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"The theme of the 175th Annual Meeting of the American Association for the Advancement of Science (AAAS), "Our Planet and Its Life, Origins, and Futures," celebrated an enormous breadth of scientific accomplishments that transcends many subdisciplines of the natural and social sciences. It was intended to be both a reflection on what has been learned and a look forward to what must yet be better known if we are to make wise choices as stewards of our planet. The program committee saw this as an opportunity to examine how we have come to know and understand the coevolution of life with its interacting biological, biogeochemical, and physical environments. Further advances in this area are essential to develop scenarios that can be useful in guiding decisions to address some of society's most pressing problems. We must work toward a future that embraces the wise application of science to improve human health and well-being and to sustain the great diversity of life on our planet. "

Table of Contents About Science for All Americans and Atlas of Science Literacy.................................................. 4 From Chapter 1: The Nature of Science ............................... 5 From Chapter 3: The Nature of Technology ......................... 7 Map: Scientifi c Investigations ............................................. 11 Map: Interaction of Technology and Society ..................... 13 Map: Decisions about Using Technology ........................... 15 From Chapter 4: The Physical Setting ............................... 16 Recommended Reading ..................................................... 17 Map: Weather and Climate .................................................. 19 Map: Use of Earth's Resources ............................................ 21 From Chapter 8: The Designed World ................................ 22 From Chapter 5: The Living Environment .......................... 23 Map: Energy Resources ...................................................... 25 Map: Interdependence of Life ............................................ 27 Recommended Reading ..................................................... 28 Web Sites for Climate Change Resources ........................... 29

Experts Agree Global Warming Is Melting the World Rapidly Richard A. Kerr Forty-seven glaciologists have arrived at a community consensus over all the data on what the past century's warming has done to the great ice sheets: a current annual loss of 344 billion tons of glacial ice, accounting for 20% of current sea level rise. Greenland's share-about 263 billion tons-is roughly what most researchers expected, but Antarctica's represents the first agreement on a rate that had ranged from a far larger loss to an actual gain. The new analysis, published on page 1183 of this week's issue of Science, also makes it clear that losses from Greenland and West Antarctica have been accelerating, showing that some ice sheets are disconcertingly sensitive to warming.

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.