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

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There’s been good evidence that the oceans were heating up faster than thought. Now, scientists have fitted the puzzle pieces together.

The trend in the amount of ocean heat is shown for the period 1993 to 2015. Yellow, orange and red tones show locations where ocean heat has increased. (Source: Cheng, Lijing & NCAR. Last modified 10 May 2017. "The Climate Data Guide: Ocean temperature analysis and heat content estimate from Institute of Atmospheric Physics." Retrieved from https://climatedataguide.ucar.edu/climate-data/ocean-temperature-analysis-and-heat-content-estimate-institute-atmospheric-physics.)

The trend in the amount of heat in the oceans is shown for the period 1993 to 2015. Yellow, orange and red tones show locations where ocean heat has increased. (Source: Lijing Cheng & NCAR. Retrieved from https://climatedataguide.ucar.edu/climate-data/ocean-temperature-analysis-and-heat-content-estimate-institute-atmospheric-physics.)

So this morning, as I’m drinking my coffee and perusing news headlines, I see this in the New York Times: “Ocean Warming Is Accelerating Faster Than Thought, New Research Finds.”

The story was about a new paper published Thursday in the journal Science titled, “How fast are the oceans warming?”

This is a big deal, because human-caused global warming doesn’t affect just the land surface. In fact, more than 90 percent of global warming’s heat is absorbed in the oceans. That has helped prevent much steeper increases in temperature on land.

But all that heat going into the oceans isn’t really a benign phenomenon. By causing ocean waters to expand, it contributes to sea level rise. The heat also can make storms more destructive, and it’s putting enormous stress on ocean ecosystems — which we depend on heavily for food.

And in the long run, what goes into the oceans doesn’t all stay in the oceans. Heat eventually comes out of the water to contribute to warming atmospheric temperatures around the globe.

So knowing exactly how much heat is going in is very important. With that in mind, I checked out other stories about the new paper in Science, and I saw that many featured similar headlines as the N.Y. Times.

More about the scientific paper in a minute. But first, I have to say that I realized I had seen very similar headlines before. Just this past October, for example, I saw this in Scientific American: “The Oceans Are Heating Up Faster Than Expected.” According to the story, a “new study published yesterday in the journal Nature concluded that the global oceans may be absorbing up to 60 percent more heat since the 1990s than older estimates had found.”

And nearly two years ago, the Washington Post ran this headline: “The world’s oceans are storing up staggering amounts of heat — and it’s even more than we thought.”  That was based on a study published in the journal Science Advances. In a press release about it, study co-author Keven Trenberth of the National Center for Atmospheric Research was quoted as saying that “the planet is warming quite a lot more than we thought.”

Hmmm. Two years ago we already knew that the planet was warming quite a lot more than we thought. So what’s up with today’s headlines, which seem to suggest that we didn’t know this?

For quite awhile now, scientists have actually had good reasons to believe the oceans have been taking up more global warming heat than was estimated in a major report in 2014 from the U.N.’s Intergovernmental Panel on Climate Change. And more recently, research has been confirming those suspicions.

If you read beyond the headline and down into that New York Times story — which actually is quite good — you’ll see that the new paper isn’t at all a research article presenting a major new advance. It’s actually an assessment based on previous original research of the state of knowledge about rising ocean heat content, or “OHC,” as scientists label it. And as the assessment concludes, “Multiple lines of evidence from four independent groups thus now suggest a stronger observed OHC warming.”

Based on a lot of the coverage I encountered today, you might easily conclude that the new assessment produced dramatic new findings. But the findings have actually been piling up for a few years — as have those headlines, some of them quite dramatic. Now, the authors of the new assessment have pulled multiple strands of previous research together to provide a clearer picture of what’s currently known.

That picture shows that the oceans are heating up 40 percent faster than what the U.N. report estimated. And things are getting increasingly worse. As Trenberth, one of the authors, put it in an email to me today, “There are clear signs of acceleration.”

The better estimates of how much global warming heat is going into the oceans is based in part on new ways of piecing 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 prior to that, information was collected by less accurate sensors called expendable bathythermographs.

Because of inaccuracies, the data from the older sensors contained biases. Thanks to recent research, scientists have found ways to deal with this issue, providing a better picture of just how much more heat the oceans have been sopping up compared to the past.

The picture has also been improved by new ways of dealing with another vexing issue: In the past, larger portions of the oceans went unmonitored than today. “The oceans are not well observed as we go back in time,” notes Trenberth.

