May 27, 2005

Antarctic Ice: A Global Warming Snow Job?

Climate scientists have long suspected that warming the oceans around a very cold continent is likely to dramatically increase snowfall. Consider Antarctica. It’s plenty chilly, dozens of degrees below freezing, and it’s surrounded by water. The warmer the water, the greater the evaporation from its surface, and, obviously, the more moisture it contributes to the local atmosphere.

So, when this moisture gets swirled up by a common cyclone, do you think it’s going to fall as rain in Antarctica?

A recent study, no shocker to real climatologists (but perhaps to climate doomsayers), demonstrates this simple physics. It appears in the latest SciencExpress, and it shows that the vast majority of the Antarctic landmass is rapidly gaining ice and snow cover.

May 16, 2005

Determining Climate Sensitivity from Volcanoes: Observations vs. Models

Recently there have been several papers published that have attempted to use the evolution of the earth’s temperature after big volcanic eruptions as a determinate of the earth’s climate sensitivity—that is, how much the average temperature changes with a change in climate forcing (i.e. a change of energy input). Having a good understanding of the climate sensitivity is key to having a good understanding of future climate change.

Oftentimes, the sensitivity is reported as the temperature change resulting from an energy change that is equivalent to the one assumed for a doubling of the atmospheric carbon dioxide levels (from pre-industrial values). In its 2001 Third Assessment Report (TAR) the Intergovernmental Panel on Climate Change (IPCC) settled on a value of 3.7 watts per meter squared (W/m2) (see out last article for more information on energy units) for the energy change associated with a doubling of CO2. That’s the easy part. Figuring out how much the earth’s average temperature will change as a result has proven to be much more difficult.

May 13, 2005

Climate Cycle or Climate Psychic?

Filed under: Climate History

In light of the general hysteria over global warming, it’s nice, once in a while, to be able to couch our current and ongoing climate changes into some larger perspective. We keep hearing about historically warm years, warm decades, or warm centuries, uncharacteristically long or severe droughts, etc. for which mankind’s striving for a high quality of life is to blame, via the internal combustion engine and its by-product, carbon dioxide. But in reality, in most cases, we have a tragically short record of good observations to really determine how much of a record we’re even close to setting.

For example, let’s take one fairly recent climate discovery called the Pacific Decadal Oscillation, or PDO. In the late 1990s, some west coast fisheries researchers noted cyclical behavior in the annual salmon harvest and tied it to a Pacific Ocean climate anomaly. It turns out that when the Pacific Ocean off of Southern California and the Baja Peninsula is warmer than normal at the water surface, temperatures are typically lower than normal in the north central Pacific well south of the Aleutians. This state, called the positive phase of the PDO, is also linked to dry conditions in the Pacific Northwest and the northern Rockies and above average rainfall in the Desert Southwest (see Figure1). In the opposite situation, negative PDO, you simply flip the sea-surface temperatures and precipitation patterns.

(Read more at Tech Central Station)

May 10, 2005

Global Warming: Something New Under the Sun?

Filed under: Aerosols, Climate Forcings, Solar

That appears to be what is happening, judging from three papers in the May 6 issue of Science.

These three papers argue that the amount of incoming solar radiation reaching the surface of the earth has increased dramatically in the last two decades. While the values vary from paper to paper, in toto the new studies suggest that the increase in solar radiation absorbed at the earth’s surface had almost 10 times as much warming power during that time as the concurrent increases in carbon dioxide, the main global warming gas. Therefore, the warming observed over the past 20 years must have little to do with changes in greenhouse gases.

Before you kill the greenhouse effect, please note that we think this is a lot of hooey. But if you accept these results, that’s where you have to go.

May 3, 2005

Nature Imitates Life!

Filed under: Climate Extremes, Hurricanes

If you just looked at the cover of April 21 issue of Nature magazine you’d see a hurricane apocalypse, as four major storms surround Florida.

They are in physically impossible proximity. Hurricanes require an “outflow” of winds aloft to continue upward motion in their tight and deadly vortices. In the picture, the outflows of three storms are on top of each other. They would mutually squash each other within hours.

However, if you go to Page ix, the “This Issue” section, you’ll get an explanation:

The 2004 US hurricane season was one of the worst on record. Four hurricanes struck Florida in August and September…On the cover (Courtesy Univ. Wisconsin-Madison, Space Science and Engineering Center) is a composite satellite image of hurricanes Charley, Frances, Ivan and Jeanne ‘approaching’ Florida in August and September 2004.

“Approaching,” indeed! I called my doctoral alma mater in Madison to find out what was going on, and they replied that they had initially provided another image with the dates superimposed over each storm—a much less provocative representation, which Nature declined as “too cluttered.”

Fine. Nature has built quite a reputation in recent years on climate hype (perhaps only equaled by its American counterpart, Science) and this is just another example.

Ironically, immediately below the description of the cover is a reference to a “News Feature” article on page 952, in the April 21 issue:

Picture Imperfect

The magic of digital photography and Photoshop means that scientists can manipulate images so that key features are visible. But there is a grey area between image enhancement and misrepresentation. Helen Pearson reports. [News Feature, p. 952]

Why bother separating these two paragraphs? Nature itself provided a fine example.

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