Featured on USGS, a member of the U.S. Global Change Research Program
â€œRates of sea level rise are increasing three-to-four times faster along portions of the U.S. Atlantic Coast than globally, according to a new U.S. Geological Survey report published in Nature Climate Change. Since about 1990, sea-level rise in the 600-mile stretch of coastal zone from Cape Hatteras, N.C. to north of Boston, Mass. -- coined a "hotspot" by scientists -- has increased 2 - 3.7 millimeters per year; the global increase over the same period was 0.6 â€“ 1.0 millimeter per year.
Based on data and analyses included in the report, if global temperatures continue to rise, rates of sea level rise in this area are expected to continue increasing. The report shows that the sea-level rise hotspot is consistent with the slowing of Atlantic Ocean circulation. Models show this change in circulation may be tied to changes in water temperature, salinity and density in the subpolar north Atlantic.â€ Read More
A series of studies by the U.S. Department of Agriculture (USDA) and academic institutions offers accumulating evidence that climate change is both lengthening and intensifying pollen seasons in many parts of the United States.
Carbon dioxide (CO2) in the atmosphere directly affects plants by supplying the carbon they need for photosynthesis. In some cases, elevated CO2 Âlevels can help plants grow fasterâ€”a potential boon when that plant is an agriculturally important species.
But as USDA and other scientists pointed out in a 2009 Environmental Health Perspectives (EHP) study, CO2 â€œdoes not discriminateâ€ between desirable and undesirable plants. That means that while there may be benefits to faster-growing species like forest trees, for example, there can be serious negative consequences when these growth spurts occur Â in other plants, like ragweedâ€”a plant to which at least ten percent of the U.S. population is sensitive.
Some studies suggest that carbon-induced growth increases may be especially great in some pest plant species. The U.S. Global Change Research Program cited in its most recent National Climate Assessment, for example, that when exposed to the same heightened CO2 levels, poison ivy growth increases are nearly five times those in tree species.
Itâ€™s also been shown that higher atmospheric CO2 Âlevels as well as warmer temperaturesâ€” two key aspects of climate changeâ€”may be contributing to the intensification of pollen seasons. A recent field study, for example, found that both factors â€œsignificantly influenceâ€ pollen production in common ragweed and can increase pollen concentrations in the atmosphere.
Other science tells us that some plant species are not only producing more pollen, but are also doing so over longer periods of timeâ€”an effect thatâ€™s already being seen on the ground. In a recent study published in the Proceedings of the National Academy of Sciences, USDA researchers and others found that in parts of North America, the ragweed pollen season is up to three weeks longer than it was in the mid-1990â€™s because of climate change.
â€œThis finding is just one demonstration that plants respond to climate change in ways that are likely to affect people,â€ said Dr. Lewis Ziska, a scientist at USDAâ€™s Agricultural Research Service (ARS) and author of the PNAS study. Â
â€œWe study these aspects of plant responseâ€”from weeds, to wheat, to cellulosic biofuelsâ€”so that growers can continue to effectively provide our supply of food, feed, fiber and fuel, and so that citizens and health professionals can predict and deal with health impacts in the face of climatic uncertainty.â€
While the magnitude of climate-change impact on allergic disease is not yet known, the Centers for Disease Control and Prevention, and other research institutions suggest that there could be a â€œsubstantial effect.â€
â€œThese documented increases in pollen exposures are one of the clearest examples of how a changing climate is already affecting the health of people in the United States," said Dr. John Balbus, Senior Advisor for Public Health at the National Institute of Environmental Health Sciences, adding that other climate-induced ecosystem changes could result in additional health challenges.
"Just as trees and weeds respond to a changing climate, so too do ticks, mosquitoes, and other carriers of human diseases, making it critical that we anticipate all these changing patterns of disease and protect those most vulnerable."
Today, allergic disorders, including asthma, comprise the 6th leading cause of chronic illness in the Nation. They affect more than 50 million Americans per year and cost the United States nearly $20 billion annually. Given the number of studies documenting and projecting longer and more intense pollen seasons as a result of increasing temperatures and CO2 levels, we can expect those impacts and costs to grow even larger if the Nation and the world do not address climate change aggressively.
Featured by NOAA.gov, a member of the U.S. Global Change Research Program
The national temperature of 57.1 degrees F during spring was 5.2 degrees F above the long-term average, besting the previous warmest spring of 1910 by 2.0 degrees F. This marked the largest temperature departure from average of any season on record for the contiguous United States. The spring of 2012 was the culmination of the warmest March, third warmest April, and second warmest May. This marks the first time that all three months during the spring season ranked among the ten warmest, since records began in 1895.
Featured by NOAA, a member of the U.S. Global Change Research Program
At NOAA's atmospheric baseline observatory in Barrow, Alaska, captured here by fisheye lens, the concentration of the greenhouse gas carbon dioxide reached 400 ppm in April 2012, the first time a monitoring sites reached the 400 mark. Carbon dioxide levels are steadily increasing in the atmosphere due to human activities, primarily the burning of fossil fuels. Image credit: NOAA
The concentration of carbon dioxide in the atmosphere of Barrow, Alaska, reached 400 parts per million (ppm) this spring, according to NOAA measurements, the first time a monthly average measurement for the greenhouse gas attained the 400 ppm mark in a remote location.
Carbon dioxide (CO2), emitted by fossil fuel combustion and other human activities, is the most significant greenhouse gas contributing to climate change.
â€œThe northern sites in our monitoring network tell us what is coming soon to the globe as a whole,â€ said Pieter Tans, an atmospheric scientist with NOAAâ€™s Earth System Research Laboratory (ESRL) in Boulder, Colo. â€œWe will likely see global average CO2 concentrations reach 400 ppm about 2016.â€ Read moreâ€¦
Featured by USGS, a member of the U.S. Global Change Research Program
The low streamflows seen throughout much of New England this April do not foreshadow a summer drought, as researchers have determined summer rainfall plays a bigger role than snowmelt runoff in determining streamflows in the summer. In a new report by the U.S. Geological Survey, scientists also looked at how streamflow during April is influenced by both winter air temperature and precipitation. They concluded that April streamflow is more sensitive to changes in temperature than to changes in winter precipitation in southern New England.
While streamflow in April is more sensitive to changes in temperature, summer streamflows are more dependent on precipitation. Understanding the sensitivity of streamflow to climatic variation is important because people and aquatic ecosystems are dependent upon water supplies, particularly in summer low-flow seasons. Read more.