All rights reserved. Meltwater gushes from an ice cap on the island of Nordaustlandet, in Norway's Svalbard archipelago. We're armed with crampons, ice axes, rope, GPS receivers, and bear spray to ward off grizzlies, and we're trudging toward Sperry Glacier in Glacier National Park , Montana. I fall in step with Fagre and two other research scientists from the U. They're doing what they've been doing for more than a decade: measuring how the park's storied glaciers are melting. So far, the results have been positively chilling.
Since then the number has decreased to fewer than 30, and most of those remaining have shrunk in area by two-thirds. Fagre predicts that within 30 years most if not all of the park's namesake glaciers will disappear. Scientists who assess the planet's health see indisputable evidence that Earth has been getting warmer , in some cases rapidly. Most believe that human activity, in particular the burning of fossil fuels and the resulting buildup of greenhouse gases in the atmosphere, have influenced this warming trend.
It is their internal temperature that increases. We clearly see a warming between and Boykoff and Boykoff, ; Painter, ], and increasingly on social media platforms like Twitter [e. Accessed August 29, Download high-resolution image.
In the past decade scientists have documented record-high average annual surface temperatures and have been observing other signs of change all over the planet: in the distribution of ice, and in the salinity, levels, and temperatures of the oceans. He's only half joking. A trailside sign notes that since , Sperry Glacier has shrunk from more than acres hectares to acres hectares. Everywhere on Earth ice is changing.
The famed snows of Kilimanjaro have melted more than 80 percent since Glaciers in the Garhwal Himalaya in India are retreating so fast that researchers believe that most central and eastern Himalayan glaciers could virtually disappear by Arctic sea ice has thinned significantly over the past half century, and its extent has declined by about 10 percent in the past 30 years.
Glacial ice can range in age from several hundred to several hundreds of thousands years, making it valuable for climate research. To see a long-term climate. 6 days ago As the climate warms, how much, and how quickly, will Earth's glaciers melt? They're doing what they've been doing for more than a decade: measuring how the park's storied glaciers are melting. When President Taft created Glacier National Park in , it was home to an estimated.
NASA's repeated laser altimeter readings show the edges of Greenland's ice sheet shrinking. Spring freshwater ice breakup in the Northern Hemisphere now occurs nine days earlier than it did years ago, and autumn freeze-up ten days later. Thawing permafrost has caused the ground to subside more than 15 feet 4. From the Arctic to Peru, from Switzerland to the equatorial glaciers of Man Jaya in Indonesia, massive ice fields, monstrous glaciers, and sea ice are disappearing, fast.
When temperatures rise and ice melts, more water flows to the seas from glaciers and ice caps, and ocean water warms and expands in volume. This combination of effects has played the major role in raising average global sea level between four and eight inches 10 and 20 centimeters in the past hundred years, according to the Intergovernmental Panel on Climate Change IPCC.
Scientists point out that sea levels have risen and fallen substantially over Earth's 4. But the recent rate of global sea level rise has departed from the average rate of the past two to three thousand years and is rising more rapidly—about one-tenth of an inch a year. A continuation or acceleration of that trend has the potential to cause striking changes in the world's coastlines. In southern Louisiana coasts are literally sinking by about three feet a meter a century , a process called subsidence. A sinking coastline and a rising ocean combine to yield powerful effects.
It's like taking the global sea-level-rise problem and moving it along at fast-forward. The seventh-generation Cajun and manager of the South Lafourche Levee District navigates his truck down an unpaved mound of dirt that separates civilization from inundation, dry land from a swampy horizon. With his French-tinged lilt, Curole points to places where these bayous, swamps, and fishing villages portend a warmer world: his high school girlfriend's house partly submerged, a cemetery with water lapping against the white tombs, his grandfather's former hunting camp now afloat in a stand of skeleton oak snags.
Rising sea level, sinking land, eroding coasts, and temperamental storms are a fact of life for Curole. Even relatively small storm surges in the past two decades have overwhelmed the system of dikes, levees, and pump stations that he manages, upgraded in the s to forestall the Gulf of Mexico's relentless creep.
