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Saturday, February 03, 2007

ACCORDING TO MANY, HUMAN ACTIVITY *MIGHT* CAUSE *SOME* GLOBAL WARMING - AND WHAT ARE THE IMPLICATIONS?

The headline above and the text excerpted below is how "The Australian" (national daily) reported the latest IPCC report.

It rightly notes the huge range in predictions offered and includes some skeptical comments.

The range of predictions is a bit like a fortune-teller saying to someone: "One day you will be either a Prince or a pauper". I doubt that such a totally vague fortune-teller would stay in business long...
"Scientists are now almost certain temperature increases over the last half of the 20th century were caused by human activity, and have warned of ominous further increases up to 4C by 2100.

The world's most significant weather forecast, released last night in Paris, revealed growing confidence in climate modeling that suggests greenhouse gases are reaching dangerous levels and need to be reduced. The first volume of the fourth assessment report by the UN Intergovernmental Panel on Climate Change has reported similar warming projections to its previous report six years ago.

The new report is based on the results of 23 climate models, a three-fold increase from the seven models used in 2001 to deliver best estimates of temperature increases ranging from 1.8C to 4C.

The increased number of models has widened the likely temperature ranges from 1.1C to 6.4C, compared with from 1.4C to 5.8C six years ago. [The 1.1C prediction is at least fairly consistent with the ACTUAL rise of .6C in the 20th century]

Significantly, the report finds man-made release of greenhouse gases is more than 90 per cent likely to have caused most of the observable increase in global average temperatures since the mid-20th century, about 0.65C.

The range of projected rises in global sea levels is from 0.18m [a mere 7 inches over an entire century] to 0.59m by 2100, driven largely by their expansion from rising water temperatures.

The IPCC also reports greater confidence in the projected patterns of warming and other regional-scale features, including contracting snow cover, shrinking sea ice on the poles and the high likelihood of more frequent hot extremes, heat-waves and heavy rainfall patterns.

The Antarctic ice sheets are predicted to remain too cold for widespread surface melting and are expected to gain in mass due to increased snowfall. While the Greenland ice sheet is projected to contribute to sea-level rises after 2100, the report says this will need to be sustained for millenniums to result in its complete elimination and a resulting sea-level rise of about 7m.....

In Melbourne, former head of the weather bureau's National Climate Centre William Kininmonth was among the sceptics. "My feeling is that the report is more alarmist than the evidence suggests," he said. He was particularly critical of the IPCC's interpretation of the data and of the separate computer modelling systems used to predict future climate changes. He added that, along with Canadian climate-change sceptic Ross McKitrick, he had contributed to an "independent summary for policymakers", to be released in London next Monday...."
Source

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RELIAPUNDIT: UPDATE: maybe you are being too kind to the report summary JR:

AJ STRATA:


[FIRST INDENTED SECTION IS FROM THE OFFICIAL REPORT SUMMARY; STRATA'S ANALYSIS FOLLOWS]

The research shows that between 1993 and 2006, sea levels rose by 3.3mm a year on average, while the 2001 IPCC report had predicted an annual rise of less than 2mm.

This is right at the upper limit of the uncertainty in the IPCC’s predictions due to very little data on how ice on land will respond to warming and how fast it will melt. If the climate follows this upper sea level prediction we will experience an 88cm rise in sea levels by the end of the century - much higher than the 14 - 43cm rise predicted under the IPCC’s most likely climate scenario.

A rise of close to 1m would threaten huge areas of low lying coastal land, as well as major cities such as London, New York and Tokyo.

Some things a scientist would note. First is the 3.3mm vs 2mm. Note that the period in question is from 1993 to 2006, 13 years. But the 2mm prediction was made in 2001 - five years ago. Now I would need to look at the data from the 2001 report, but what is should say (if the reporters are being accurate) is this. Over the 13 year period the the levels rose 42.9mm (let’s just call it 43mm). The earlier prediction was for it to rise 26mm over those 13 years. That earlier prediction was made in 2001 and supposedly would include the previous 8 years at 2mm/year. So one would assume the 2001 level had risen 16mm already (I don’t think it did, BTW).

So what does this mean? Well, for this story to be accurate the sea level would have had to make up some serious ground in the last 5 years and rise 27mm! That would be a rate of 5.4mm a year. Now this sounds absolutely astounding, until you realize we cannot measure sea levels globally to the millimeter level. And even if we did, the amounts we are talking about are inside the error bars. For example, the sea height ‘appears’ to be rising around New Orleans, but the truth is the land and sea bed are sinking. Is this an increase in sea hieght? Yes. Is it due to more water and less ice? No.

. Not surprisingly it operated from 1992-2006. For the propeller heads here is a report on its instrument performance over that time. It was nowhere near the mm level in measuring sea surface height (ssh). I don’t have time to go through the 13 years of reports, but my recollection has been is has not seen a significant change. The fidelity of this mission was in the centimeter range for on measurement. But the overall summary across the globe would be more on the fractions of a meter. So the 2-3.3mm range is a bit of a stretch. No one reports numbers like this without the error bars. Just like with polls, this is a statistically derived number and my guess is the error bars are larger then the number (e.g., +/- 5mm or more).

But let’s look at the last part of the screed to see how we jump from 2-3.3mm (fractions of an inch) to 3 feet, 3 inches in one kick dash.

This is right at the upper limit of the uncertainty in the IPCC’s predictions due to very little data on how ice on land will respond to warming and how fast it will melt. If the climate follows this upper sea level prediction we will experience an 88cm rise in sea levels by the end of the century - much higher than the 14 - 43cm rise predicted under the IPCC’s most likely climate scenario.

A rise of close to 1m would threaten huge areas of low lying coastal land, as well as major cities such as London, New York and Tokyo.

See how they go from mm/year to centimeters per century? And one has to wonder about their math. If I multioly 3.3mm/yr times 84 years (end of the century) I get 27 cm - not 88cm. So their models assume a continuous acceleration, which has not been seen ever. But more to the point is the clear propoganda BS at the end. 88cm is not just under 1 meter. They missed their decimeters (a measurement few use today). 88cm is 88/100th’s of a meter. [fixed the math - never do this is tandem with something else with constant interruptions!] In other words, at 88cm/century it would take 100 years to get to 1 meter in sea surface height.

So in the space of a few paragraphs we go from millimeters to meters, yet that time frame is possibly 100 years, or (given the range od 1-4 times the low end) maybe 400 years. And not a word in the article about these time frames. This is the art of propoganda - and it doesn’t belong in science, or articles on scientific speculation (which is what man-made global warming is). The day the Global Warming crowd can DEFINITIVELY measure how much of the warming is directly attributal to man then we can have a serious discussion.

RELIAPUNDIT: I THINK THE REPORT SUMMARY AND THE REPORT ARE BUNK. THE SCIENTISTS ARE TRYING TO PROVE WHAT THEY ALREADY BELIEVE.

GEO-HISTORY IS REPLETE WITH SIMILAR WARMING ERAS WHEN THERE WERE NO MAN-MADE INPUTS. END OF STORY.

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