It’s even hot underwater

“Hotter surface water can slow upwelling, a phenomenon that brings nutrients from deep in the water like nitrogen and phosphorus compounds toward the surface, feeding the plankton that form the foundation of the food pyramid. Roughly half of the fish in the world are caught in upwelling zones.

Hotter water also holds onto less oxygen, which can suffocate sea life. Earlier this year, thousands of dead menhaden fish washed up on the shores of Texas, due in large part to high water temperatures. The water itself becomes more acidic as it heats up, which can disrupt coral formation. And when the temperature rises too high, coral will expel the symbiotic algae that live in their tissues, turning completely white. This is called coral bleaching. All these effects of hotter water temperatures can then make coral more vulnerable to disease.

Sargassum, a type of algae, has seen massive and growing blooms in the Caribbean Sea and Atlantic Ocean in recent years, but there’s been a record quantity this summer, enough to be seen from the sky, washing up on beaches from South America to Florida. As it rots, it emits smelly, toxic hydrogen sulfide gas. Higher water temperatures are likely a factor here as well.

It’s not clear yet exactly how the alarmingly hot waters of the Caribbean will affect seafood catches, but scientists warn that extreme marine heat has proven devastating to fisheries in the past.”

The world’s oceans are extremely hot. We’re about to find out what happens next.

“it’s not just the Atlantic; oceans all around the world are seeing stunningly high average temperatures right now. On the other side of the globe, the Pacific Ocean surface is also heating up as it enters the El Niño phase of its cycle. Together, these phenomena are poised to push the planet’s temperature to new highs.”

What’s killing the world’s biggest fish?

“The largest fish on Earth is a shark. Capable of reaching a length of up to 60 feet — roughly the height of a four-story building — whale sharks, named for their size, are so large that they make great whites look like minnows.

But even giants can disappear. Over the last several decades, more than half of all whale sharks have vanished from the ocean. Some populations have fallen by more than 60 percent.”

“A study in the journal Proceedings of the National Academy of Sciences reveals that cargo ships are likely a leading cause of whale shark deaths. Often, where you find high densities of these endangered fish, you also find shipping traffic, the authors found, and ships are already known to strike and kill these animals.”

“Whale sharks are not the only roadkill. Vast cargo vessels harm many species of marine giants, such as the endangered North Atlantic right whales, and some smaller creatures, like sea turtles. Ships also emit loud noises that disrupt marine life and spew planet-warming carbon dioxide into the atmosphere.

“Shipping is a serious problem for giants of the sea,” said Robert Harcourt, a marine ecologist at Macquarie University in Australia who was not affiliated with the study. “We have an economy that’s derived from moving things around the world in a way that’s not taking into account the cost to the environment.””

“A good step toward decreasing collisions is figuring out where animals are most at risk, and that’s where this new whale shark study comes in. Large ships are required to report their locations, and the authors compared those points to the movement of hundreds of whale sharks, which they had previously tagged with satellite trackers. (This is no easy feat: “You’ve gotta have some nice long fins, a good pair of lungs, and sprint after it underwater,” said David Sims, a marine ecologist at the University of Southampton and a study co-author.)

The results revealed just how vulnerable these fish are: More than 90 percent of the ocean’s surface area that whale sharks use overlaps with the routes of tankers, passenger ships, and fishing vessels. Whale sharks tend to congregate near the coast, where shipping is especially busy”

“many of the sharks’ tracking devices stopped working when the animals entered busy shipping lanes, perhaps because they were killed by ships. (Some trackers even showed sharks swimming into dense shipping routes and then sinking slowly to the seafloor — “the smoking gun for a lethal ship strike,” as Womersley and Sims wrote in The Conversation.)”

“Making oceans safer for marine giants is conceptually simple, and one option is to route ships away from animal hot spots.”

“Even just slowing ships down can make a huge difference. The chance that a cargo ship will kill a whale falls to below 50 percent when it’s moving at around half speed (10 knots, or 11.5 miles per hour), compared to nearly 100 percent when it’s moving more quickly, according to one 2006 study.”

“there’s a big drawback to ships slowing down or going on a different route: It takes longer to deliver goods. That’s one reason studies like this don’t always translate into shipping restrictions. That drawback also makes alternative approaches, such as designing quieter ships or adding wildlife deterrents or propeller guards, appealing (although the benefits of these technologies aren’t well established).”

Climate change is already making parts of the world unlivable

“Global average temperatures have already risen by 1.1 degrees Celsius, roughly 2 degrees Fahrenheit, leaving perilously little room for meeting the targets of the 2015 Paris climate agreement. The accord set a goal of limiting global warming to less than 2 degrees Celsius/3.6 degrees Farenheit compared to average temperatures before the industrial revolution in the 1800s. The agreement also set a more ambitious target of staying below 1.5°C/2.7°F.