The current trend is consequential not only in coastal Louisiana but around the world. Never before have so many humans lived so close to the coasts: More than a hundred million people worldwide live within three feet a meter of mean sea level. Vulnerable to sea-level rise, Tuvalu, a small country in the South Pacific, has already begun formulating evacuation plans. Megacities where human populations have concentrated near coastal plains or river deltas—Shanghai, Bangkok, Jakarta, Tokyo, and New York—are at risk.
The projected economic and humanitarian impacts on low-lying, densely populated, and desperately poor countries like Bangladesh are potentially catastrophic. The scenarios are disturbing even in wealthy countries like the Netherlands, with nearly half its landmass already at or below sea level.
Rising sea level produces a cascade of effects. Bruce Douglas, a coastal researcher at Florida International University, calculates that every inch 2. Furthermore, when salt water intrudes into freshwater aquifers, it threatens sources of drinking water and makes raising crops problematic.
In the Nile Delta, where many of Egypt's crops are cultivated, widespread erosion and saltwater intrusion would be disastrous since the country contains little other arable land. In some places marvels of human engineering worsen effects from rising seas in a warming world.
The system of channels and levees along the Mississippi effectively stopped the millennia-old natural process of rebuilding the river delta with rich sediment deposits. In the s oil and gas companies began to dredge shipping and exploratory canals, tearing up the marshland buffers that helped dissipate tidal surges. Energy drilling removed vast quantities of subsurface liquid, which studies suggest increased the rate at which the land is sinking. Now Louisiana is losing approximately 25 square miles 65 square kilometers of wetlands every year, and the state is lobbying for federal money to help replace the upstream sediments that are the delta's lifeblood.
Local projects like that might not do much good in the very long run, though, depending on the course of change elsewhere on the planet.
Part of Antarctica's Larsen Ice Shelf broke apart in early Although floating ice does not change sea level when it melts any more than a glass of water will overflow when the ice cubes in it melt , scientists became concerned that the collapse could foreshadow the breakup of other ice shelves in Antarctica and allow increased glacial discharge into the sea from ice sheets on the continent. If the West Antarctic ice sheet were to break up, which scientists consider very unlikely this century, it alone contains enough ice to raise sea level by nearly 20 feet 6 meters.
Even without such a major event, the IPCC projected in its report that sea level will rise anywhere between 4 and 35 inches 10 and 89 centimeters by the end of the century. The high end of that projection—nearly three feet a meter —would be "an unmitigated disaster," according to Douglas. Down on the bayou, all of those predictions make Windell Curole shudder. Rising sea level is not the only change Earth's oceans are undergoing. The ten-year-long World Ocean Circulation Experiment , launched in , has helped researchers to better understand what is now called the ocean conveyor belt.
Oceans, in effect, mimic some functions of the human circulatory system. Just as arteries carry oxygenated blood from the heart to the extremities, and veins return blood to be replenished with oxygen, oceans provide life-sustaining circulation to the planet. Propelled mainly by prevailing winds and differences in water density, which changes with the temperature and salinity of the seawater, ocean currents are critical in cooling, warming, and watering the planet's terrestrial surfaces—and in transferring heat from the Equator to the Poles.
The engine running the conveyor belt is the density-driven thermohaline circulation "thermo" for heat and "haline" for salt. Warm, salty water flows from the tropical Atlantic north toward the Pole in surface currents like the Gulf Stream. This saline water loses heat to the air as it is carried to the far reaches of the North Atlantic. The coldness and high salinity together make the water more dense, and it sinks deep into the ocean. Surface water moves in to replace it. You will learn how glaciers interact with their immediate surroundings and how large ice bodies can act as an archive of past climate change.
We will use data from the Study Tour regions as case studies in the classroom as well as on the Study Tour. Research on ice cores, past climate change, volcanic deposits in ice, stable isotopes and stratigraphic dating of ice cores.
Participated in ice-core drillings in Greenland and Antarctica multiple times. With DIS since Participated in ice core drillings in Greenland and Antarctica since she was a grad student.