My earlier post “The Case Against the IPCC and Proponents of Dangerous Anthropological Global Warming” received many comments so I decided to elevate one exchange to post status. The exchange is between”John Parsons” (hereinafter called JP) and “Adam.” The names are in quotes because I don’t know if they are real. JP is apparently a true believer in anthropogenic global warming (AGW), meaning that he contends that carbon dioxide from burning fossil fuels is the main cause of recent warming and that global warming is dangerous. JP is a frequent commenter and tries to rebut issues in many of my posts. Adam is apparently a climate skeptic, meaning that he says there is no physical evidence that carbon dioxide is the main cause of warming.
I have frequently asked JP to present some physical evidence to support his position. In one long comment he presents what he considers evidence derived, he says from NASA and The National Climate Data Center. Adam gives references as he goes along. To avoid much duplication I will go point by point. You can read the complete exchange by going to the comment section of the cited post. I have added a few of my own comments to the discussion.
JP: Jon, You’ve seen the evidence. But because you now say you haven’t, here it is.
Global sea level rose about 17 centimeters (6.7 inches) in the last century.
Adam: But that says nothing about what forces caused the sea level to rise. There is no evidence it was due to CO2.
Wryheat: Sea level has been rising at variable rates for at least the past 15,000 years.
JP: The rate [in sea level rise] in the last decade, however, is nearly double that of the last century.”
Adam: “Complete nonsense. There was no significant upward trend in the rate of sea level rise over the past decade, and the rate has actually slowed over the past 6 years.”
Wryheat: The rate of sea level rise is cyclical on a period approximately equal to solar cycles, see Sea Level Rising? A study of longer-term sea level fluctuations found the mean rate of global sea level rise was “larger in the early part of the last century (2.03 ± 0.35 mm/yr 1904-1953), in comparison with the latter part (1.45 ± 0.34 mm/yr 1954-2003).” (Holgate, S.J. 2007. On the decadal rates of sea level change during the twentieth century. Geophysical Research Letters 34: 10.1029/2006GL028492)
JP: “Most of this warming has occurred since the 1970s, with the 20 warmest years having occurred since 1981 and with all 10 of the warmest years occurring in the past 12 years.
Adam: Most of that is probably due to the urban heat island effect since the satellites show a lot less warming over the same period.
Wryheat: JP is referring to land surface temperatures. A survey of the U.S. Historic Climate Network shows that 70% of surface stations have a warming bias of greater than 2 °C due to poor siting and the urban heat island effect. JP’s contention is also an example of cherry-picking starting points. In the 1970s, the planet was in a cooling phase and headlines speculated on the possibility of a new “ice age.” NASA data show that 1934 was the warmest year of the last 100 years. Dr. Richard Keen, University of Colorado, says “More than half of the state and provincial maximum temperature records were set during the single decade of the 1930’s, and only 29 percent of these records were set since 1950.” See graph from NOAA of U.S. Climate Extremes Index here.
Of late, however, NASA has again been revising the historic temperature records to make the past seem cooler and the present seem warmer, see here.
JP: Even though the 2000s witnessed a solar output decline resulting in an unusually deep solar minimum in 2007-2009, surface temperatures continue to increase.
Adam: No they didn’t. See:
Wryheat: Temperatures tend to lag solar cycles. (Qian, W.-H. and Lu, B. 2010. Periodic oscillations in millennial global-mean temperature and their causes. Chinese Science Bulletin 55: 4052-4057)
JP: The oceans have absorbed much of this increased heat, with the top 700 meters (about 2,300 feet) of ocean showing warming of 0.302 degrees Fahrenheit since 1969.
Adam: Except the heat is actually a lot less than what the models predicted. This is strong evidence against the CAGW theory. These references show that the ocean is cooling:
Wryheat: 0.302 degrees, not 0.301 degrees? Given many sources of error in measurements and computation, it is ridiculous to claim an accuracy of three decimal places.
JP: Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades.
Adam: That’s evidence of warming, not what caused the warming. Read the papers on the arctic.
