Group items tagged

Warming and Melting Mass loss from the ice sheets of Greenland and Antarctica account for a large fraction of global sea-level rise. Part of this loss is because of the effects of warmer air temperatures, and another because of the rising ocean temperatures to which they are being exposed. Joughin et al. (p. 1172) review how ocean-ice interactions are impacting ice sheets and discuss the possible ways that exposure of floating ice shelves and grounded ice margins are subject to the influences of warming ocean currents. Estimates of the mass balance of the ice sheets of Greenland and Antarctica have differed greatly-in some cases, not even agreeing about whether there is a net loss or a net gain-making it more difficult to project accurately future sea-level change. Shepherd et al. (p. 1183) combined data sets produced by satellite altimetry, interferometry, and gravimetry to construct a more robust ice-sheet mass balance for the period between 1992 and 2011. All major regions of the two ice sheets appear to be losing mass, except for East Antarctica. All told, mass loss from the polar ice sheets is contributing about 0.6 millimeters per year (roughly 20% of the total) to the current rate of global sea-level rise.

Hydronium/Hydroxide Balance When an acid dissolves in water, additional H3O+ is formed, increasing the concentration of H3O+. For example, the concentration of H3O+ might be increased from 10-7 M up to 10-5 M. That is 100 times more concentrated. Note that the pH, the number behind the negative sign in the exponent, changes from 7 to 5. This is why acidic solutions have pH values lower than 7.

"Scientific Workforce NSF Touts Family-Friendly Policies as Boon to Women 1. Jeffrey Mervis Young women are forever asking Meg Urry, an astrophysicist at Yale University, if it's possible "to have a successful scientific career and a family." A tenured professor with both, Urry tells them "yes." Perhaps more telling, however, is that the issue doesn't seem to interest half of her students. "I've never been asked that question by a man," she says. This week, the National Science Foundation (NSF) rolled out a set of family-friendly policies that it hopes will reduce the number of young women who jettison scientific careers because of responsibilities outside the lab. "Too many women give up because of conflicts between their desire to start a family and their desire to ramp up their careers," says John Holdren, the president's science adviser and head of the Office of Science and Technology Policy. It was a rare moment in the spotlight for the low-profile basic research agency: First Lady Michelle Obama announced the policies at a White House ceremony touting the importance of women to the nation's economic recovery and, in particular, the need to improve the proportion of women in the so-called STEM (science, technology, engineering, and mathematics) workforce. Figure View larger version: * In this page * In a new window Lending a hand. First Lady Michelle Obama applauds the work of young women in science at a White House event. "CREDIT: NATIONAL SCIENCE FOUNDATION" The new policies will allow both male and female grant recipients to defer an award for up to 1 year or receive a no-cost extension of an existing grant. NSF also hopes to increase its use of "virtual reviews" of grant proposals so that scientists don't need to travel as often to the agency's Arlington, Virginia, headquarters. The only change with any price tag attached is a new program of supplemental awards to investigators going on family leave, allowing them to hi

Aerosols Altered Asian Monsoons Summer monsoons provide much of the water for farming on the Indian subcontinent, but the pattern of rain shifted dramatically during the last half of the 20th century. In a study appearing online 29 September in Science, researchers pin the blame on soot and other aerosols from human activities. From 1951 to 1999, central-northern India became drier while Pakistan, northwestern India, and southern India got wetter. To determine whether these changes were due to natural variability or human interference (greenhouse gases or aerosols), climate scientists Massimo Bollasina, Yi Ming, and V. Ramaswamy of the Geophysical Fluid Dynamics Laboratory/NOAA in Princeton, New Jersey, compared the history of rainfall with simulations that singled out each climate "forcing" factor to observe its impact. Although greenhouse gases would have increased rainfall over north-central India, the aerosols, they found, caused the "very pronounced drying trend," Ming says. Here's why: Under normal conditions, the northern hemisphere receives more energy from the sun from June to September; that imbalance drives the ocean-atmosphere circulation that powers the monsoons. But atmospheric aerosols shaded the northern hemisphere relative to the southern hemisphere, altering the energy balance between the two-weakening the circulation and altering where the rain falls.