Global warming has already raised global sea levels by 9 inches. It has left a distinct mark on extreme weather too, worsening heat waves, storm surges, and rainfall. Scientists can even quantify how much human-linked emissions of heat-trapping gases have made these events worse.”

“The natural world is passing some of the hard limits of what it can handle from climate change right now, leading to irreversible changes like extinction of species. “Ecosystems already reaching or surpassing hard adaptation limits include some warm water coral reefs, some coastal wetlands, some rainforests, and some polar and mountain ecosystems,” according to the report. Humans who are dependent on these ecosystems are deeply affected as well.”

“Sea level rise is forcing residents of small islands to permanently evacuate. At least five islands in the Pacific Ocean have been lost to higher water levels. Rising temperatures are changing rainfall patterns and melting snowpacks, limiting freshwater for drinking and agriculture. This is driving migrations around the world.”

“As bad as the situation is right now, climate change can still get much worse. Rising temperatures mean that many more areas of the world, spanning some of the most populated regions, will experience times when it’s too hot to survive.”

“More than 150 million people currently live on land that will be below the high-tide line by 2050.”

Sea Level To Rise One Foot by 2050, Says NOAA

“since 1968 the U.S. government’s National Flood Insurance Program (NFIP) has been subsidizing a significant number of its policyholders to build and live in flood-prone areas. As a result of losses outstripping its premiums, the NFIP is $20.5 billion in debt. In a recent article in Regulation, Peter Van Doren, a senior fellow at the libertarian Cato Institute, points out that the often highly concentrated nature of flood disasters would require private insurers to charge premiums amounting to 5 to 9 times the average claim in order to remain solvent. Few people would buy such expensive policies.

Last fall the NFIP launched its Risk Rating 2.0 program which is raising the rates for nearly 75 percent of its policyholders. Premiums may increase by as much as 18 percent per year for owner-occupied homes and 25 percent for second homes. Over time, such increases will incentivize people to move away from areas where the sea is engulfing their homes and businesses.

A growing body of research suggests that at least some Americans are beginning to factor sea level rise into their purchases of beachfront property.”

Climate scientists should pay more attention to fish poop. Really.

“The story goes something like this: Tiny marine organisms called phytoplankton absorb carbon from the water and air around them. As the plankton are eaten by increasingly larger creatures, the carbon then travels up the food chain and into fish. Those fish then release a lot of it back into the ocean through their poop, much of which sinks to the seafloor and can store away carbon for centuries. The scientific term for carbon storage is sequestration.

“We think this is one of the most effective carbon-sequestration mechanisms in the ocean,” Bianchi told Vox. “It reaches the deep layers, where carbon is sequestered for hundreds or thousands of years.”

Carbon that’s stored in the deep sea is carbon that’s not making the oceans more acidic or trapping heat in the atmosphere. In other words, fish poop could be a bulwark against climate change.

The problem is that commercial fishing has sliced the global fish population to a fraction of its former level. As scientists figure out the importance of fish poop, they’re also recognizing a new danger of large-scale fishing. Beyond putting ecosystems at risk, the industry is messing with big nutrient cycles — and perhaps eating into an important carbon sink.”

Why the record low Arctic sea ice this October is so alarming

“Changes in the ice are part of a larger “cascade effect,” as Webster describes it, in which delayed winter ice growth leads to thinner ice, which melts more easily in the summer months compared to older, thicker sea ice. This creates more open ocean.

This transformation contributes to both regional and global warming. Where a white sea ice surface would have reflected sunlight, the dark water absorbs heat, which further reduces ice growth. This change in albedo (or reflectivity) on sea and land in the Arctic is one of the main reasons the region is heating at twice the global average rate, according to the National Oceanic and Atmospheric Administration’s 2019 Arctic Report Card. According to the recent Nature Communications study, it will also be a significant contributor to global warming.

Near Greenland — which holds a massive ice sheet — the warming loop set off by sea ice loss has a minor effect on its warming, but not a substantial effect on the ice sheet itself, researchers found in a 2019 study in Geophysical Research Letters.

The sea ice shift could also impact seasonal weather, potentially intensifying extreme weather. However, Labe says the issue requires further research. “Scientists are actively studying the connections between Arctic sea ice loss and wintertime weather patterns in North America, Europe, and Asia,” he said. “However, these relationships remain highly uncertain in the scientific literature and for seasonal weather forecasts.”

For now, the plummeting sea ice volumes are a startling reminder of just how rapidly the planet is changing, and how dire the consequences of delaying radical cuts in greenhouse gas emissions will be.”