A soon to be published research paper from the University of Arizona states that rising sea levels will flood our southeast coast. The press release is titled: “Rising seas will affect major US coastal cities by 2100.” The research was conducted by Jeremy Weiss, a doctoral candidate in geosciences, Jonathan Overpeck, professor of geosciences and of atmospheric sciences and co-director of UA’s Institute of the Environment, and Ben Strauss of Climate Central in Princeton, N.J.
The press release says that greenhouse gas emissions will cause warming which will raise sea level by at least one meter by the year 2100. It also says that “warming will likely lock us into at least 4 to 6 meters of sea-level rise in subsequent centuries…”
In my opinion, this study is nothing more than speculative science fiction with little factual basis and it presents just another scary scenario that begs for government grant money.
I emailed Mr. Weiss asking for information on their sea level projections and asked this question: “What specific physical evidence do you have that carbon dioxide has a significant effect on global temperature?” He emailed some references to me (see below).
On Sea Level
For sea level to rise one meter by 2,100 would require the current rate of sea level rise to more than triple beginning this year and continue for 89 years. For a review on measurements of sea level, see my blog: Sea Level Rising. Research documented in that article shows that sea level, as measured by world-wide tidal gauges, was rising 2.03 ± 0.35 mm/yr from 1904-1953 and 1.45 ± 0.34 mm/yr from 1954-2003. Satellite measurements indicate a rate of 3.2 mm/yr since 1994 with a decreasing rate since 2006. The apparent discrepancy between tidal gauges and satellite measurement is due to the fact that sea level rise is cyclic and the satellites started measuring at the bottom of a rising cycle. However, even using the higher number, it would require tripling of the currant rate of rise to produce a one meter sea level change by 2100.
In the press release, Weiss claimed to use “the most recent sea-level-rise science…” He referred me to two papers:
Pfeffer WT, Harper JT, O’Neel S (2008) Kinematic constraints on glacier contributions to 21st-century sea-level rise. Science 321:1340-1343.
The Pfeffer research was a computer modeling study but with no actual measurements. The abstract reads in part, “We find that a total sea-level rise of about 2 meters by 2100 could occur under physically possible glaciological conditions but only if all variables are quickly accelerated to extremely high limits. More plausible but still accelerated conditions lead to total sea-level rise by 2100 of about 0.8 meter.”
The other paper was: Vermeer M, and Rahmstorf S., 2009, Global sea level linked to global temperature. P Natl Acad Sci USA 106:21527-21532. This too is essentially computer modeling. I found two critiques of the Vermeer-Rahmstorf paper, one in the Proceedings of the National Academy of Sciences says their math was wrong; the other by a Senior Scientist at the US Department of Energy’s National Renewable Energy Laboratory lists multiple problems, including using out of date data and bad math.
Greenhouse gases and global warming
The “greenhouse effect” is this: solar radiation penetrates the atmosphere and warms the surface of the earth. The earth’s surface radiates thermal energy (infrared radiation) back into space. Some of this radiation is absorbed and re-radiated by clouds, water vapor, methane, carbon dioxide, and other gases. Water vapor is the principle greenhouse gas; the others are minor players. Without the greenhouse effect the planet would be an iceball, about 34 C colder than it is.
Since the press release said that greenhouse gas emissions (i.e., carbon dioxide) were responsible for the warming that would raise sea levels, I asked Mr. Weiss, “What specific physical evidence do you have that carbon dioxide has a significant effect on global temperature?”
At first, he emailed reference to two old textbooks and referred specifically to a chapter in one of them. I found that book online via Google Books. That chapter discusses the theoretical basis for climate modeling but presents no physical evidence to support the theory.
I asked again for sources and Mr. Weiss emailed links to abstracts of several papers in the scientific literature. It often requires a paid subscription to find the full paper online, but I did find some of them. Here are my comments on the papers Mr. Weiss referred to.
1. Harries, J.E., Brindley, H.E., Sagoo, P.J. and Bantges, R.J. 2001. Increases in greenhouse forcing inferred from the outgoing longwave radiation spectra of the Earth in 1970 and 1997. Nature 410: 355-357.