In the past, scientists tried to deal with this using various strategies for filling the gaps. But these tended to produce overly conservative estimates. More recently, satellite observations and computer modeling have helped improve estimates of  what has been going on in largely unmonitored areas of the oceans.

And still other researchers have analyzed ocean factors that are influenced by ocean temperature to derive independent estimates of how the ocean’s store of heat  has changed over time.

Overall, the estimates derived by these studies are in line with what climate models have been saying. The models have tended to indicate more ocean warming than what had been observed, and that discrepancy had given fodder for critics of climate change science. But now, Trenberth and his fellow authors say that discrepancy is largely gone.

One of the sobering conclusions of the new assessment is the likely consequences of failing to get off the business-as-usual scenario of high emissions of heat-trapping greenhouse gases. Model projections — which we now know have been line with observations — show that the likely amount of ocean warming “would have major impacts on ocean ecosystems and sea level rise through thermal expansion,” the scientists write.

When you combine estimates of thermal expansion with projected sea level rise from melting glaciers and ice sheets, you come up with numbers that “portend very bad consequences for many coastal regions,” Trenberth told me in an email message.

My point in writing all of this today is to point out that if you pay too close attention to headlines, you might get the impression that science happens in discrete bursts of dramatic new research findings. In fact, most of the time, research progresses incrementally, with different groups of scientists probing at a particular issue independently and often in different ways. One study usually doesn’t provide definitive insight into a phenomenon. It takes multiple findings — and sometimes a group of scientists fitting those puzzle pieces together — to produce a clearer, convincing picture.



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Ecology

Whale Sharks, Earth’s Largest Fish, Also Commonly Eat Plants

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whale shark

(Credit: Lindsey Lu/Shutterstock)

Whale sharks, the world’s largest fish, eat significant amounts of plants and algae, scientists reveal in a surprising new study out today in the journal Ecological Monographs.

The sharks aren’t necessarily vegetarians, but they can sometimes go for weeks or month without eating, say researchers from Japan. The vegetative fare may be how the fish fill in their diets when prey is scarce.

“Whale sharks are a globally threatened but very poorly understood species,” said Alex Wyatt, a marine ecologist at the University of Tokyo in Japan, who led the new research. “Despite their massive size… we still know relatively little about them.”

A Whale of A Shark

Whale sharks are indeed massive. The polka-dotted fish can grow up to about 40 feet in length and weigh as much as 47,000 pounds, nearly as much as four African elephants, Earth’s largest land animal, combined. The sharks stick to warm, tropical waters and tend to aggregate in locations where they take can advantage of prime feeding opportunities.

Whale sharks gather in the Gulf of Mexico when fish are spawning, for example, and at Christmas Island in the Indian Ocean the sharks show up in huge numbers during the annual mass spawning of red land crabs. Beyond what they eat at these yearly feasts, though, scientists know little about whale sharks’ diets.

To illuminate the mystery, Wyatt and colleagues tracked stable forms of carbon and nitrogen in the sharks’ tissues, which allowed them to track what and when they’d eaten. The team followed two populations: one group of five captive individuals that were part of the Okinawa Churaumi Aquarium and a second group of eight wild sharks that had become entangled in fishing nets off the coast of Okinawa. The team took blood samples and other measurements of the wild whale sharks as they freed them from the nets. The analysis gave the researchers a picture of the sharks’ overall health, including what they ate and how long it’d been since their last meal.

Diverse Diet

In a surprise find, all of the wild sharks the researchers evaluated had recently eaten some sort of plant matter. What’s more, many of them had experienced a period of prolonged food scarcity in the recent past. The researchers suspect the sharks may fast during long migrations and rely on plants and algae for sustenance when other food is scarce.

“We were able to identify two feeding strategies (oceanic or coastal), evidence of prevalent starvation and the first direct evidence of herbivory by the species,” Wyatt said.

The sharks’ diets fell smack between a pure herbivore and a pure carnivore, the researchers report, meaning whale sharks are actually omnivores. They may not be the only ones. Research from another team recently showed captive bonnethead sharks are able to live off a mostly vegetarian diet of seagrass and squid.

“Omnivory in sharks may be more common than previously recognized,” Wyatt said.



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Ecology

This Robot Dog Teaches Itself New Tricks

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robot dog ANYmal

ANYmal walks like a dog and looks like a dog thanks to its extensive, computerized dog-training courses. (Credit: Hwangbo et al., Sci. Robot. 4, eaau5872 (2019))

Now that’s a headline, right? It’s got a robot dog, plays off a well-known phrase and piques curiosity. Best of all: It’s also accurate! Sort of.

