By combining a hurricane model and coupled ocean-atmosphere general circulation model to investigate the early Pliocene, Emanuel, Brierley and co-author Alexey Fedorov observed how vertical ocean mixing by hurricanes near the equator caused shallow parcels of water to heat up and later resurface in the eastern equatorial Pacific as part of the ocean wind-driven circulation. The researchers conclude from this pattern that frequent hurricanes in the central Pacific likely strengthened the warm pool in the eastern equatorial Pacific, which in turn increased hurricane frequency — an interaction described by Emanuel as a “two-way feedback process.”�The researchers believe that in addition to creating more hurricanes, the intense hurricane activity likely created a permanent El Nino like state in which very warm water in the eastern Pacific near the equator extended to higher latitudes. The El Nino weather pattern, which is caused when warm water replaces cold water in the Pacific, can impact the global climate by intermittently altering atmospheric circulation, temperature and precipitation patterns.The research suggests that Earth’s climate system may have at least two states — the one we currently live in that has relatively few tropical cyclones and relatively cold water, including in the eastern part of the Pacific, and the one during the Pliocene that featured warm sea surface temperatures, permanent El Nino conditions and high tropical cyclone activity.Although the paper does not suggest a direct link with current climate models, Fedorov said it is possible that future global warming could cause Earth to transition into a different equilibrium state that has more hurricanes and permanent El Nino conditions. “So far, there is no evidence in our simulations that this transition is going to occur at least in the next century. However, it’s still possible that the condition can occur in the future.”�Whether our future world is characterized by a mean state that is more El Nino-like remains one of the most important unanswered questions in climate dynamics, according to Matt Huber, a professor in Purdue University’s Department of Earth and Atmospheric Sciences. The Pliocene was a warmer time than now with high carbon dioxide levels. The present study found that hurricanes influenced by weakened atmospheric circulation — possibly related to high levels of carbon dioxide — contributed to very warm temperatures in the Pacific Ocean, which in turn led to more frequent and intense hurricanes. The research indicates that Earth’s climate may have multiple states based on this feedback cycle, meaning that the climate could change qualitatively in response to the effects of global warming.
thinkahol * on 23 Oct 11By now, you probably think your opinion of Goldman Sachs and its swarm of Wall Street allies has rock-bottomed at raw loathing. You're wrong. There's more. It turns out that the most destructive of all their recent acts has barely been discussed at all. Here's the rest. This is the story of how some of the richest people in the world - Goldman, Deutsche Bank, the traders at Merrill Lynch, and more - have caused the starvation of some of the poorest people in the world. It starts with an apparent mystery. At the end of 2006, food prices across the world started to rise, suddenly and stratospherically. Within a year, the price of wheat had shot up by 80 per cent, maize by 90 per cent, rice by 320 per cent. In a global jolt of hunger, 200 million people - mostly children - couldn't afford to get food any more, and sank into malnutrition or starvation. There were riots in more than 30 countries, and at least one government was violently overthrown. Then, in spring 2008, prices just as mysteriously fell back to their previous level. Jean Ziegler, the UN Special Rapporteur on the Right to Food, calls it "a silent mass murder", entirely due to "man-made actions."
