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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.
Featured on USGS, a member of the U.S. Global Change Research Program
Recording how climatic variations and trends impact seasonal events in plants.
Credit: A. Miller-Rushing
As the climate has warmed, many plants are starting to grow leaves and bloom flowers earlier. A new study published in the journal, Nature, suggests that most field experiments may underestimate the degree to which the timing of leafing and flowering changes with global warming.
Understanding how plants are responding to climate change will help develop more accurate indicators of spring, forecast the onset of allergy season or the chances of western wildfires, manage wildlife and invasive plants, and help inform habitat restoration plans. In this new study, scientists evaluated the sensitivity of plants to changes in temperature using two sources: experimental plots versus historical observations from natural sites. Read more…
Featured on USDA, a member of the U.S. Global Change Research Program
A recent study by the USDA Forest Service, Oregon State University, and the U.S. Geological Survey identified trends in stream temperatures at sites like Mack Creek near the H.J. Andrews Experimental Forest in Oregon.
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Recent warming of terrestrial climates combined with decreased stream flows has raised concerns about possible increases in stream temperatures in the Pacific continental United States. Loss of cold, clean water in the region has major implications for human use and for sensitive coldwater fishes, such as salmon and trout. In a joint project, the U.S. Geological Survey (USGS), U.S. Forest Service’s Pacific Northwest Research (PNW) Station, and Oregon State University (OSU) researchers assessed the climate effects on cold water in low and high human-influenced sites using long-term stream temperature data from the USGS and the Forest Service….
A new study by scientists at Stanford and Purdue University projects that corn prices in the United States will become much more volatile in the near term because of more frequent severe heat conditions expected to result from human-caused climate change. The study also concludes that corn price volatility is more sensitive to near-term climate change than other commonly-cited factors such as energy markets or policy choices. Volatility in price for commodities like corn can translate to fluctuating prices on store shelves.
American corn farmers know from experience that weather events like flooding, drought, or extreme heat can cause crop yields to vary from year to year and affect the price of products containing corn for consumers. At the same time, policies that set minimum levels of corn-based biofuels for the national fuel supply also impact prices because they create additional demand for corn. But science also tells us that climate change is upping the odds for more frequent and extreme weather events in many regions of the United States – adding another layer of complexity to the corn-price equation.
The new study, published in the journal Nature Climate, integrates historical data from each of these areas—agriculture, energy, economics, and weather—with models of future markets and climate scenarios to determine the effect of climate-change-induced heat extremes on price volatility for corn. The authors conclude that climate change impacts pose a particular risk for corn crops—which are by nature very heat-sensitive—and that prices will swing much more wildly from year to year as a result of climate change than as a result of other forcing factors—even assuming relatively modest levels of global warming over the next few decades. The authors also find that policies requiring the use of corn for the production of biofuels can further amplify price volatility. In years when corn yields are already low, for example, such policies further diminish the amount of corn that can be directed toward consumers, thus driving up prices.
The study highlights the close relationship between American agriculture and climate change—a link that has been investigated in other scientific documents such as the U.S. Global Change Research Program’s 2009 report Global Climate Change Impacts in the United States, which warns that climate-change-related heavy downpours and droughts are likely to reduce crop yields. The study also concludes that while some crops show positive responses to small increases in atmospheric carbon dioxide (CO2) and temperature, large increases often negatively affect growth and yields.
“Corn grows in almost every state and is very responsive to changes in climate,†said Jerry Hatfield, Director of the U.S. Department of Agriculture (USDA) National Laboratory for Agriculture and the Environment, in a recent statement. “As the temperature gets warmer, corn reproduction and grain development are going to be decreased, everything else equal.â€
Exposure to extreme temperature events during the critical pollination phase can be particularly detrimental to corn yields because pollen doesn’t survive well in extremely hot conditions. Temperatures above 95◦F, for example, will reduce the number of pollen grains that are able to complete fertilization, decreasing the number of kernels per ear of corn. Some producers are already taking steps to cope with these impacts, such as planting crops earlier to avoid having pollination occur on the hottest days, or switching to different crops altogether.
The new study on price volatility is an important reminder that as the frequency and severity of extreme weather events increases due to climate change, farmers may feel the effects on the ground, and citizens may feel them in their wallets.
Featured on USGS, a member of the U.S. Global Change Research Program
Data collected from long distance swims by Polar bears suggest that they do not stop to rest during their journey.
“Polar bears spend much of their lives in and around water, and they are well adapted for swimming. But recent findings of USGS scientists demonstrate that they are even better swimmers than many imagined: In years of extreme sea-ice retreat in the southern Beaufort Sea region of Alaska, polar bears have been documented taking very long swims, in excess of 30 miles.
Data collected from long distance swims by Polar bears suggest that they do not stop to rest during their journey. In addition to being an impressive feat, this provides some tantalizing clues into the polar bear’s future in an Arctic with less sea ice. That these bears can swim such long distances might mean that they are not as vulnerable to being stranded at sea as has been depicted by the media. Scientists wonder, however, if polar bears might be expending essential energy in swimming long distances.â€
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