A Fact-based Response to Climate Skeptics - J.E. Robertson

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A Fact-based Response to Climate Skeptics
20 February 2010 :: J.E. Robertson

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In response to a recent article, explaining that record snowfall in certain places does not equate to a proof that global warming is not happening, but rather, that global warming is an apt explanation for why the record snowfalls would occur there, a number of climate skeptics chose to attack certain points in the piece, using what they take to be established science. In some cases, the evidence cited was simply misrepresented or misinterpreted, according to the wishes of the skeptics themselves.

For instance, one commenter wrote the following:

What does NASA satellite data tell us? “Unlike the surface-based temperatures, global temperature measurements of the Earth’s lower atmosphere obtained from satellites reveal no definitive warming trend over the past two decades. The slight trend that is in the data actually appears to be downward. The largest fluctuations in the satellite temperature data are not from any man-made activity, but from natural phenomena such as large volcanic eruptions from Mt. Pinatubo, and from El Niño. So the programs which model global warming in a computer say the temperature of the Earth’s lower atmosphere should be going up markedly, but actual measurements of the temperature of the lower atmosphere reveal no such pronounced activity. “

This report from October 1997 was cited in the same comment as proof that in fact global warming is a myth. The report does not say that. In fact, it specifically deals with questions about the accuracy of the very technology the commenter cites as proving the claim that a cooling trend exists while a warming trend does not. It’s important to remember that, first of all, the information is 13 years old, and the purpose of the linked report was to explore whether or not satellite data could be used to track atmospheric temperature fluctuations, at the time, not an entirely proven science.

There is also the problem of the comment’s premise: that lower atmospheric temperatures and surface temperatures cannot be different or that if lower atmospheric temperatures cool, surface temperatures could not warm or the warming would be cancelled out. The truth is that an increased difference between surface temperature (remember, we live at the surface; ocean temperature, glaciers and ice-melt are also at the surface) and temperatures in the lower atmosphere can lead to even more severe storms and climate-related environmental impact.

That temperature difference means stronger winds, and those winds cause climate phenomena to move, which is how we get weather. If surface temperatures are warming, the warming itself will also be more widespread due to increased wind activity. Winds are the engine of climate; they carry masses of low and high pressure, determine monsoon rain patterns and align weather systems over whole regions over extended periods of time.

The commenter fails to even consider this issue, because the intent of the comment was not to illustrate a matter of fact, but to use an apparently unrelated study —one exploring the criticism of the very point he is trying to make—, from 13 years ago, to discredit a vaguely defined “view” held today. In fact, that vaguely defined view is the consensus of the vast majority of scientists involved in climate research the world over, a consensus built on hard evidence and observable fact, and informed with the most advanced scientific peer-review process we have.

The skeptic commenter’s attack on the climate consensus conveniently ignores actual reporting on what is observed in terms of global average temperatures, the warming trend and the human role in driving that trend. It’s worth looking at what NASA’s climate scientists say about warming trends, 13 years after addressing the problem of whether satellite measurements were accurate enough to deliver reliable data.

On 21 January 2010, NASA released a report entitled “2009: Second Warmest Year on Record; End of Warmest Decade”. That warmest decade report shows a clear evidence of a sustained warming trend from the year 1880 through the present. The data come from the Goddard Institute for Space Studies (GISS), the most advanced climate measuring scientific institution in the world.

The climate-skeptic commenter alleges there is a proven cooling trend and that “The largest fluctuations in the satellite temperature data are not from any man-made activity, but from natural phenomena such as large volcanic eruptions from Mt. Pinatubo, and from El Niño.”

In fact, NASA’s GISS findings show a marked upward trend in global average temperature, increasing dramatically over the last half-century, with the last decade clearly the warmest ever recorded. Regarding El Niño, there is recognition that the “unusually high temperatures” for 1998 might be in part attributable to that phenomenon, but El Niño shifts weather patterns within a specific latitudinal range, and does not explain long-term global trends in average temperature.

NASA’s warmest-decade report reads:

A deep solar minimum has made sunspots a rarity in the last few years. Such lulls in solar activity, which can cause the total amount of energy given off by the Sun to decrease by about a tenth of a percent, typically spur surface temperature to dip slightly. Overall, solar minimums and maximums are thought to produce no more than 0.1°C (0.18°F) of cooling or warming.

“In 2009, it was clear that even the deepest solar minimum in the period of satellite data hasn’t stopped global warming from continuing,” said Hansen.

Small particles in the atmosphere called aerosols can also affect the climate. Volcanoes are powerful sources of sulfate aerosols that counteract global warming by reflecting incoming solar radiation back into space. In the past, large eruptions at Mount Pinatubo in the Philippines and El Chichón in Mexico have caused global dips in surface temperature of as much as 0.3°C (0.54°F). But volcanic eruptions in 2009 have not had a significant impact.”

So, while volcanic eruptions can cause temperature fluctuations, they cause cooling, not warming, and in the period from 1880 to the present, that effect has not overridden the significant warming trend. NASA specifies that in fact the period 2000 to 2009 (not part of the 1997 report) is clearly the warmest decade on record.

The second point raised by the commenter was...

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More: http://www.casavaria.com/cafesentido/2010/02/20/6069/a-fact-based-response-to-climate-skeptics/

It's so refreshing to listen to actual experts...

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