My attention was caught today by a fascinating article (below) about the ever-present issue of climate change. As a sceptic by nature, and as someone presently surrounded by nearly 2 foot of drifting snow outside my door, I am hearing all too clearly the weathermen on the radio telling me that this is the coldest November on record, that temperatures in the North East are colder than at the North Pole, and that this "cold snap" is due to last for a fortnight.
With all these thoughts at the front of my mind, this article by Research Professor Bob Carter, from James Cook University (Queensland), palaeontologist, stratigrapher, marine geologist and environmental scientist, has captured my interest.
"An alternative view has emerged regarding the most cost-effective way in which to deal with the undoubted hazards of climate change. This view points towards setting a policy of preparation for, and adaptation to, change as it occurs, which is distinctly different from the emphasis given by most western parliaments to the mitigation of global warming by curbing carbon dioxide emissions. Ultimately, the rationale for choosing between policies of mitigation or adaptation must lie with an analysis of the underlying scientific evidence about climate change.
The vigorous public debate over possibly dangerous human-caused global warming is bedevilled by two things. First, an inadequacy of the historical temperature measurements that are used to reconstruct the average global temperature statistic. And second, fuelled by lobbyists and media interests, an unfortunate tribal emotionalism that has arisen between groups of persons who are depicted as either climate “alarmists” or climate “deniers”. In reality, the great majority of scientists fit into neither of these categories, but rather hold balanced and non-extreme views about the complex issue of climate change.
In this context, all competent scientists accept (i) that global climate has always changed, and always will; (ii) that human activities (not just carbon dioxide emissions) definitely affect local climate, and have the potential, summed, to measurably affect global climate; and (iii) that carbon dioxide is a mild greenhouse gas. The true scientific debate, then, is about none of these issues, but rather about the sign and magnitude of any global human effect, and its likely significance when considered in the context of natural climate change.
For many different reasons, which include various types of bias and unaccounted for artefacts, the thermometer record provides only an indicative history of average global temperature (AGT) over the last c.150 years. The 1979-2009 satellite MSU record is our only acceptably accurate estimate of AGT, yet being but 30 years in length it represents just one climate data point. The second most reliable estimate of AGT, collected by radiosondes on weather balloons, extends back to 1958, and the portion that overlaps with the MSU record matches it well. Taken together, these two records indicate that no significant warming has occurred since 1958, though both exhibit a 0.2 deg. C step increase in AGT across the strong 1998 El Nino. In addition, the currently quiet sun, and the lack of warming over the last 10 years or more, indicates that cooling may be the greatest climate hazard over the next few decades.
Climate change takes place over geological time scales of thousands through millions of years, yet unfortunately geological datasets do not provide direct measurements, least of all of AGT. Instead, they comprise local or regional proxy records of climate change of varying quality.
Nonetheless, numerous high quality palaeo-climate records, and especially those from ice cores and deep-sea mud cores, demonstrate that no unusual or untoward changes in climate occurred during the 20th and early 21st century. Despite an estimated spend of more than $100 billion since 1990 looking for a human global temperature signal, assessed against geological reality no compelling empirical evidence yet exists for a measurable, let alone worrisome, human impact on AGT.
A key issue on which all scientists agree is that natural climate-related events and change are real, and exact very real human and environmental costs. These hazards include storms, floods, droughts, bushfires, and temperature steps and longer term cooling or warming trends. It is certain that these natural climate-related events and change will continue, and that from time to time human and environmental damage will be wrought.
Extreme weather events (and their consequences) are natural disasters of similar character to earthquakes, tsunami and volcanic eruptions, in that in our present state of knowledge they can neither be predicted far ahead nor prevented once underway. The matter of dealing with future climate change, therefore, is primarily one of risk appraisal and minimization, and that for natural risks which vary from place to place around the globe.
The difficulties encountered around the world in implementing carbon dioxide trading or taxation partly reflects that such mechanisms are able to be depicted as expensive, disruptive and ineffectual – and that even should warming soon resume, let alone if cooling occurs. Carbon dioxide reduction is therefore neither an adequate national climate policy nor necessarily even a desirable part of one. Climate change as a natural hazard is as much a geological as it is a meteorological issue. Thus it needs to be managed in the same way as other geohazards, i.e., by monitoring for the onset of dangerous events and by having a civil defense response plan to deal with events as and when they happen.
Policymakers need to abandon the illusory goal of “preventing global warming” by reducing carbon dioxide emissions. Instead, dealing with climate reality as it unfolds represents the most prudent, practical and cost-effective solution to the global warming/climate change issue. Such a policy of adaptation is also strongly precautionary against any possibly dangerous, human-caused climate trends that might emerge in future."
