August 31, 2007

More Hurricane News

Filed under: Climate Extremes, Hurricanes

Of all the global climate related news we cover at World Climate Report, we seem to spend more time on hurricanes (a.k.a., tropical cyclones) than any other subject. We could feature a prominent scientific article on hurricanes every month, and despite the evidence to the contrary, popular presentations on the consequences of increased greenhouse gas concentrations never fail to include something about the great threat we face from more and more hurricanes. As we have noted many times before, the United Nations Intergovernmental Panel on Climate Change (IPCC) clearly states in the Summary for Policymakers “There is no clear trend in the annual numbers of tropical cyclones.”

An article appears in a recent issue of the prestigious Nature magazine that at first might change the minds of the IPCC with the first sentence in the abstract stating “Hurricane activity in the North Atlantic Ocean has increased significantly since 1995.” The article is by a group of scientists from institutions in Sweden, Puerto Rico, Florida, Colorado, and Texas who focused their research of hurricane activity in the Atlantic Ocean. What starts out looking like a dream come true for the global warming crusade soon deteriorates into their nightmare.

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August 29, 2007

Hurricanes Down Under

Filed under: Climate Extremes, Hurricanes

First things first – the title is wrong. We have presented many essays recently showing that hurricane activity is not increasing in terms of frequency and intensity or that any increase is simply a return to what was commonly observed decades or centuries ago. When we were writing about hurricanes in the Atlantic Ocean, Caribbean Sea, or Gulf of Mexico (or even the Northeast Pacific), our use of the term “hurricane” was correct. These severe tropical storms appear in many other parts of the world, and when they occur over the Northwest Pacific Ocean and west of the International Date Line, they are called typhoons. “Hurricanes” near Australia and in the Indian Ocean are sometimes called Willy-Willies by the locals. However, in the scientific community, hurricanes, typhoons, and Willy-Willies are all called tropical cyclones.

For a variety of reasons, most of the research we have reviewed has been conducted in the Northern Hemisphere on tropical cyclone trends that have occurred in the Northern Hemisphere. However, the Southern Hemisphere gets its fair share of tropical cyclones, and the global warming supporters do not differentiate hemispherically in their never-ending claims that elevated concentrations of greenhouse gases will cause an increase in tropical cyclone frequency and/or intensity.

An interesting article has appeared in Earth and Planetary Science Letters regarding tropical cyclone activity in northeastern Australia over the past eight centuries. Eight centuries? A researcher would need to be very clever to figure out the number of large tropical cyclones that occurred every year from AD 1226 to AD 2003 in northeastern Australia.

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August 23, 2007

Taming the Hurricane

On September 28, 1955, a Category 5 hurricane named Janet slammed into Chetumal, on Mexico’s Yucatan Peninsula, killing over 600 people.

Hurricane Dean, another Category 5, and the third-strongest storm ever measured at landfall, hit in exactly the same place earlier this week (Tuesday, August 21,2007) and killed no one. Maximum winds in both storms were indistinguishable. The hurricane-hunter pilot who flew through the eyewall of the storm Tuesday reported severe turbulence, which is a temporary loss of aircraft control. Probably for the first time in human history, a Category 5 storm hit a populated area and everyone lived.

Because of its peculiar location, the Yucatan takes more big hurricane hits than just about anywhere else in the western hemisphere. When Mexico was dirt-poor, as it was in 1955, hurricanes could kill hundreds. They were warned, then, too. Hurricane-hunter planes also monitored Janet. Only one of these has ever been lost, and it as Janet was making landfall.

Similar storms, huge storms, very different results. What’s happening here?

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August 22, 2007

Ocean Circulation Slowdown: False Alarm

We are sure many of you remember headlines similar to these: “Global Warming to Cause Next Ice Age!” or “Global Warming to Send Europe into a Deep Freeze!” In fact, next time New England or Europe has a cold winter, we’ll guarantee that you’ll see them again. The idea behind this scare story (and the premise of the climatefright film The Day After Tomorrow) is that the ocean’s thermohaline circulation (which among other things modestly warms the winter climate of western Europe) slows down, or even worse stops, sending the climate into disarray—all because of anthropogenic global warming. In the case of The Day After Tomorrow, this circulation shut down led to a flash freeze of the planet, while more “reasonable” climate alarmists at least give it a couple of decades to turn Europe into the icebox. But, in reality, things just don’t seem to be headed that way at all.

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August 21, 2007

Tellus More About Hurricanes

Filed under: Climate Extremes, Hurricanes

Tellus is a professional scientific journal published on behalf of the International Meteorological Institute in Stockholm and is highly respected by atmospheric scientists throughout the world. A recent issue is devoted to hurricanes (a.k.a., tropical cyclones), and three articles in the issue are of significant interest to us at World Climate Report.

