Global Warming

A massive global increase in the number of strong hurricanes over the past 35 years is being blamed on global warming, by the most detailed study yet, New Scientist reveals.

The US scientists warn that Katrina-strength hurricanes could become the norm.

Worldwide since the 1970s, there has been a near-doubling in the number of Category 4 and 5 storms; the strength that saw Hurricane Katrina do such damage to the US Gulf coastline late in August 2005.

Peter Webster of the Georgia Institute of Technology, Atlanta, says
the trend is global,
has lasted over several decades
and is connected to a steady worldwide increase in tropical sea temperatures.

We can say with confidence that the trends in sea surface temperatures and hurricane intensity are connected to climate change, says Webster's co-author Judy Curry, also of the Georgia Institute of Technology

Democritus: Read more

New probe may silence climate sceptics, Nature reveals.

THOSE who deny global warming is happening often rely on somewhat error-prone satellite information about our planet. But a proposed probe could dramatically improve the accuracy of such readings and put an end to the climate change debate - at least as far as satellite evidence is concerned.

Climate change sceptics have often cited a 1992 analysis by John Christy of the University of Alabama in Huntsville, which showed that the troposphere had warmed only negligibly since satellite records began in 1979.
But many have argued that Christy's analysis ignored, among other things, uncertainties in the satellite data.
The uncertainty allows the sceptics to exist, says Nigel Fox of the UK's National Physical Laboratory near London.
As long as they can point to uncertain results, we won't be able to argue convincingly for climate change treaties, he says...
Once the satellite is in orbit, the only way to recalibrate the devices is to compare them with those on other satellites. But these sensors have also experienced a punishing launch and, in addition, may well have become less sensitive or lost their calibration over time...
...There is a not so insignificant uncertainty in observations of the Earth from space. For instance, the margin of error in measurements of the total solar radiation reaching Earth is about 0.3 per cent. While this might not seem much, a swing of 0.3 per cent could induce a 2 °C global temperature change - enough to trigger a mini ice age of the sort Europe experienced in the 17th century...
The need for accurate satellite data to quantify climate change is becoming urgent, says Joanna Haigh of the department of space and atmospheric physics at Imperial College London.
Fox says that the accuracy of such measurements could become crucial in settling international disputes over carbon trading...

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Energy Imbalance Behind Global Warming, LiveScience says.

Scientists have determined that more energy is being absorbed from the Sun than our planet reflects back to space. This energy imbalance, the researchers said today, confirms other predictions that Earth's climate will warm by about 1 degree Fahrenheit (0.6 Celsius) by the end of this century...
The imbalance is due to increased air pollution, especially carbon dioxide and other greenhouse gases that act like a see-through blanket, letting sunlit in but trapping the heat it generates...
If the imbalance were maintained for 10,000 years, it would melt enough ice to raise the oceans by six-tenths of a mile (1 kilometer), the scientists said. The analysis lends support to the contentious idea that humans are contributing to the warming trend...
This energy imbalance is the "smoking gun" that we have been looking for, said lead researcher James Hansen, director of NASA's Goddard Institute for Space Studies, part of the Earth Institute at Columbia University.
It shows that our estimates of the human-made and natural climate forcing agents are about right, and they are driving the Earth toward a warmer climate.
A study... confirmed that last year was among the four warmest on record and projected 2005 will be the warmest...
The previous work concluded that the seas will rise at least 4 inches (10 centimeters) this century, posing increased risks to coastal regions around the globe.
Since 1993, data from satellite altimeters, used to measure sea level, have shown that the world's oceans have risen by 3.2 centimeters (cm), or 1.26 inches, per decade (plus or minus 0.4 cm). That's twice as large as sea level rise in the last century.
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Global warming could trigger ant invasions, New Scientist warns.
Global warming may lead to an unexpected threat from the insect world - swarming invasions of tiny ants - suggests new research.
Global warming might shrink ant workers by as much as a third, says Michael Kaspari at the University of Oklahoma, US, and the Smithsonian Tropical Research Institute in Panama, who carried out the study. ...Ant invasions - already destructive - may become more common in a warming world.
Kaspari suggests that higher temperature may be a double-edged sword when organisms are growing: It allows you to forage, but a greater fraction of what you eat gets frittered away in metabolism.
Kaspari now plans to see if other organisms vary in size in such a predictable way, starting with the brown food web of decomposing organisms in soil.
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Key Argument for Global Warming Critics Evaporates, LiveScience
For years, skeptics of global warming have used satellite and weather balloon data to argue that climate models were wrong and that global warming isn't really happening.
Now, according to three new studies published in the journal Science, it turns out those conclusions based on satellite and weather balloon data were based on faulty analyses...
While surface thermometers have clearly shown that the Earth's surface is warming, satellite and weather balloon data have actually suggested the opposite...
But most people had to conclude, based on the fact that there were both satellite and balloon observations, that it really wasn't warming up, said Steven Sherwood, a geologists at Yale University and lead author of one of the studies.
Sherwood examined weather balloons known as radiosondes, which are capable of making direct measurements of atmospheric temperatures.
For the past 40 years, radiosonde temperature data have been collected from around the world twice each day, once during the day and once at night.
But while nighttime radiosonde measurements were consistent with climate models and theories showing a general warming trend, daytime measurements actually showed the atmosphere to be cooling since the 1970's.
Sherwood explains these discrepancies by pointing out that the older radiosonde instruments used in the 1970's were not as well shielded from sunlight as more recent models. What this means as that older radiosondes showed warmer temperature readings during the day because they were warmed by sunlight.
...Radiosondes are better insulated against the effects of sunlight, but if analyzed together with the old data - which showed temperatures that were actually warmer than they really were - the overall effect looked like the troposphere was cooling.
The discrepancy between surface and atmospheric measurements has been used by for years by skeptics who dispute claims of global warming.