Videos sent to me by a scientist friend describe field investigations into a period that might be a model for our own.
The PETM, Paleocene-Eocene Thermal Maximum.
Thinking in geologic time is a skill humans may have to learn to survive the current era.
Above, a moulin recorded in Southwest Greenland, summer 2014.
A cerulean lake consisting of glacial meltwater on the surface of the Greenland ice sheet, located about 18 miles from where the Store Glacier meets the sea in west Greenland, briefly became one of the world’s tallest waterfalls during the course of five hours in July 2018.
The waterfall, like many others on the ice sheet’s surface, was triggered by cracks in the ice sheet. In the case of this one meltwater lake that scientists closely observed in July 2018, the water cascaded more than 3,200 feet to the underbelly of the glacier, where the ice meets bedrock. There, the water can help lubricate the base of the ice sheet, helping the ice move faster toward the sea.
The observations of scientists, armed with aerial drones and other high-tech equipment, of the partial lake drainage that resulted could help researchers better understand how surface melting of the ice sheet could affect its melt rate, and improve global sea level rise projections.
Scientists are keenly interested in how meltwater on the surface of the Greenland ice sheet — the largest contributor to global sea level rise — acts to speed up the movement of ice toward the sea by lubricating the underside of the ice surface. The new study, published Monday in Proceedings of the National Academy of Sciences, suggests that scientists are underestimating the number of melt ponds that partially, and rapidly, drain into the ice sheet each year. This means tweaks may be needed to the computer models used to predict sea level rise from Greenland.
TOMBWA, Angola — His ancestors were Portuguese colonialists who settled on this otherworldly stretch of coast, wedged between a vast desert and the southern Atlantic. They came looking for the one thing this barren region had in abundance: fish.
By the time Mario Carceija Santos was getting into the fishing business half a century later, in the 1990s, Angola had won independence and the town of Tombwa was thriving. There were 20 fish factories strung along the bay, a constellation of churches and schools, a cinema hall built in art deco, and, in the central plaza, massive drying racks for the tons upon tons of fish hauled out of the sea.
Since then, Tombwa’s fortunes have plummeted; Santos’s factory is one of just two remaining. The cinema hall is shuttered. Kids run around town barefoot instead of going to school. The central plaza is overgrown by weeds, its statue of a proud fisherman covered in bird droppings.
“Six or seven species have disappeared almost entirely from here, sardines and anchovies included — the ones these factories were made for processing,” Santos said in his office, after inspecting the day’s catch.
“We’ll just have to close shop at some point.”
The gradual disappearance of fish is a death knell for Tombwa, a town of 50,000 that has little else to offer residents. The approaching bust is the result of three powerful forces: Fish are suffocating in oxygen-depleted waters, huge foreign trawlers are grabbing what’s left, and the water is heating up far more rapidly here than almost anywhere else on the planet.
Click any temperature underlined in the story to convert between Celsius and Fahrenheit
Sea temperatures off the Angolan coast have risen 1.5 degrees Celsius — and possibly more — in the past century, according to a Washington Post analysis of National Oceanic and Atmospheric Administration data.
In recent years, multiple studies have identified the waters along Tombwa’s coast in particular as a fast-warming hot spot: In one independent analysis of satellite-based NOAA data, temperatures have risen nearly 2 degrees Celsius since 1982. That is more than three times the global average rate of ocean warming.
Continue reading “How Climate Warming Targets African Fishermen”
