Changes In Extreme Temperature and Precipitation in the Arab Region

by Tim Storer

Extreme weather events have major impacts on societies around the globe, and it is beneficial to have detailed climate data that show trends in extreme temperatures and precipitation. There are currently many areas with inadequate past research, such as the Arab regions in Northern Africa and the Arabian Peninsula. In order to help fill this gap, a meeting of several different climate research organizations was held so that data from all the necessary countries could be compiled. Many parts of the dry Arab region are particularly vulnerable to flooding in the case of extreme rain fall, making this an important area of study. Unlike past studies, this research did not collect data from within specific political borders, but grouped areas together based on similar climate characteristics. There were observed trends in overall warming throughout the region, as well as relationships between local temperature and multi-year climate cycles such as El Niño Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) (Donat et al. 2013). Continue reading

Comets, Climate Change, and Extinctions—1

by Emil Morhardt

At the end of the last ice age as the Earth was warming to its present condition there was an unexplained 1000-year pause and partial reversal in the warming (called the Younger-Dryas stadial). The result was a millennium of very cold weather in the Northern Hemisphere. The cause was widely attributed to the abrupt stoppage of the Gulf Stream; warm water was no longer transported from the equator north past the US east coast and Europe toward Greenland. The physical cause of the stoppage was presumably the melting of the Laurentide Ice Sheet covering Canada; enough freshwater flowed out over the North Atlantic near Greenland, that it formed a thick layer on top of the ocean that was not dense enough to sink through the underlying salt water. It is sinking saltwater off Greenland that drives the major global ocean currents—the Meridional Overturning Circulation (MOC)—of which the Gulf Stream is the last leg. Scientists are somewhat worried that under the current warming conditions, enough meltwater could flow off the Greenland Ice sheet to wreak the same sort of havoc…a much colder North America and Europe in the midst of a generally warming globe. In 2007, Firestone et al. presented an unexpected theory that the trigger for the freshwater outflow 12,900 years ago was an extraterrestrial (ET) impact event—a comet or meteorite—that also directly led to the Continue reading