Research May Also Help Determine Effects of Global Warming in the Region
With more than 40 million people living under exceptional drought conditions in East Africa, the ability to make accurate predictions of drought has never been more important. In the aftermath of widespread famine and a humanitarian crisis caused by the 2010-2011 drought in the Horn of Africa—possibly the worst drought in 60 years— researchers are striving to determine whether drying trends will continue.
While it is clear that El Niño can affect precipitation in this region of East Africa, very little is known about the drivers of long-term shifts in rainfall. However, new research described in the journal Nature helps explain the mechanisms at work behind historical patterns of aridity in Eastern Africa over many decades, and the findings may help improve future predictions of drought and food security in the region. (more…)
Computer Models, Satellite Data Reveal Clearest Evidence Yet of Human Influence on Changing Temperatures
New research shows some of the clearest evidence yet of a discernible human influence on atmospheric temperature.
Published online in the Nov. 29 early edition of the Proceedings of the U.S. National Academy of Sciences, the study compared 20 of the latest climate models against 33 years of satellite data. When human factors were included in the models, they followed the pattern of temperature changes observed by satellite. When the same simulations were run without considering human influences, the results were quite different.
“We can only match the satellite record when we add in human influences on the atmosphere,” said Michael Wehner, a research scientist at Lawrence Berkeley National Laboratory (Berkeley Lab) Computational Research Division and a coauthor of the article, which involved colleagues from 16 other organizations and was led by Benjamin Santer, an atmospheric scientist at Lawrence Livermore National Laboratory (LLNL). (more…)
There’s an old adage (with several variations) that California has four seasons: earthquake, fire, flood and drought. While Californians happily cede the title of Hurricane Capital of America to U.S. East and Gulf coasters, every once in a while, Mother Nature sends a reminder to Southern Californians that they are not completely immune to the whims of tropical cyclones. Typically, this takes the form of rainfall from the remnants of a tropical cyclone in the eastern Pacific, as happened recently when the remnants of Hurricane John brought rain and thunderstorms to parts of Southern California. But could a hurricane ever make landfall in Southern California?
The answer, as it turns out, is yes, and no. While there has never been a documented case of a hurricane making landfall in California, the Golden State has had its share of run-ins and close calls with tropical cyclones. In fact, California has been affected by at least a few tropical cyclones in every decade since 1900. Over that timeframe, three of those storms brought gale-force winds to California: an unnamed California tropical storm in 1939, Kathleen in 1976 and Nora in 1997. But the primary threat from California tropical cyclones isn’t winds or storm surge. It’s rainfall — sometimes torrential — which has led to flooding, damage and, occasionally, casualties. (more…)
COLLEGE PARK, Md. –– A University of Maryland scientist and an undergraduate Indian student he mentored in India have uncovered a major new finding about El Nino — the cyclical climate event that appears every 2-7 years, sometimes with major global weather impacts such as massive flooding in some regions and severe droughts in others and resulting major economic impacts.
Just published in Nature Climate Change, their research reveals a previously unrecognized sign of a looming El Nino that can be detected up to 18 months in advance, nine months earlier than current forecasting models allow. Raghu Murtugudde, a UMD professor of atmospheric and oceanic science, and Nandini Ramesh, who was an undergraduate student at the Divecha Centre for Climate Change, Indian Institute of Science in Bangalore India when this research was performed, say their new clue to the beginning of an El Nino lies in the discharge of massive volumes of sub-surface warm water from the equatorial western Pacific Ocean north of Australia. (more…)
ANN ARBOR, Mich.—It’s a message no one wants to hear: To slow down global warming, we’ll either have to put the brakes on economic growth or transform the way the world’s economies work.
That’s the implication of an innovative University of Michigan study examining the evolution of atmospheric CO₂, the most likely cause of global warming.
The study, conducted by José Tapia Granados and Edward Ionides of U-M and Óscar Carpintero of the University of Valladolid in Spain, was published online in the peer-reviewed journal Environmental Science and Policy. It is the first analysis to use measurable levels of atmospheric carbon dioxide to assess fluctuations in the gas, rather than estimates of CO₂ emissions, which are less accurate. (more…)
La Niña, “the diva of drought,” is peaking, increasing the odds that the Pacific Northwest will have more stormy weather this winter and spring, while the southwestern and southern United States will be dry.
Sea surface height data from NASA’s Jason-1 and -2 satellites show that the milder repeat of last year’s strong La Niña has recently intensified, as seen in the latest Jason-2 image of the Pacific Ocean, available at: https://sealevel.jpl.nasa.gov/images/ostm/20120108P1.jpg.(more…)
*Computer simulations of global climate lead to new conclusions*
Earth’s deep oceans may absorb enough heat at times to flatten the rate of global warming for periods of as long as a decade–even in the midst of longer-term warming. This according to a new analysis led by scientists at the National Center for Atmospheric Research (NCAR).
The study, based on computer simulations of global climate, points to ocean layers deeper than 1,000 feet as the main location of the “missing heat” during periods such as the past decade when global air temperatures showed little trend. (more…)
Is it possible to make valid climate predictions that go beyond weeks, months, even a year? UCLA atmospheric scientists report they have now made long-term climate forecasts that are among the best ever — predicting climate up to 16 months in advance, nearly twice the length of time previously achieved by climate scientists.
Forecasts of climate are much more general than short-term weather forecasts; they do not predict precise temperatures in specific cities, but they still may have major implications for agriculture, industry and the economy, said Michael Ghil, a distinguished professor of climate dynamics in the UCLA Department of Atmospheric and Oceanic Sciences and senior author of the research. (more…)