"Storms tend to run on multi-decadal cycles, so it's difficult to tell from year to year whether the number of hurricanes is really on the rise. So far that doesn't seem to be the case, with the overall number of storms worldwide holding about steady ”in fact, some scientists argue that warming might actually bring about a reduction in the overall frequency of storms. But the Nature paper argues that warmer sea-surface temperatures will result in stronger storms, because hotter oceans mean the developing storms can draw more warm air, which powers the storm. "Hurricanes are driven by the transfer of energy from the ocean to the atmosphere," says Kerry Emanuel, a meterologist at the Massachusetts Institute of Technology. "As water warms, the ability of water to evaporate goes up, and a greater evaporation rate will produce a more intense hurricane."

"So far, tropical ocean temperatures have risen by about 0.5 degree C since 1970, which could explain the more powerful storms. The Nature researchers estimate that every 1 degree C increase in sea-surface temperature would result in a 31% increase in the global frequency of category 4 and 5 storms. Given that computer models indicate that ocean temperatures could rise by up to 2 degrees C by 2100, those are scary calculations. It's especially worrying because the most intense storms do the most damage by far "several minor storms can equal the damage of a single severe hurricane. "The category 1 or 2 storms don't do that much," says Emanuel. "It's the 3 and 4 storms that really do the damage, and we could see more of them."

"As population numbers and property development grow in vulnerable areas like the Gulf Coast, natural disasters will get worse even without the effect of warming. Think of the damage that hurricans have caused even without the possible effect of warming: Hurricane Camille in 1969, which caused over $9 billion in damages, and Hurricane Andrew in 1992, which caused $38 billion in damages. Now imagine those storms potentially amplified by the unpredictable effect of global warming. We need to be prepared. Gustav caused far less damage than Katrina because it was a weaker storm, yes, but also because we were ready this time. But we also need to reduce carbon emissions and blunt climate change ”or we may experience storms for which there is no preparation."

And another study McClatchy Newspapers reports shows that increased temperatures in the Northern Hemisphere in the past few decades exceeds that of the last 1,300 years.

"A new scientific study adds evidence that temperatures in the Northern Hemisphere fluctuated a bit over time, but that the sharp increase during the past few decades is bigger than anything in at least 1,300 years.

"The report was published Tuesday in the Proceedings of the National Academy of Sciences. Its conclusion is that temperature increased and decreased a little over the centuries, but the fluctuations were small enough that the line was roughly flat, like the shaft of a horizontal hockey stick. Then, from about 1980 to now, temperature increased sharply, more than any increase before” like the blade of the hockey stick.

"For the past 10 years, climate-change skeptics have been calling the hockey stick bogus. Now the scientists who studied the climate record and produced the original hockey-stick graph have done a new study using more data from more sources” and they got the same pattern.

"The new study "establishes further evidence that the recent warming isn't just part of a typical cycle," said climatologist Michael Mann, director of the Earth System Science Center at Pennsylvania State University."

"Of course, this alone doesn't establish the cause of that warming ”that it must be due to human influences," Mann said. That's left to other scientific studies of the climate.

Forces of nature ”changes in the output of the sun's energy and volcanic eruptions” and random variation explain the changes in climate before industrial times, Mann said. But only if human factors are taken into account ”particularly the production of long-lasting, heat-trapping gases from burning fossil fuels” can scientists explain the unusually high recent temperature increase, he said.