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August 17, 2007

Climate Change Chaos

Filed under: Climate Forcings, Solar

Climate scientists have known for many years that the energy output from the Sun varies and believe it or not, when the Sun is putting out more energy, the Earth heats up and when the Sun cools down, so does the Earth. What appears to be so simple is actually much more complex as the Sun can vary its output differentially in the various portions of the electromagnetic spectrum. For example, the Sun can actually increase its production of gamma rays while decreasing the level of infrared emission, and these patterns of energy output can reveal themselves quite differently in terms of response of Earth’s climate.

Nonetheless, over the past century, the correlation between solar irradiance (in Watts per square meter) and the planetary temperature anomaly (in °C) is highly statistically significant; the Pearson product-moment correlation coefficient is 0.51 and is beyond the 0.99 level of statistical confidence (see below). The line on the plot basically represents a simple statistical linear “model” that predicts the planetary temperature anomaly given a specific output level of the Sun. For every year we could examine the difference between the observed temperature anomaly and the predicted anomaly given solar output – the difference (observed – predicted) is called the residual which should have a mean of zero over the study period. The residuals should fluctuate from year to year, and they should behave in a random fashion.


Scatterplot of annual solar irradiance values (in Watts per square meter) and the annual global near-surface temperature anomalies (in °C) over the period 1910-2003 (from Balling and Sen Roy, 2005)

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August 14, 2007

The Iris Opens Again?

Back in 2001, Richard Lindzen and colleagues made quite a stir in the climate community when they published a paper in the Bulletin of the American Meteorological Society in which they describe having possibly identified an “adaptive infrared iris” that opens and closes to keep the earth’s temperature fairly steady even in light of increasing atmospheric carbon dioxide levels. It was proposed to work something like this—when the temperature in the tropical oceans begins to warm up, it causes in increase in the amount of low-level water clouds and an even greater decrease in total coverage of high-altitude ice clouds. Since ice clouds are net warmers (that is, they trap more outgoing longwave radiation (heat) than they reflect away incoming shortwave (solar) radiation) and water clouds are (generally) net coolers (reflecting back to space more incoming solar shortwave radiation than they absorb outgoing longwave radiation), more of the latter and a lot less of the former leads to a net cooling, and the temperatures of the tropical oceans decrease. However, cooler tropical ocean temperatures lead to less low-level (water) clouds and more high altitude ice clouds. This configuration tends to lead to a net radiation increase and to higher temperatures. And the cycle starts over again. Lindzen’s moniker “adaptive infrared iris” refers to the mechanism in which the tropical ice cloud cover opens and closes in response to tropical ocean temperatures to allow more heat to escape to space when the oceans are warm and less heat to escape to space when the oceans are relatively cool (much like the iris of an eye which opens and closes in response to varying light levels to try to maintain a constant level falling on the retina). Lindzen et al. proposed that the iris acts as a global thermostat that will keep the earth’s temperatures from rising very far even as atmospheric concentrations of greenhouse gases increase.

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August 10, 2007

Future Air Pollution Levels and Climate Change: A Step Toward Realism

Filed under: Aerosols, Climate Forcings

Guest Commentary

Joel Schwartz
Visiting Fellow
American Enterprise Institute

What happens to future air pollution if the climate warms? Efthimios Tagaris and colleagues (Tagaris et al., 2007) have come closer than anyone before them in providing a realistic answer to this question. They predict that between 2001 and 2050, mean summer 8-hour ozone levels over the U.S. will decline by 11% to 28%, depending on the region, with an average decline of 20%. Fine particulate matter (PM2.5) will decline by 9% to 32%, with an average decline of 23%.

Tagaris et al.’s results stand in marked contrast to previous studies, nearly all of which predict higher air pollution levels over the U.S. in the future (e.g., Knowlton et al. (2004), Mickley et al. (2004), and Sitch et al. (2007)).

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August 8, 2007

Clouding Asian Warming

In 1998, Balling et al. published an article in Climate Research dealing with summer and winter warming rates in several widely-used gridded temperature time series. As seen in Figure 1 below, the Balling crew (which includes several World Climate Report team members) found that winters were warming far more than summers, based on near-surface thermometer records, for a large part of northern and central Asia over the period 1946-1995. We repeated the analyses for the satellite-based lower-tropospheric temperature measurements over the period 1979-1995 and found the same red blob (wamer temperatures) over northern and central Asia. We suggested in the article that the build-up of greenhouse gases would most impact the coldest and driest air masses of the world, which just happen to be the air masses that cover northern and central Asia in the winter. Elevated greenhouse gas concentrations in warm and moist air masses would have less of an effect given the overwhelming greenhouse effect of naturally occurring water vapor. We had produced what appeared to be a smoking gun – the greenhouse “fingerprint” looked rather obvious in our analyses. Of course, finding that the coldest and driest air masses of the planet were warming slightly is seen by some as a blessing and not a great cause for concern – are residents of northern Siberia really worried about their winters being a bit warmer?


Figure 1. Seasonal difference (winter minus summer) in temperature trends (°C per decade) for the thermometer-based near-surface data over the period 1946-1995 (from Balling et al., 1998).

Well, the smoking gun has become a bit cloudier given a recent article in Nature entitled “Warming trends in Asia amplified by brown cloud solar absorption.”

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