Bob Brown, leader of the Australian Greens, speaking from his sea-front office in Hobart, Tasmania, said that “scientists agree that current floods come from record-high temperatures of Australian oceans this season”, and demanded that a full-scale profits-tax on “the culprits” in coal mining should be imposed, with half set aside for future natural catastrophes in Australia, because “burning coal is a major cause of ‘global warming’” and, “as well, 700,000 seaside properties in Australia face rising sea levels”.
Scientists agree that the Brisbane floods are a consequence of the unusually severe la Niña phase of the el Niño Southern Oscillation, a naturally-occurring four-year cycle of warming and cooling of the world’s oceans, starting in the equatorial eastern Pacific and carried around the globe by the thermohaline circulation of ocean currents.
Scientists also agree – for it is a matter of record – that floods of similar severity have struck the east coast of Australia before: twice in the 19th century and most recently in 1974. These earlier floods could not have been caused by manmade “global warming”, because there was not enough of it to make any difference at that time.
Furthermore, scientists from the UN Intergovernmental Panel on Climate Change agree that it is not possible to ascribe individual severe-weather events to “global warming”. They have said so twice: in the 2001 Third Assessment Report and in the 2007 Fourth and most recent Assessment Report.
Indeed, at present it is impossible to ascribe anything to “global warming”, for the good and sufficient reason that there has been hardly any for a decade. Indeed, even after the influence of the recent severe el Niño, whose effects on the climate persisted for more than nine months, the rate of “global warming” in the first decade of the 21st century was actually lower than the warming rate observed in the 20th century.
Nor is burning coal a “major cause of ‘global warming’”, not only because there has been remarkably little “global warming” in the past decade but also because electricity generation accounts for just 40% of global carbon emissions, and coal represents about 75% of that, or 30% of carbon emissions.
Scientists also agree – for it is a matter of record – that floods of similar severity have struck the east coast of Australia before: twice in the 19th century and most recently in 1974.At present it is impossible to ascribe anything to “global warming”, for the good and sufficient reason that there has been hardly any for a decade.
Even if we continued to burn coal worldwide at the present rate (which is quite possible, because hundreds of years’ supply is available), and even if we believed the IPCC’s increasingly-obvious overstatement to the effect that a doubling of atmospheric CO2 concentration is likely to cause 3 Celsius degrees of “global warming”, coal burning would be responsible for only 1 Celsius – and even that figure is for equilibrium warming, which will not occur for 1000 years.
In this century, the IPCC expects only 57% of eventual equilibrium warming to occur, with the remainder spread out over 1000 years of very slowly rising temperatures. So coal’s contribution to 20th-century warming, even if the IPCC is right about CO2’s warming effect, will be little more than half a Celsius degree. If the IPCC has exaggerated climate sensitivity by several hundred percent, as a growing body of scientific literature and real-world data suggest, then coal’s contribution to warming will be even less than that – and the overall warming will be too little to worry about anyway.
Even if the warming were as big as the IPCC imagines, it would not be as dangerous as Mr. Brown suggests. After all, recent research suggests that some 9,100 of the past 10,500 years were warmer than the present by up to 3 Celsius degrees: yet here we all are.
Finally, if Mr. Brown genuinely believes that sea-level rise will imminently threaten 700,000 Australian seaside properties, perhaps he would care to explain to his voters why it is that his own office is at the Harbourside in Hobart, just feet from the ocean that he alleges is rising so dangerously? Or could it be that he realizes that Professor Niklas Mörner is right when he says that 1 ft/century is just about the maximum sea-level rise that is physically possible in present conditions – and it is less than a quarter of the mean centennial sea-level rise over the past 11,400 years.
The ocean is not rising dangerously, of course. Ever since accurate global sea-level measurements were first made by satellite altimetry against a reference geoid in 1993, sea level has been rising at around 1 foot per century – much as it had throughout the past 150 years, when attempts had been made to compile a global sea-level record from tide-gauges.
See also: http://scienceandpublicpolicy.org/images/stories/papers/originals/southpacific.pdf.