CLIMATE CONFERENCE IN HALIFAX, NOVA SCOTIA
"First International Conference On Global Warming And The Next Ice Age"

An unusual conference at Dalhousie University [20 to 24 August, 2001] brought together a large number of so-called skeptics and supporters of manmade climate change. About 100 scientists attended. In simplified terms, it pitted those who view climate data as important against modelers who believe that models should get the major emphasis. While the conference did not resolve any of the crucial issues, it did serve to define areas of agreement and contention.

Here follows an idiosyncratic summary of the conference. From where I stand, there are three basic areas in climate science that need to be resolved by further research and critical discussions:

1. Is the climate currently warming?
2. What causes observed climate variations?
3. Can climate models account for observations?

A separate issue discussed at the conference related to the next ice age, its timing and its mode of initiation.

1. Is the climate currently warming?

John Christy [University of Alabama, Huntsville] reviewed global weather satellite observations that show no warming trend in the troposphere during the last 22 years. It should be noted that climate models all predict that the troposphere should warm more rapidly than the surface

The major discrepancy with surface data occurs in the tropical zone. Christy mentioned the puzzling observation that sea-surface temperature and marine air temperature show different trends, throwing doubt on the reliability of the SST results. This issue was not resolved and needs to be addressed in more detail.

Fred Singer [University of Virginia and SEPP] concentrated his discussion on proxy data. Tree rings, ice cores, corals, etc. show no appreciable warming since about 1940 and are in good support of the results from satellites. The data cover a wide geographic range so that one can argue with some justification that the global climate has not warmed in the last sixty years. This of course is in direct contradiction to results from climate models.

Singer also discussed the phenomena of deep-ocean warming, shrinking of Arctic sea ice and glaciers, and rising sea levels. All of these have been blamed on human activities. Singer showed that they can be fully explained in terms of the delayed effects of previous, naturally caused warming. He predicted that sea level would continue to rise at the same rate as in past centuries, irrespective of human activities. This evoked much discussion and some disagreement on Arctic sea ice and glaciers. The question there was whether their shrinkage is stabilizing or would continue into the future.

2. What causes observed climate variations?

Most discussion of natural changes of climate is in terms of various [internally controlled] atmosphere-ocean interactions, like El Nino, North Atlantic Oscillation, the Arctic Oscillation, the Pacific Decadal Oscillation, etc. But proponents of [external] solar controls on climate dominated the conference. The question left unanswered was whether solar changes could cause the atmosphere-ocean oscillations as primary effects.

Paal Brekke, Theodor Landscheidt, and Paul Damon gave extensive discussions of solar variability and showed connections between solar cycles and climate fluctuations. I found particularly compelling the detailed correlations between Carbon-14 [a proxy for cosmic rays and therefore solar activity] and Oxygen-18, observed in a stalagmite in a cave in Oman over a period of 3,000 years. [See the appended graph.] Unfortunately, there's no agreement yet on the physical mechanism that could link cosmic rays to climate changes: indeed, cosmic rays may not even be the primary influence on the atmosphere.

Ref: U. Neff et al. Strong coherence between solar variability and the monsoon in Oman between 9 and 6 kyr ago. Nature 411, 290-293, 17 May 2001.

3. Can climate models account for observations?

Unfortunately, modelers were not well represented, so we did not get the exposure to the GISS model or the Hadley model. But Tony Broccoli [GFDL, NOAA] did an excellent job of presenting the latest results from GFDL, Princeton. Successive runs introduced additional forcing, starting with pure greenhouse, then adding the direct effects of sulfate aerosols [in the form of surface albedo changes], changes in solar irradiance [Lean], and volcanic eruptions [Andronova, 1999]. This last run showed a surprisingly low warming trend of only 0.03 degrees per decade.

However, in discussion it was brought out that the models did not include the indirect aerosol effects [on cloudiness, as discussed by Grassl, which are larger than the direct effects], changes in stratospheric ozone, and the more important solar influences from solar wind and magnetic field changes.

Bill Gray [Colo. State University] pointed to a major deficiency of all current models that cannot handle the (possibly negative) water-vapor (WV) feedback produced by drying of the upper troposphere (UT). Gray favors a feedback mechanism that concentrates intensive cumulus activity into a smaller area with larger regions of subsidence that remove UTWV.

There is also need to standardize the various radiative forcing effects so as to facilitate intercomparison between models. Finally, it is important to validate the models with observations not only on a global scale but also for each hemisphere separately since some of the forcing [e.g., aerosol effects] is geographically specific.

4. The next ice age

Using orbital theory calculations, Andre Berger [University of Louvain, Belgium] demonstrated that the current interglacial period [Holocene] could last another 40,000 years, a result not widely known. Based on a climate model developed at his institute, he claimed that if carbon dioxide reaches levels of more than 750 ppm, it might be sufficient to melt all of the terrestrial ice.

George Kukla [Lamont Geophysical Observatory], by analogy with the most recent [Eemian] glaciation, which took place 115,000 years ago, predicted that El Nino events would warm the equatorial zone supplying the moisture necessary to develop ice buildup at high Northern latitudes, triggering the next ice age.

Finally, Richard Peltier [Univ. of Toronto] showed that initiation of the glaciation process is extremely sensitive to greenhouse forcing. He calculated that the most recent [Eemian] glaciation would have been suppressed if the CO2 content had gone from 280 to 365 ppm.

Conclusion:

With climate showing little if any current warming, it suggests that natural variability is masking the enhanced (anthropogenic) greenhouse effect. Natural variability on a decadal-to-century time scale seems to be caused by the large variability in solar activity, as shown by cosmic ray variability. Climate models are grossly overestimating the human influence, probably because the models are not handling negative feedbacks properly.