JP: In 1970, NASA launched the IRIS satellite measuring infrared spectra, and in 1996, the Japanese Space Agency launched the IMG satellite which recorded similar observations. Both sets of data were compared to discern any changes in outgoing radiation over the 26 year period. What they found was a drop in outgoing radiation at the wavelength bands that greenhouse gases such as CO2 and methane (CH4) absorb energy. The change in outgoing radiation was consistent with theoretical expectations. Thus we have found direct experimental evidence for a significant increase in the Earth’s greenhouse effect. This result has been confirmed by subsequent papers using data from later satellites. Hence we expect to find more infrared radiation heading downwards. Surface measurements from 1973 to 2008 find an increasing trend of infrared radiation returning to earth.
Adam: Read these links:
Wryheat: This contention is still very controversial, because it depends on how the relationship between forcing and feedback is interpreted. Water vapor increases in a warming atmosphere and water vapor absorbs infrared radiation at three of the four specific wavelengths that carbon dioxide absorbs. Nitrous oxide and, to some extent, oxygen absorbs infrared radiation at the fourth wavelength. In some papers the data are interpreted as a decrease in outgoing long wave radiation, in others, just the opposite. In still other interpretations there was no difference between early and later satellite measurements. Apparently the amount of outgoing radiation is always in flux. The comparisons are confounded by humidity and cloud cover, and it apparently depends also whether or not the readings were taken over land or over ocean, and at what season of the year. The data is subject to confirmation bias, i.e., you see what you want to see. This still does not constitute evidence that carbon dioxide is the main player.
JP: The planet’s total heat build up can be derived by adding up the heat content from the ocean, atmosphere, land and ice. Ocean heat content was determined down to 3000 meters deep.
Adam: Read the other links I provided. In fact a new paper has just been published, showing the heat is missing.
JP: The list of evidence I provided is a compilation of statements of facts from NASA, NCDC and NOAA. Only the opening and closing sentences are mine. If you disagree with their findings you should contact them and let them know how they have erred.
Adam: That is simply argument from authority. It’s not a valid argument.
JP: How is it that the facts from the work of NASA scientists are an “appeal to authority” but the scientists you reference are not?
Adam: Because you don’t seem to understand the difference between “claims” and “facts”. You did not present facts in your comment, you provided claims. And those claims were not supported by real world evidence. They contradicted the facts. So therefore repeating claims and claiming that they are “facts” simply because they are from NASA is indeed argument from authority.
JP: I purposely left out the citations that accompanied the claims made by NASA, NCDC and NOAA. The comment was just too unwieldy with them and their websites make their references easily available.
Wryheat: For a good review comparing government claims to facts see an essay by Dr. Craig Loehle here.
JP: Adam, you know that GHG’s add to the Earth’s radiative budget. You don’t need to search out a mysterious mechanism that cancels out the effect they have, and then search still further for another as yet unknown force that adds that same or similar effect back into the system.
Wryheat: That mysterious mechanism is called weather. Greenhouse theory seems to ignore convective heat transfer which mixes the atmosphere and transports heat to where it can more readily radiate into space. That allows more heat to escape into space than otherwise would in an idealized clear-sky, still-air greenhouse.
(Lindzen and Choi, 2011, On the Observational Determination of Climate Sensitivity and Its Implications, Asia-Pacific J. Atmos. Sci., 47(4), 377-390. AND Lindzen et al.,2007, Does the Earth Have an Adaptive Infrared Iris?, Bulletin of the American Meteorological Society.)
JP: Adam, many who deny the obvious about AGW have a powerful political motive.
Adam:Complete nonsense. Do all these scientists have political motives.
Wryheat: See how JP deflects the argument away from the main issue.
JP: Please don’t keep saying you haven’t seen the evidence.
Wryheat: Sorry JP, all the phenomena you describe have an explanation in natural variation. Your “evidence” is equivocal and contains no smoking gun. This all makes for great scientific debate, but when economically significant political policy decisions are based on equivocal “evidence” we see that it is the AGW hypothesis itself that is the real danger.
To potential commenters: Keep it civil and on point, otherwise your comments will be deleted.