new ways of bringing together data from different sources. Since the early 2000s, accurate data have been provided by a modern network of floating ocean heat sensors, called the Argo network. But first, information was collected from less accurate sensors called expendable bathythermographs.

Due to inaccuracies, data from previous sensors contained biases. Thanks to recent research, scientists have found ways to tackle this problem, providing a better picture of how much heat the oceans have accumulated compared to the past.

The picture has also been improved by new ways of dealing with another irritating problem: in the past, larger portions of the oceans were not monitored than today. "The oceans are not well observed as we go back in time," notes Trenberth.

In the past, scientists have tried to tackle it using various strategies to fill the gaps. But these tended to produce excessively conservative estimates. More recently, satellite observations and computer modeling have helped to improve estimates of what has happened in unmonitored areas of the oceans.

And yet other researchers have analyzed oceanic factors that are influenced by ocean temperature to derive independent estimates of how ocean heat reserves have changed over time.

Overall, the estimates derived from these studies are in line with what the climate models have said. The models tended to indicate more warming of the ocean than what was observed, and this discrepancy had given fodder to critics of the science of climate change. But now, Trenberth and his fellow authors state that the discrepancy has largely disappeared.

One of the conclusions that make us reflect on the new assessment are the likely consequences of not being able to escape from the usual scenario of high emissions of heat trapped greenhouse gases. The model projections – which we now know have been aligned with the observations – show that the likely amount of ocean warming "would have a greater impact on ocean ecosystems and the rise in sea level through expansion thermal, "the scientists write.

When combining the estimates of thermal expansion with the increase in sea level projected by the melting of glaciers and ice sheets, it comes out with numbers that "herald very negative consequences for many coastal regions" Trenberth told me in an e-mail.

My point of writing for all of this today is to emphasize that if you pay too much attention to the titles, you might have the impression that science takes place in discrete bursts of new dramatic research results. In fact, most of the time, research progresses incrementally, with several groups of scientists investigating a particular issue independently and often in different ways. A study usually does not provide a definitive view of a phenomenon. More results are needed – and sometimes a group of scientists combining the pieces of the puzzle together – to produce a clearer and more convincing image.


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