2. Jennifer A. Griggs and John E. Harries, “Comparison of spectrally resolved outgoing longwave data between 1970 and present”, Proc. SPIE 5543, 164 (2004); doi:10.1117/12.556803
These two papers use satellite data to compare the strength of the greenhouse effect at two different times. A review from CO2Science.org says:
Harries et al. (2001) analyzed the difference between the spectra of outgoing longwave radiation obtained by two orbiting spacecraft that looked down upon the earth at periods of time separated by a span of 27 years. The data utilized were obtained over a specific area in the central Pacific (10°N-10°S, 130°W-180°W) and a “near-global” area of the planet (60°N-60°S). The data were further constrained by masking out land/island areas and areas believed to contain clouds.
The results of their analysis showed a number of differences in the land-masked and cloud-cleared data, which the authors attributed to changes in atmospheric concentrations of CH4, CO2, O3, CFC-11 and CFC-12 that occurred over the 27-year period separating the times of their two sets of measurements. Hence, they concluded their results provided “direct experimental evidence for a significant increase in the earth’s greenhouse effect” over the 27-year time interval. Such a conclusion, however, is somewhat misleading, for it does not provide direct experimental evidence for a significant increase in earth’s total greenhouse effect. It does so only for the cloud-free part of the atmosphere located over a portion of the planet’s oceans. Furthermore, research that has been conducted on the cloudy portion of the atmosphere over the oceans has revealed the presence of a highly negative feedback phenomenon that is capable of totally overpowering any temperature increase forced by the rise in greenhouse gases.
Furthermore, the attribution of cause is without supporting evidence. This is interpretation bias. Another review explains interpretation bias and cites other studies which show why the Harries conclusion is unjustified.
3. Wang, K., and S. Liang (2009), Global atmospheric downward longwave radiation over land surface under all-sky conditions from 1973 to 2008, J. Geophys. Res., 114, D19101, doi:10.1029/2009JD011800.
These researchers estimated the downward longwave radiation over land for the period 1973 to 2008. The concluding sentence from their abstract: “The rising trend results from increases in air temperature, atmospheric water vapor, and CO2 concentration.” What did they expect? When the surface warms from any cause, we should expect these results. The results still provide no evidence on the significance of carbon dioxide emissions.
4. Evans, W.F.J. and Puckrin, E., 2009, Measurements of the Radiative Surface Forcing of Climate, JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 114, D17107, 14 PP., 2009 doi:10.1029/2009JD012105.
The introduction says that these researchers used infrared spectrometers to measure the individual radiative flux of “a number of greenhouse gases”: CFCs, methane, nitrous oxide, carbon monoxide, carbon tetrachloride, nitrous oxide, and tropospheric ozone. Carbon dioxide is not mentioned, but they do show carbon dioxide in some tables. To obtain the greenhouse flux of individual gases, they used a simulation of the atmosphere. The researchers say that the total greenhouse radiation (excluding water vapor) has increased by 3.5 watts per square meter since pre-industrial times. They also say that the radiation from water vapor has doubled to over 200 watts per square meter. These data suggest that other than water vapor, other greenhouse gases in totality are minor players.
Dr. Roy Spencer, a NASA scientist, explains in a blog why measurements such as those obtained by Evans do not really show what they are claimed to show.
5. Murphy, D.M., et al., 2009, An observationally based energy balance for the Earth since 1950, JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 114, D17107, 14 PP., 2009, doi:10.1029/2009JD012105.
This paper deals with the authors’ estimate of earth’s energy balance and the assumed forcings and feedbacks of atmospheric components. The Spencer comments above and in this article apply. This paper provides no physical evidence that carbon dioxide has a significant effect on temperatures.
The bottom line here is that Mr. Weiss could not provide unequivocal evidence to support the thesis. A point not addressed by any of the papers which mentioned some effect of carbon dioxide is that human emissions of carbon dioxide make up less than 5% of the total amount in the atmosphere. This makes the claim that human emissions are causing warming even more spurious. Much of science is speculation which investigates the what-ifs, but so is science fiction.