hypercane

IPS Direct to Your Inbox! Global Affairs Africa Asia-Pacific Afghanistan Iran Caribbean Haiti Europe Union in Diversity Latin America Mideast & Mediterranean Iraq Israel/Palestine North America Neo-Cons Bush at War Development MDGs City Voices Corruption Civil Society Globalisation Environment Energy Crunch Climate Change Tierramérica Human Rights Health HIV/AIDS Indigenous Peoples Economy & Trade Labour Population Reproductive Rights Migration&Refugees Arts & Entertainment Education ExPress Freedom Columns In Focus Readers' Opinions Email News BROOKLIN, Canada, Sep 16 (IPS) - The number of super-powerful storms like Hurricane Katrina has nearly doubled and there will be even more in the future as the world's oceans continue to warm, scientists say. Climate change is warming the surface of the oceans, and the additional heat provides the extra energy to generate more powerful hurricanes and cyclones. The number of Category 4 and 5 hurricanes worldwide has nearly doubled over the past 35 years, according to a new study published Friday in the journal Science. "Warmer sea surface temperatures have increased the amount of water vapour, which is the fuel for hurricanes," said study co-author Peter Webster of Georgia Institute of Technology's School of Earth and Atmospheric Sciences. The largest increases in the number of intense hurricanes occurred in the North Pacific, Southwest Pacific and the North and South Indian Oceans, with slightly smaller increases in the North Atlantic Ocean. The link between the global rise in sea surface temperatures and increased hurricane intensity is quite strong, Webster told IPS. Over the last 40 years, the top 300 metres of the world's oceans have warmed about 0.5C on average. Earlier this year, Tim Barnett, a marine physicist at the Scripps Institution of Oceanography, published a study that provided clear evidence that emissions of greenhouse gases from burning fossil fuels was responsible for ocean warming. Hurricane Katrina offers a good illustration of the role of warm water, Webster said. The Saffir-Simpson scale rates hurricanes from 1 to 5 according to wind speeds and destructive potential. A Category 1 storm has winds blowing continuously above 110 kilometres an hour: A Category 5 has continuous winds above 250 kilometres per hour. Trenberth recently published his own paper in Science about the link between human-induced climate change and increased hurricane intensity and rainfall. "Our estimate is that rainfall from Katrina was about seven percent enhanced by global warming," Trenberth said in an interview. He also points out that Kerry Emanuel, a leading hurricane expert at the Massachusetts Institute of Technology, released another study in Science showing that major storms have increased in intensity and duration by a whopping 70 percent in the North Atlantic and Northwest Pacific Oceans since the 1970s. It's important to note that Emanuel, Webster and Trenberth took different approaches to the issue, but all arrived at similar conclusions. Hurricanes and thunderstorms are climate regulating mechanisms for removing heat from the surface of oceans and land upwards and into space, Trenberth explains. With the extra heat that is trapped in the atmosphere and oceans by global warming, there has to be a corresponding increase either in the numbers or intensity of storms. What will the future be like when the oceans warm another 0.5 degrees C, as they inevitably will even if all human emissions of greenhouse gases were cut off today? More Category 4 and 5 storms and possibly beyond that towards what Emanuel and others have called "hypercanes", said Webster. Hypercanes is a speculative attempt to explain mass species extinctions 245 million years ago. Computer models showed that continent-sized super-storms with winds averaging 600 kilometres per hour could be produced if oceans warmed to an incredible 45 to 50 degrees C. Such temperatures are impossible today barring a ma