Ocean Heat Waves Are Directly Linked to Climate Change

Ocean Heat Waves Are Directly Linked to Climate Change

SOURCE: New York Times and Science DATE: September 24, 2020 SNIP: Six years ago, a huge part of the Pacific Ocean near North America quickly warmed, reaching temperatures more than 5 degrees Fahrenheit above normal. Nicknamed “the blob,” it persisted for two years, with devastating impacts on marine life, including sea lions and salmon. The blob was a marine heat wave, the oceanic equivalent of a deadly summer atmospheric one. It was far from a solitary event: Tens of thousands have occurred in the past four decades, although most are far smaller and last for days rather than years. The largest and longest ones have occurred with increasing frequency over time. On Thursday, scientists revealed the culprit. Climate change, they said, is making severe marine heat waves much more likely. The study, published in the journal Science, looked at the blob and six other large events around the world, including one in the Northwest Atlantic in 2012. Human-caused global warming made these events at least 20 times more likely, the researchers found. “Some of these couldn’t even have occurred without climate change,” said Charlotte Laufkötter, a marine scientist at the University of Bern in Switzerland and the lead author of the study. In a world with no human-caused warming, a large marine heat wave would have had about a one-tenth of 1 percent chance of occurring in any given year — what is called a thousand-year event. But with the current rate of global warming, an ocean heat wave like that could soon have as much as a 10 percent chance of occurring, the study found. Dr. Laufkötter said...
The water is so hot in Alaska it’s killing large numbers of salmon

The water is so hot in Alaska it’s killing large numbers of salmon

SOURCE: CNN DATE: August 17, 2019 SNIP: Alaska has been in the throes of an unprecedented heat wave this summer, and the heat stress is killing salmon in large numbers. Scientists have observed die-offs of several varieties of Alaskan salmon, including sockeye, chum and pink salmon. Stephanie Quinn-Davidson, director of the Yukon Inter-Tribal Fish Commission, told CNN she took a group of scientists on an expedition along Alaska’s Koyokuk River at the end of July, after locals alerted her to salmon die-offs on the stream. She and the other scientists counted 850 dead unspawned salmon on that expedition, although they estimated the total was likely four to 10 times larger. They looked for signs of lesions, parasites and infections, but came up empty. Nearly all the salmon they found had “beautiful eggs still inside them,” she said. Because the die-off coincided with the heat wave, they concluded that heat stress was the cause of the mass deaths. Quinn-Davidson said she’d been working as a scientist for eight years and had “never heard of anything to this extent before.” “I’m not sure people expected how large a die-off we’d see on these rivers,” she said. The water temperatures have breaking records at the same time as the air temperatures, according to Sue Mauger, the science director for the Cook Inletkeeper. Scientists have been tracking stream temperatures around the Cook Inlet, located south of Anchorage, since 2002. They’ve never recorded a temperature above 76 degrees Fahrenheit. Until now. On July 7, a major salmon stream on the west side of the Cook Inlet registered 81.7 degrees. Mauger said she and her...
Increased frequency of and population exposure to extreme heat index days in the United States during the 21st century

Increased frequency of and population exposure to extreme heat index days in the United States during the 21st century

SOURCE: IOP Science and Think Progress DATE: July 16, 2019 SNIP: A peer-reviewed study published this week warns that if we don’t reverse emissions trends quickly and sharply, we will see a rise in unprecedented heat waves that will “break” the National Weather Service’s heat index scale. The researchers warn we will face extended scorchers more brutal than the United States has ever experienced before. In several decades, parts of Florida and Texas could experience a heat index for five or more months per year exceeding 100 degrees, “with most of these days even surpassing 105 degrees.” The administration’s own studies confirm this. Typical five-day heat waves in the U.S. will be 12 degrees warmer by mid-century alone, according to the U.S. National Climate Assessment (NCA), which the White House itself reviewed and approved last November. From the report: By mid-21st century (2036–2065) under both emissions scenarios, the annual numbers of days with heat indices exceeding 37.8 °C (100 °F) and 40.6 °C (105 °F) are projected to double and triple, respectively, compared to a 1971–2000 baseline. In this timeframe, more than 25% of the US by area would experience no analog conditions an average of once or more annually and the mean duration of the longest extreme heat index event in an average year would be approximately double that of the historical baseline. By late century (2070–2099) with a high emissions scenario, there are four-fold and eight-fold increases from late 20th century conditions in the annual numbers of days with heat indices exceeding 37.8 °C and 40.6 °C, respectively; 63% of the country would experience no analog conditions...
Climate Change Is Having a Major Impact on Global Health

Climate Change Is Having a Major Impact on Global Health

SOURCE: Scientific American DATE: March 1, 2019 SNIP: Warming temperatures do not only threaten lives directly. They also cause billions of hours of lost labor, enhance conditions for the spread of infectious diseases and reduce crop yields, according to a recent report. The report, published last December in the Lancet, represents the latest findings of the Lancet Countdown—a coalition of international research organizations collaborating with the World Health Organization and the World Meteorological Organization. The group tracks the health impacts of—and government responses to—climate change. “It affects everyone around the world—every single person, every single population. No country is immune,” says Nick Watts, executive director of the Lancet Countdown and one of many co-authors of the report. “We’ve been seeing these impacts for some time now.” The report found that millions of people worldwide are vulnerable to heat-related disease and death and that populations in Europe and the eastern Mediterranean are especially susceptible—most likely because they have more elderly people living in urban areas. Adults older than 65 are particularly at risk, as are those with chronic illnesses such as heart disease or diabetes. Places where humans tend to live are exposed to an average temperature change that is more than twice the global average—0.8 versus 0.3 degree Celsius (graphic). There were 157 million more “heat wave exposure events” (one heat wave experienced by one person) in 2017 than in 2000. Compared with 1986 to 2005, each person was exposed to, on average, 1.4 more days of heat wave per year from 2000 to 2017. That may not seem like a lot, but as Watts notes, “someone who is...
Australia’s extreme heat is sign of things to come, scientists warn

Australia’s extreme heat is sign of things to come, scientists warn

SOURCE: The Guardian DATE: February 1, 2019 SNIP: Australia sweltered through the hottest month in its history in January, spurring mass deaths of fish, fire warnings and concerns among climate scientists that extreme heat is hitting faster and harder than anticipated. For the first time since records began, the country’s mean temperature in January exceeded 30C (86F), according to the Bureau of Meteorology (BoM), which said daily extremes – in some places just short of 50C – were unprecedented. “There’s been so many records it’s really hard to count,” said Andrew Watkins, a senior climatologist at BoM, after January registered Australia’s warmest month for mean, maximum and minimum temperatures. This followed the country’s warmest December on record, with heatwaves in every Australian state and territory. Climate change is the long-term driver. “The warming trend which has seen Australian temperatures increase by more than 1C in the last 100 years also contributed to the unusually warm conditions,” Watkins said. The bureau’s monthly report said the heatwaves were unprecedented in their scale and duration. The highest temperatures of the month were recorded in Augusta on the south-west coast, where thermometers registered 49.5C , but the most relentless heat was in Birdsville, Queensland, which endured 10 consecutive days above...