Why Is It Important?


The simulations all agreed that continued global warming will lead to increases in storm days over large areas of the eastern United States in the spring, winter, and autumn.


The changes mean that for springtime alone, severe thunderstorms could increase by as much as 40 percent over the eastern U.S. by the end of the century, Diffenbaugh said.


What Does This Mean?


Severe thunderstorms, which are often associated with heavy rainfall, hail, and even tornadoes, are one of the primary causes of major economic losses in the United States.


In 2012, seven of the country's $11 billion weather disasters were caused by severe thunderstorms and tornadoes.


"Sadly, we have many examples of cases where a single storm has had disastrous impact," Diffenbaugh said in a statement. "So a 25 or 30 percent increase in the annual occurrence represents a substantial increase in the overall risk."

The new research shows that acidification in surface waters of the Arctic Ocean is rapidly expanding into areas that were previously isolated from contact with the atmosphere due to the former widespread ice cover.

"A remarkable 20 percent of the Canadian Basin has become more corrosive to carbonate minerals in an unprecedented short period of time. Nowhere on Earth have we documented such large scale, rapid ocean acidification" according to lead researcher and ocean acidification project chief, U.S. Geological Survey oceanographer Lisa Robbins.

The authors attribute warming from 1900-1939 to rapidly rising black carbon emissions, diminishing influence of the Santa Maria volcanic eruption in 1902, and warming North Atlantic sea surface temperatures. Cooling from 1939 to 1970 is attributed to cooling from anthropogenic sulfate aerosol emissions the Agung volcanic eruption in 1963, and falling North Atlantic surface temperatures.
More recently, the authors attribute warming from 1970 to present to increased anthropogenic greenhouse gas emissions, with a smaller contribution from warming North Atlantic sea surface temperatures.

In a paper published in the journal Science on Sept. 13, the team describes how at one of their study sites, halfway down the ice shelf, the melt rate was as high as 2.36 inches (6 centimeters) per day.

Speaking today at the Living Planet Symposium in Edinburgh, UK, Prof. Andrew Shepherd from the University of Leeds, UK, said, �CryoSat continues to provide clear evidence of diminishing Arctic sea ice.

�From the satellite�s measurements we can see that some parts of the ice pack ice have thinned more rapidly than others, but there has been a decrease in the volume of winter and summer ice over the past three years.

The researchers exposed one species of coccolithophores (Emiliania huxleyi) to the temperatures and acidic conditions that are expected to be common in the Earth�s oceans in 100 years. The one year experiment produced 700 generations of the algae.

Unexpectedly, the algae were able to maintain the growth of their calcified shells and continue to incorporate atmospheric carbon into those shells. Similar experiments found the same species of algae grew calcified shells at a lower rate in cold water with high acidity.

...........

This work is the first indication that natural algal adaptations may moderate some of the anticipated effects of climate change.

Polar oceans are chemically sensitive to anthropogenic acidification due to their relatively low alkalinity and correspondingly weak carbonate buffering capacity. Here, we compare unique CO2 system observations covering complete annual cycles at an Arctic (Amundsen Gulf) and Antarctic site (Prydz Bay). The Arctic site experiences greater seasonal warming (10 vs 3�C), and freshening (3 vs 2), has lower alkalinity (2220 vs 2320??mol/kg), and lower summer pH (8.15 vs 8.5), than the Antarctic site. Despite a larger uptake of inorganic carbon by summer photosynthesis, the Arctic carbon system exhibits smaller seasonal changes than the more alkaline Antarctic system. In addition, the excess surface nutrients in the Antarctic may allow mitigation of acidification, via CO2 removal by enhanced summer production driven by iron inputs from glacial and sea-ice melting. These differences suggest that the Arctic system is more vulnerable to anthropogenic change due to lower alkalinity, enhanced warming, and nutrient limitation.

Three atmospheric patterns came together above the Indian and Pacific Oceans in 2010 and 2011. When they did, they drove so much precipitation over Australia that the world's ocean levels dropped measurably.

Unlike other continents, the soils and topography of Australia prevent almost all its precipitation from flowing into the ocean.

The 2010-11 event temporarily halted a long-term trend of rising sea levels caused by higher temperatures and melting ice sheets, according to a team of researchers at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., and other institutions.

Now that the atmosphere's circulation has returned to its previous patterns, the seas are again rising.

..."Error has occurred - check the event log for details".