“Today’s debate about global warming is essentially a debate about freedom. The environmentalists would like to mastermind each and every possible (and impossible) aspect of our lives.”
Blue Planet in Green Shackles
October 17, 2012
Over the past three decades energy policy has increasingly become determined by public concern about the impact of anthropogenic carbon dioxide emissions on future climate. The message that has received wide coverage is that increasing atmospheric carbon dioxide will lead to a significant increase in global temperature. The alleged danger is that the climate system might pass a tipping point and there will be irreversible climate change.
The message is not new and has its origins in the evolution of understanding of the climate system over the 19th and 20th centuries.
A 2005 paper that succinctly alerts to the rudimentary status of understanding of the climate system, titled ‘The Gap between Simulation and Understanding in Climate Modeling’, was published in the Bulletin of the American Meteorological Society by Isaac Held of the US Geophysical Fluid Dynamics Laboratory. Two quotes will suffice:
Due to the great practical value of simulations, and the opportunities provided by the continuing increases in computational power, the importance of understanding is occasionally questioned. What does it mean, after all, to understand a system as complex as the climate, when we cannot fully understand idealized nonlinear systems with only a few degrees of freedom?
Despite several major observational campaigns designed to guide us toward appropriate closures for deep, moist convection, little consensus exists as to the best formulations for climate models.
Clouds are an integral component of the climate system in that they directly reflect incoming solar radiation back to space. They also interact with the earth’s radiation fields even more than the greenhouse gases. Errors in specification of clouds and their interactions lead directly to errors in projection of future climate state. Held concludes:
The health of climate theory/modeling in the coming decades is threatened by a growing gap between high-end simulations and idealized theoretical work.
The uncertainty of climate projections is underscored when we recognise the relationship between the atmospheric and ocean fluids. The mass of the atmosphere is equivalent to 10 metres of ocean depth; the thermal capacity of the atmosphere is equivalent to about 3.5 metres of the ocean depth. The mixed layer where surface winds stir the ocean surface is only about 250 metres thick. The average depth of the oceans is about 4,000 metres. Clearly the oceans are the thermal and inertial flywheels of the climate system.
The primacy of the oceans is demonstrated by changing upwelling across the equatorial Pacific Ocean during El Niño and La Niña events. Between these events the average global surface temperature can vary by about 1oC. Our understanding of changing ocean circulations and their impacts on climate over the decadal to century timeframe is limited because systematic observations of sub-surface ocean circulations only commenced with the deployment of ARGOS buoys in the last decade.
The global temperature change over the past three decades highlights the divergence between climate model projections and reality. Carbon dioxide has been systematically increasing over this time and climate models have consistently projected rates of temperature rise that should have seen warming over the period of between 0.6oC and 1.5oC, with a most likely value near 0.9oC. The actual temperature rise since 1980 has been about 0.3oC, or only half the minimum warming projected.
There are a number of reputable scientists who have independently used real-world data with statistical relationships and methods derived from basic physics to address the question of climate sensitivity. Many of these assessments suggest a sensitivity that is below 1oC for a doubling of carbon dioxide, much less than the computer model projections.
If we look behind the carefully packaged and promulgated official assessments of the sensitivity of climate to carbon dioxide we find a range of assumptions, assertions and approximations. There are many uncertainties and unknowns about the climate system and its future state. In its 1990 first assessment report the IPCC honestly concluded in the scientific assessment:
That statement is as true today as it was in 1990. Recent global temperature trends strongly suggest that the climate sensitivity is far less than the projections from computer models would have us believe, projections on which governments rely in the formulation of energy policy.
The availability and cost of energy are fundamental to the competitiveness of our industries and the lifestyles we enjoy. The Precautionary Principle may have once been justification for government intervention in energy policy but it is now time to reassess those interventions. The divergence between climate projections and reality suggest that the national and regional energy mix should not be constrained by climate considerations. Models that only approximately represent the climate system and for which there remains many knowledge gaps are proving misleading and inadequate as a basis for energy policy.
William Kininmonth is a consulting climatologist who worked with the Australian Bureau of Meteorology for 38 years in weather forecasting, research and applied studies. For 12 years, until 1998, he was head of its National Climate Centre. Between 1998 and 2002, he consulted to the World Meteorological Organization, including coordinating an international review of the 1997-98 El Niño event and preparation of a WMO publication, Climate into the 21st Century (Cambridge). He is author of Climate Change: A Natural Hazard (Multi-Science Publishing).
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