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Rising temperature difference between hemispheres could dramatically shift rainfall patterns in tropics. One often ignored consequence of global climate change is that the Northern Hemisphere is becoming warmer than the Southern Hemisphere, which could significantly alter tropical precipitation patterns, according to a new study by climatologists from the University of California, Berkeley, and the University of Washington, Seattle. Such a shift could increase or decrease seasonal rainfall in areas such as the Amazon, sub-Saharan Africa or East Asia, leaving some areas wetter and some drier than today. "A key finding is a tendency to shift tropical rainfall northward, which could mean increases in monsoon weather systems in Asia or shifts of the wet season from south to north in Africa and South America," said UC Berkeley graduate student Andrew R.

Friedman, who led the analysis. "Tropical rainfall likes the warmer hemisphere," summed up John Chiang, UC Berkeley associate professor of geography and a member of the Berkeley Atmospheric Sciences Center. 20th century rainfall patterns. Genghis Khan's Secret Weapon Was Rain. For unsuspecting herdsmen in the 13th century, April showers didn't bring May flowers—they brought Mongol hordes. New research by tree-ring scientists from Columbia University's Lamont-Doherty Earth Observatory and West Virginia University may have uncovered the reason why an obscure band of nomadic Mongol horsemen were able to sweep through much of Asia in a few meteoric decades 800 years ago, conquering everything in their path: They enjoyed an unprecedented, and yet-to-be-repeated, 15-year run of bountiful rains and mild weather on the normally cold and arid steppes.

By sampling tree rings in the gnarled and twisted Siberian pines in the Hangay Mountains in central Mongolia, the team pieced together a remarkably precise chronology of local climatic conditions stretching from the year 900 A.D. to the present. The study, published in this week's Proceedings of the National Academy of Sciences, offers a new interpretation of why the Mongols suddenly went on the move. And ride it he did. Elevated carbon dioxide making arid regions greener. Scientists have long suspected that a flourishing of green foliage around the globe, observed since the early 1980s in satellite data, springs at least in part from the increasing concentration of carbon dioxide in Earth's atmosphere.

Now, a study of arid regions around the globe finds that a carbon dioxide "fertilization effect" has, indeed, caused a gradual greening from 1982 to 2010. Focusing on the southwestern corner of North America, Australia's outback, the Middle East, and some parts of Africa, Randall Donohue of the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Canberra, Australia and his colleagues developed and applied a mathematical model to predict the extent of the carbon-dioxide (CO2) fertilization effect. They then tested this prediction by studying satellite imagery and teasing out the influence of carbon dioxide on greening from other factors such as precipitation, air temperature, the amount of light, and land-use changes. Attenborough Explains Easter Island. Greenhouse_2011. Interactive 3.

Analyzing an Ecosystem. Global Warming Simulation, Global Warming Interactive, Climate Change Interactive. First Mammal Species Goes Extinct Due to Climate Change The humble Bramble Cay melomys has disappeared from its island in the Great Barrier Reef. Climate Change Making Calendars Run Amok People in Central Asia are recalibrating their system of time to adapt to a changing ecosystem.

The Great Energy Challenge The National Geographic initiative is a call to action to become actively involved, to learn more and do more—to change how we think about and consume energy so that we can all help tackle the big energy questions. U.S.'s First Official Climate Refugees Race Against Time A Native American tribe struggles to hold on to their culture while their land slips into the Gulf of Mexico. Crocodiles and Palm Trees in the Arctic?

If we keep burning fossil fuels, Earth will return to the climate of 52 million years ago, according to new research. The Arctic Is Melting. Future Climate Change | Climate Change. Key Points Continued emissions of greenhouse gases will lead to further climate changes. Future changes are expected to include a warmer atmosphere, a warmer and more acidic ocean, higher sea levels, and larger changes in precipitation patterns. The extent of future climate change depends on what we do now to reduce greenhouse gas emissions. The more we emit, the larger future changes will be. Increasing greenhouse gas concentrations will have many effects Greenhouse gas concentrations in the atmosphere will continue to increase unless the billions of tons of our annual emissions decrease substantially. Increased concentrations are expected to: Increase Earth's average temperature Influence the patterns and amounts of precipitation Reduce ice and snow cover, as well as permafrost Raise sea level Increase the acidity of the oceans These changes will impact our food supply, water resources, infrastructure, ecosystems, and even our own health .

Future changes will depend on many factors. Climate Time Machine.