LAST week delivered for the global warming debate, the most anticipated data point of the decade. The year 2014 was declared the hottest of the past century, by a margin of 0.04 degC. The news has been greeted with enthusiasm by those who attribute all warming to man-made influences, (notably in the Fairfax press in Australia), but few commentators have qualified their comment with the observation that NASA put an error margin of +-0.05 C on their result.‘Angry summer’ alarmists all choked up without reading fine print
The figure below shows global surface temperature as compiled by NASA for the past 134 years. Single data points (years) are unimportant. The 5-year moving average in red is a more useful indicator of temperature trends, and its slope shows clearly the steady rising trend from 1980 to 2000, and the temperature pause from 2000 to present. Anyone with a high-school science education can look at such a graph and form their own conclusions, but four of the most important are that
• The slope of the rise from 1980 to 2000 is about 0.19 degC per decade (the rate consistent with current warming models for “business as usual” CO2 emissions)
• A closely similar rate of rise in global temperature occurred from 1910 to 1940, pre-dating current high CO2 emissions
• Pauses in the rate of rise occurred from 1880 to 1910, from 1940 to 1970, and from 2000 to present.
• The model trend as computed by the IPCC continues upwards from 2000, but the pause is a clear break of observed earth behaviour away from the models.
The pauses are regarded by the majority of scientists (both within and outside the conventional anthropogenic global warming camps) as being attributable to natural cycles in global climate, although the two groups favour different causative mechanisms.
What is surprising is that, instead of reading the multiple patterns in such a graph, enormous global publicity has followed on that single point of 2014 — even though we won’t know for a decade whether it represents a break from the current “pause” trend. Thus John Connor, CEO of The Climate Institute, greeted the 2014 result with the comment “This data shows not only a series of alarming years but decades of warming to make an undisputable trend”, which suggests a lack of awareness on his part of the steep warming trend which occurred from 1910-1940 without significant man-made assistance, and the pause from 2000 which occurred despite current CO2 emissions. Will Steffen of the Climate Council also finds cause for alarm in the 2014 data point, using the occasion to release a document titled “Off the charts: 2014 was the world’s hottest year on record” in which objective graphical analysis as we teach in high schools is replaced with poetic subheadings personifying the climate as “Angry Summer”, Abnormal Autumn” and “Scorching Spring”.
We can also look back to 2007 for a fascinating morsel of history; the figure shows at that year there is a clear hint of the start of the pause, although not statistically significant at that time. When Bob Carter, a former head of the Department of Earth Sciences at James Cook University, called attention to the discrepancy between the change temperature trend versus the modelling predictions, Andrew Ash (then acting director of the CSIRO Climate Adaption Flagship), stated “Professor Bob Carter claims that ‘no ground-based warming has occurred since 1998’. This is an unethical misrepresentation of the facts”. I suggest this is an incredible accusation to make against a scientist who has read (correctly, as history shows) a trend in a global temperature data set. When comparing Carter’s observation with pronouncements prompted by the single 2014 warm temperature point, we see a disturbing double standard in how scientific commentary is received. (In defence of the management of CSIRO I note that CSIRO has not issued a media release related to the 2014 temperature data point).
Some climate scientists will counter my views with claims that 21st century temperatures are cause for great concern because they are “the hottest ever”. Multiple lines of geological and historical data show they are not. Observations of past surface temperatures constructed from chemical composition of clam shells as far apart as Iceland and the south China Sea point to global temperatures of medieval times (800-1300AD) being warmer than those of today, and those of Roman times even warmer. The message is, the Earth can and does cool and warm on time scales of decades to millennia, and CO2 emissions are not the dominant driver. Our grandchildren will be best served if we devote our Direct Action strategies towards robust protection of communities from effects of drought, fire and floods. All have been a part of our history. And history guarantees all will be a part of our future.
Michael Asten is a professor of geophysics at Monash University, Melbourne.
How many times must the alarmists be told of the Earth's climatic history?
(1) The Mediaeval Warm Period, the Roman Warm Period, the Minoan Warm Period were warmer than the current warming and occurred BEFORE the industrial revolution without high concentrations of carbon dioxide in the atmosphere. This is natural variability at work.
(2) Vostok ice core data relating to deglaciations reveals that temperature increases occurred some 8 centuries or more BEFORE the corresponding increases in atmospheric carbon dioxide concentrations. Similarly, a recent study (by Zhiaou & Feng) of Antarctic ice core data covering the last 10,000 years ALSO showed that temperature increases occurred BEFORE the atmospheric concentration of carbon dioxide increased. The temporal relationship is presumably due to delayed outgassing from the oceans which contain some 50 times as much carbon dioxide as the atmosphere.
NOTE to the alarmists: causes do NOT occur after their effects.
(3) Other studies of temperature vs atmospheric carbon dioxide concentration on geological time scales show absolutely NO CORRELATION between temperature and atmospheric carbon dioxide concentration. There are extended periods in the past in which these two variables head in opposite directions viz. temperature going down while CO2 is going up and vice versa.
(4) Studies have shown that the Earth's atmospheric carbon dioxide concentration has been as high as 30% (compared with the current 0.04%) and yet the 'runaway greenhouse effect' did NOT occur otherwise we would not be here to discuss it.
(5) the alarmists are fond of quoting Venus as the exemplar of the runaway greenhouse effect. The fact is that water vapour is the dominant greenhouse gas and when Venus had water the surface temperature and atmospheric pressure there were at least 3 times what they are currently. (See 'An Introduction to Astrophysics' by Carroll & Ostlie).
(6) None of the computer models of climate (so vaunted by the alarmists) have been validated by real world observations and they have consistently predicted/projected temperatures higher than subsequently observed.
(7) The alleged 'fingerprint' of greenhouse gas induced warming of our planet (according to the IPCC's models) was supposedly a 'hot spot', warming more rapidly, in the atmosphere 10km above the tropics. No such 'hot spot' was ever found by the satellite data.
(8) "The science is settled" claim is patently false - there are still so many uncertainties about the physics of clouds, aerosols, ocean circulation etc. that it is no wonder the IPCC computer models have no skill and have not been validated.
There is much more but a line must be drawn somewhere.