Scientists find far higher than expected rate of underwater glacial melting

Scientists find far higher than expected rate of underwater glacial melting

SOURCE: Phys.org DATE: January 29, 2020 SNIP: Tidewater glaciers, the massive rivers of ice that end in the ocean, may be melting underwater much faster than previously thought, according to a Rutgers co-authored study that used robotic kayaks. The findings, which challenge current frameworks for analyzing ocean-glacier interactions, have implications for the rest of the world’s tidewater glaciers, whose rapid retreat is contributing to sea-level rise. The study, published in the journal Geophysical Research Letters, surveyed the ocean in front of 20-mile-long LeConte Glacier in Alaska. The seaborne robots made it possible for the first time to analyze plumes of meltwater, the water released when snow or ice melts, where glaciers meet the ocean. It is a dangerous area for ships because of ice calving—when falling slabs of ice that break from glaciers crash into the water and spawn huge waves. “With the kayaks, we found a surprising signal of melting: Layers of concentrated meltwater intruding into the ocean that reveal the critical importance of a process typically neglected when modeling or estimating melt rates,” said lead author Rebecca Jackson, a physical oceanographer and assistant professor in the Department of Marine and Coastal Sciences in the School of Environmental and Biological Sciences at Rutgers University-New Brunswick. Two kinds of underwater melting occur near glaciers. Where freshwater discharge drains at the base of a glacier (from upstream melt on the glacier’s surface), vigorous plumes result in discharge-driven melting. Away from these discharge outlets, the glacier melts directly into the ocean waters in a regime called ambient melting. The study follows one published last year in the journal Science that measured...
Warm Water ‘Blob’ Led to Fatal Whale Entanglements. Here’s Why

Warm Water ‘Blob’ Led to Fatal Whale Entanglements. Here’s Why

SOURCE: KQED DATE: January 27, 2020 SNIP: Much of the West Coast’s ocean bounty comes courtesy of the California Current, an up-welling of cold, nutrient-rich water in the late winter and early spring. “That stimulates the development of a rich food web that is sort of like a Serengeti of the ocean,” said Jarrod Santora, a research ecologist at UCSC and the National Oceanic and Atmospheric Administration. Humpback whales travel all the way from Hawaii to feast in the cold waters off the coast. But between the years 2014 and 2016, a severe marine heat wave, nicknamed “the blob,” coincided with an unprecedented number of humpback fatalities stemming from entanglements with fishing gear. In a new paper published Monday, Santora and colleagues say they know why: Warm water pushed the cold water into a long narrow band along the coast. Since cool water is where the whales forage for food, finding it only along the coast was like discovering all the restaurants in town are closed, except along one narrow strip. Unfortunately, the compression of feeding grounds coincided with crabbing season, so that the new dining hotspots were also littered with ropes connected to crab pots. NOAA tracks the number of whales entangled each year, and prior to 2014, Pacific Coast whale entanglements numbered about 10 per year on average. But they jumped to 30 in 2014 and skyrocketed to 53 in 2015, then 56 in 2016. The numbers dropped the next two years but were still high historically. The spate of deaths prompted the Center for Biological Diversity to file a lawsuit against the California Department of Fish...
Huge ‘hot blob’ in Pacific Ocean killed nearly a million seabirds

Huge ‘hot blob’ in Pacific Ocean killed nearly a million seabirds

SOURCE: The Guardian DATE: January 16, 2020 SNIP: A million seabirds died in less than a year as a result of a giant “blob” of hot ocean water off the coast of New Zealand, according to new research. A study released by the University of Washington found the birds, called the common murre, probably died of starvation between the summer of 2015 and the spring of 2016. Most dead seabirds never wash ashore, so while 62,000 dead or dying murres were found along the coasts of Alaska, Washington, Oregon and California, researchers estimate the total number is closer to 1 million. Alaska saw the most birds wash up. In Prince William Sound in southern Alaska, more than 4,500 bird carcasses were found every kilometer, or 0.62 miles. The blob stems from a years-long severe marine heatwave, believed to be caused by an anticyclone weather system that first appeared in 2013. A weather phenomenon known as El Niño accelerated the warming temperatures beginning in 2015 and, by 2016, the rising heat resulted in water temperatures nearly 11F (6C) above average. Anticyclones form when a mass of air cools, contracts and becomes more dense, increasing the weight of the atmosphere and the surface air pressure. Heat maps at the time showed a massive red blob growing, spanning more than 380,000 sq miles (1 million sq km). That’s nearly 1.5 times the size of Texas or four times larger than New Zealand. The study found that the murres mostly likely starved to death. The seabird must eat half its body weight to survive, but food grew scarce amid intense competition from other...
Ocean Warming Is Speeding Up, with Devastating Consequences, Study Shows

Ocean Warming Is Speeding Up, with Devastating Consequences, Study Shows

SOURCE: Inside Climate News DATE: January 14, 2020 SNIP: The world’s oceans are warming at a rapidly increasing pace, new research shows, and the heat is having devastating effects on marine life and intensifying extreme weather. Last year, the oceans were warmer than any time since measurements began over 60 years ago, according to a study published Monday in the journal Advances in Atmospheric Sciences. While global surface temperature measurements go back farther in time, the measurement of ocean heat content is considered one of the most effective ways to show how fast Earth is warming because more than 90 percent of the heat trapped by greenhouse gases goes into the oceans. The new study, the first to analyze ocean temperatures for 2019, was based on two independent data sets and used a new way of filling data gaps to measure ocean temperatures going back to the 1950s. When the scientists compared ocean temperature data from the last three decades (1987-2019) to the three decades before that (1955-1986), they found the rate of warming had increased 450 percent, “reflecting a major increase in the rate of global climate change.” Measured by a common energy unit used in physics, the oceans absorbed 228 sextillion joules of heat in the past 25 years. That’s equivalent to adding the energy of 3.6 billion Hiroshima-size atom bomb explosions to the oceans, said the study’s lead author, Lijing Cheng, with the International Center for Climate and Environmental Sciences at the Institute of Atmospheric Physics. The warming of the oceans has widespread effects. It causes marine heat waves that kill fish and coral reefs, fuels...
Ocean temperatures hit record high as rate of heating accelerates

Ocean temperatures hit record high as rate of heating accelerates

SOURCE: The Guardian DATE: January 13, 2020 SNIP: The heat in the world’s oceans reached a new record level in 2019, showing “irrefutable and accelerating” heating of the planet. The world’s oceans are the clearest measure of the climate emergency because they absorb more than 90% of the heat trapped by the greenhouse gases emitted by fossil fuel burning, forest destruction and other human activities. The new analysis shows the past five years are the top five warmest years recorded in the ocean and the past 10 years are also the top 10 years on record. The amount of heat being added to the oceans is equivalent to every person on the planet running 100 microwave ovens all day and all night. Hotter oceans lead to more severe storms and disrupt the water cycle, meaning more floods, droughts and wildfires, as well as an inexorable rise in sea level. Higher temperatures are also harming life in the seas, with the number of marine heatwaves increasing sharply. The most common measure of global heating is the average surface air temperature, as this is where people live. But natural climate phenomena such as El Niño events mean this can be quite variable from year to year. “The oceans are really what tells you how fast the Earth is warming,” said Prof John Abraham at the University of St Thomas, in Minnesota, US, and one of the team behind the new analysis. “Using the oceans, we see a continued, uninterrupted and accelerating warming rate of planet Earth. This is dire news.” “We found that 2019 was not only the warmest year on...