According to a paper today in Science Robotics, an international team of engineers created a way for legged robots — inspired by and physically similar to quadrupedal canines — to use machine learning techniques to learn better ways to move around and adapt to a given environment. As proof, you can watch one such robot “withstanding abuse from their human creators,” as the official caption describes it.

 

Robot Dog Days

Now, I know what you may be thinking: This is dangerously close to that one Black Mirror episode, with the killer robot dogs. Well, as it turns out, it’s actually closer to those other Black Mirror episodes about virtual spaces.

That’s because the “training sessions,” where the dogs did all their learning, took place within a computer. “We introduce a method for training a neural network policy in simulation,” the authors write, “and transferring it to a state-of-the-art legged system, thereby leveraging fast, automated, and cost-effective data generation schemes.” The artificial intelligence — here applied to a specific dog-sized machine named the ANYmal, but the method should work on any machine — learns all its tricks in the digital world, where there are no complicated and expensive parts to engineer and replace, then shows off its abilities in the real world.

Using this technique, the researchers improve on all previous attempts to manipulate such robots, achieving a new level of control and efficiency. In particular, ANYmal can now run up to 25 percent faster than ever, and it recovers from all fall it experienced in real-world testing. (Hence the abuse, above.)

A Robot’s Best Friend

Despite the Black Mirror comparisons, this stuff is more cool and exciting than depressing and unsettling. The authors themselves point out the promise of such mobile technology: “Legged robots may one day rescue people in forests and mountains, climb stairs to carry payloads in construction sites, inspect unstructured underground tunnels, and explore other planets.”

And because the virtual training regimen — all of which took place on simple personal computers and never exceeded 11 hours — was sped up, running about 1,000 times faster than real-time, this method of learning is cheap and gets results relatively quickly.

Of course, other machines will still need their own training sessions for now, and there are other bugs to work out before the technology can achieve those lofty goals. Still, we now have a robot dog that trained themselves to improve their running form and get back up from any kind of a fall — an uplifting and inspirational message that proves just how unlike Black Mirror this really is.



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Ecology

Over 60 Percent of Wild Coffee Species Are at Risk of Extinction

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Coffee beans

(Credit: Ilja Generalov/Shutterstock)

For all those that rely on that cup of coffee to get you going in the morning, here’s another eye-opener: A majority of wild coffee might be going extinct.

That info is courtesy of a new study finding roughly 60 percent of wild coffee species are at risk of going extinct. We don’t drink these wild, unsavory strains often, but they could help our beloved arabica and robusta beans adapt to climate change, resist pests and ward off diseases.

The study on coffee extinction risks, which examined 124 different species, was published today in the journal Science Advances.

Brewed to Perfection

Your poison might be lattes, frappuccinos or macchiatos, but most coffee drinks have one thing in common: their beans. The famous arabica species makes up 60 percent of the world’s traded coffee, with the robusta strain trailing behind at 40 percent. People have been cultivating them for hundreds of years for their smooth, mild taste.

Recent increases in droughts and diseases, though, are putting our beloved beans at risk. But luckily, there are species of wild coffee with hardier traits that allow them to survive in tough conditions. Through interbreeding and hybridization, we could mix wild and domesticated species to create coffee that is both tasty and resilient.

To do that, though, we need to know the prevalence and growth rates of wild breeds. So Aaron P. Davis, a senior research leader at the Royal Botanic Gardens in the United Kingdom, set out to study the extinction risks for all 124 known species of coffee.

Elevated Extinction

With a team of researchers, Davis analyzed over 5,000 data points, coming mostly from species records and field observations. They looked at factors like population decline, deforestation and overall habitat quality. In all, they found that 75 species of wild coffee, or 60 percent, are at risk of extinction. They’ve grown and adapted to life in the wild for centuries, but due to deforestation, their natural habitats and populations continue to dwindle. Habitat loss ranks among the most dire threats to most of the endangered species, the researchers say.

To combat these numbers, and ensure the long-term survival of arabica and robusta, the researchers outline two necessary actions: collect wild strains for hybridization and make sure they’re growing in protected areas, like national parks and nature reserves. But in their research, they found that 45 percent of wild species aren’t being collected and 28 percent aren’t growing in protected areas.

Just because they’re warding off pests, plant diseases and adjusting to climate change, doesn’t mean that they’re immune to extinction. Many wild species are growing sparsely and in limited locations, and if we don’t stockpile and protect them, our precious brews could be at risk. And consequently, our morning-time sanity.



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