"On 30 August we first noted evidence that walruses were being forced ashore as sea-ice disappeared..."
"Arctic sea ice continued to decline and by Friday 3 September had dropped to the third lowest extent on record...as the USGS reported that thousands of walruses were hauling out on the Alaska shore..."
"As sea ice has receded over the last decade, young walruses are increasingly separated from their mothers, drifting in the open-sea."
"We were on a station for 24 hours, and the calves would be swimming around us crying. We couldn’t rescue them,' said Carin Ashjian, a biologist at Woods Hole Oceanographic Institution and a member of the research team....`If walruses and other ice-associated marine mammals cannot adapt to caring for their young in shallow waters without sea-ice available as a resting platform between dives to the sea floor, a significant population decline of this species could occur,' the research team wrote."
"The decision by the U.S. EPA to transition from an O3 standard based upon a 1-hour average to a standard based upon an 8-hour average was prompted by research indicating that prolonged exposure to O3 at concentrations lower than the 1-hour standard can have significant impacts upon human health. There is also research indicating that prolonged exposure to O3 is particularly harmful to vegetation."
"Clear evidence shows that ozone damages economically, ecologically, and aesthetically important plants. When exposed to ozone, major annual crops produce reduced yields. Some tree species suffer injury to needles or leaves, lowered productivity, and in severe cases, INDIVIDUAL TREES CAN DIE. Important tree species are seriously affected in large areas of the country. In the most heavily affected forested areas, such as the San Bernardino National Forest in California, ozone has begun altering the natural ecological balance of species.""Excessive ozone and precursor pollutant transport affect more than just cities and suburbs. Both crops and trees in rural areas are sensitive to zone concentrations well below the human health-based standard."Light flecks, dark stipples, yellow spots, premature aging, and leaf loss mark annual crops injured by ozone; reduced growth rates and yields may occur even without visible injury. Crop losses increase as ozone concentrations rise. At concentrations found in rural areas throughout much of the United Sates, ozone depresses yields of economically important crops such as soybeans and cotton by between a few and 20 percent...""Ozone-induced injury in trees shows up primarily as foliar injury, including leaf or needle discoloration and premature loss. In advanced cases, needles or leaves and then branches die back...Reduced growth rates may precede or follow foliar injury. Increased susceptibility to diseases and other stresses may result from reduced photosynthesis and decreased allocation of carbohydrates to tree roots. Ultimately trees may die prematurely."
"The U.S. Environmental Protection Agency (EPA) presently uses a 40 ppbv background 03 level as a baseline in its 03 risk assessments. This background is def'med as those concentrations that would exist in the absence of North American emissions. Lefohn et al.  have argued that frequent occurrences of 03 concentrations above 50-60 ppbv at remote northern U.S. sites in spring are of stratospheric origin, challenging the EPA background estimate and implying that the current 03 standard (84 ppbv, 8-hour average) may be unattainable. We show that a 3-D global model of tropospheric chemistry reproduces much of the observed variability in U.S. surface 03 concentrations, including the springtime high-O3 events, with only a minor stratospheric contribution (always <> 2 km). It declines from spring to summer and further decreases during 03 pollution episodes. The 40 ppbv background assumed by EPA thus actually underestimates the risk associated with 03 during polluted conditions. A better definition would represent background as a function of season, altitude, and total surface 03 concentration. Natural 03 levels are typically 10-25 ppbv and never exceed 40 ppbv. International controls to reduce the hemispheric pollution background would facilitate compliance with an AOT40-type standard."