October 10, 2005

Sea Level Rise: How High?

Filed under: Climate Models, Sea Level Rise

Global sea level rise figures prominently in most climate doom and gloom stories. And, not surprisingly, good news is either ignored or mis-reported.

First, a little history. The Intergovernmental Panel on Climate Change estimated, in its Third Assessment Report (2001), that between 1990 and 2100, the global average sea level will rise somewhere between 3.5 and 34.6 inches, with a central value of 18.9 inches. Of course, the values falling near the low end of the range are usually left out of global warming scare stories, while the values near the high end are prominently featured (e.g. see here and here).
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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.
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April 28, 2005

James Hansen Increasingly Insensitive

Filed under: Climate Models

It seems that the longer NASA scientist Jim Hansen studies the climate, the more insensitive he, or should we say, his interpretation of the climate, becomes.

Climate “sensitivity” is the change in surface temperature expected for each additional Watt of energy that is re-radiated onto the earth’s surface and lower atmosphere by slight changes in the greenhouse effect. The main cause of these changes in the greenhouse effect, of course, is the increasing levels of atmospheric carbon dioxide caused by the combustion of fossil fuels.

You would think that it would be big news when Hansen—the guy who started all this mess with his incendiary 1988 congressional testimony—lowers his estimate for the sensitivity to two-thirds of the value he used back then.

After all, he does get a lot of ink. That’s what happened in October, 2004, when he traveled to hotly contested and environmentally sensitive Iowa the weekend before the election, and publicly berated his Boss’ global warming policy. Talk about insensitive!

Hansen’s most recent figure, just published in Sciencexpress, is that the surface temperature ultimately changes 0.67˚C per Watt per square meter (W/m2). In 1988 he said it was a full degree, and in 2001 he lowered it to 0.75.

The lower the climate sensitivity, the less that the global temperature will rise in the future (given the same amount atmospheric carbon dioxide) and the lower the threat of catastrophic climate change.
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March 11, 2005

Less Cooling, Less Warming

Filed under: Climate Models

Newly published results show that the degree to which sulfate aerosols lead to surface cooling is overestimated in current climate models. This result further undermines what little support remains for the IPCC’s high-end warming projections.
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March 2, 2005

Snowjobs About Weather and Climate

Filed under: Climate Models

Want to raise the blood pressure of an entire region? If you’re within a few hundred miles of Washington DC, just say “snow” to a TV camera. But if you’re more interested in planetary hypertension, simply substitute the words “global warming”.

It turns out that the forecasting methods for both snow and global warming are quite similar. And what happened with the Mid-Atlantic snowstorm of February 28 tells us much about the climate of the next 100 years.
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February 7, 2005

No proof is sufficient

Filed under: Climate Models, Droughts

In the face of evidence resulting from their own research, some scientists refuse to abandon their preconceived idea: that computer-based climate models reliably forecast future climate.

We’ve come across research published in the peer-reviewed journal Geophysical Research Letters, the title of which pushes the limits of scientific acceptability: “Forty-five years of observed moisture in the Ukraine: No summer desiccation (yet).” It appears we have now entered a phase of the global climate change debate wherein scientists begin to trumpet their personal bias even if it runs contrary to evidence compiled by the scientific entity they represent or, even more astounding, if it runs counter to research results they themselves produce!
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October 4, 2004

Not a Model World

Will future hurricanes will be stronger in a greenhouse-gas warmed world? A new climate model says yes, but (as usual) the observations suggest otherwise.

With all the hurricane activity as of late—both in the Atlantic Ocean and in the U.S. media—we’re starting to hear rumblings conflating hurricanes and global warming. Renowned hurricane experts say that notion is unfounded, given actual observations.
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August 31, 2004

Trying Times

Though the new U.S. Climate Change Science Program report concedes numerous climate modeling unknowns, a New York Times editorial misrepresents it as a “striking shift” by the Bush Administration.

Well, you can’t fault the New York Times for trying—that is, trying to move its global warming agenda forward by any means necessary. On August 26, a routine federal report on climate change research was hailed as “a striking shift” of the Bush Administration, and then used as the basis for a masthead editorial August 27 calling for reductions in carbon dioxide emissions.

In reality, the report, Our Changing Planet: The U.S. Climate Change Science Program for Fiscal Years 2004 and 2005 (OCP ) resembles a jillion other climate reports with interminable titles emanating from our Washington agencies. University faculty mailboxes groan with this overload. (Whatever became of the paperless office, we ask?)
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August 17, 2004

California Nightmare

It’s increasingly difficult to keep a straight face while reading any global warming paper in a major scientific journal. Even by this standard, a recent article on deaths in California and destruction of its wine industry (of course, because of dreaded global warming) is a true belly-slapper.

The fact that it appeared in the Proceedings of the National Academy of Sciences (PNAS) is a lot less funny. What on earth is happening to the peer-review process in science, and how are papers this bad getting through that process?
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August 9, 2004

Non-linear Climate Change

Climate models generally depict global temperatures changes as smooth, nearly linear increases, in accordance with the relatively smooth increase in climate forcing agents. But real world observations show that climate change is not quite that well-behaved.
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