The human footprint continues to expand, with three quarters of earth’s land surface now experiencing measurable pressures from buildings, roads, crops, pastures and other human structures and activities, according to a new report. But the report also finds an encouraging trend: In recent years, growth in the footprint has lagged far behind population and economic growth.
East Africa’s rift valley is considered by many to be the cradle of humanity. In the Turkana region of northwest Kenya, researchers Christopher Lepre and Tanzhuo Liu of Columbia University’s Lamont-Doherty Earth Observatory are cooperating with colleagues to study questions of human evolution, from the creation of the earliest stone tools to climate swings that have affected developing civilizations.
Who were our earliest ancestors? How and when did they evolve into modern humans? And how do we define “human,” anyway? Scientists are exploring Kenya’s Lake Turkana basin to help answer these questions.
On a ledge just inside the lip of Chile’s Quizapu volcanic crater, Philipp Ruprecht was furiously digging a trench. Here at an elevation of 10,000 feet, a 1,000-foot plunge loomed just yards away, and wind was whipping dust off his shovel. But the volcanologist was excited. Ruprecht had just found this spot, topped with undisturbed wedding-cake layers of fine, black material that the crater had vomited from the deep earth some 84 years ago. Samples from the currently inactive site might shed light on its exceedingly violent behavior.
High in the southern Andes, Chile’s Quizapu crater is one of South America’s most fearsome geologic features. In 1846, it was the source of one the continent’s largest historically recorded lava flows. In 1932, it produced one of the largest recorded volcanic blasts. The volcano is currently inactive, but could revive at any time. What is next?
A study out yesterday says that the lives of up to 13 million people in the United States may be disrupted by sea-level rise in the next century. But another study says that while much hard infrastructure like houses, piers, seawalls and roads may have to be kissed goodbye, some 70 percent of natural landforms along the Northeast Coast may be able to adjust themselves, and not suffer inundation.
Forests in the south-central United States are some of the country’s most productive and diverse. They also sit in a warming “hole”—an area where the progressive rise in temperature affecting most of the continent hasn’t yet taken hold. A team from Columbia University’s Lamont-Doherty Earth Observatory is studying how these forests might shift—or even disappear—when climate change does catch up with them, as expected.
One foggy spring morning just after a hard rain, Park Williams was tromping through the woods deep in Arkansas’ Ozark Mountains. Toiling down a steep slope, he supposedly was keeping a simultaneous eye out for rattlesnakes, copperheads, poison ivy and big old trees. Williams seemed mostly focused on the trees, though; attention to the other stuff was just slowing him down. Williams studies how forests react to changes in climate, and the Ozarks’ deeply dissected hills and hollers—what some might refer to as typical hillbilly country—are a kind of ground zero for this.
Last Thursday, thousands of people on the Eastern Seaboard felt the earth tremble. Seismologists at Columbia University’s Lamont-Doherty Earth Observatory quickly concluded it was not an earthquake, but a military exercise.
Twenty thousand years ago, low concentrations of carbon dioxide in the atmosphere allowed the earth to fall into the grip of an ice age. But despite decades of research, the reasons why levels of the greenhouse gas were so low then have been difficult to piece together. New research, published today in the leading journal Nature, shows that a big part of the answer lies at the bottom of the world.