The Australian continues to display its contempt for science, scientists and the scientific method. They’ve published this piece of AGW denial by David Evans. Last time I looked at Evans he was saying that new evidence since 1999 had changed his mind about global warming, with this new evidence including the fact that the world had cooled from 1940 to 1975. Apparently this was too silly even for the Australian, so he now offers us four alleged facts.
1 The greenhouse signature is missing. We have been looking and measuring for years, and cannot find it.
Each possible cause of global warming has a different pattern of where in the planet the warming occurs first and the most. The signature of an increased greenhouse effect is a hot spot about 10km up in the atmosphere over the tropics.
This couldn’t be more wrong. Study the graphs below (from RealClimate). The left one shows the pattern predicted for doubling CO2, while the right one shows the pattern for a 2% increase in solar output.
Both patterns include a hot spot. The difference between the two graphs is that the CO2 one shows cooling in the stratosphere, while the right one does not, so the “greenhouse signature” is stratospheric cooling. And guess what, that’s what’s been happening. Evans continues:
We have been measuring the atmosphere for decades using radiosondes: weather balloons with thermometers that radio back the temperature as the balloon ascends through the atmosphere. They show no hot spot. Whatsoever.
If there is no hot spot then an increased greenhouse effect is not the cause of global warming. So we know for sure that carbon emissions are not a significant cause of the global warming. If we had found the greenhouse signature then I would be an alarmist again.
Actually we have found the greenhouse signature, so Evans should change his mind. I’m not holding my breath.
If the hot spot really is missing it does not prove that CO2 is not causing warming, but it would indicate something wrong with the models. (Which might mean that things are worse than what the models predict.) However, the radiosonde measurements have been found to be wrong in the past, and it looks like they may well be wrong again.
2 There is no evidence to support the idea that carbon emissions cause significant global warming. None. There is plenty of evidence that global warming has occurred, and theory suggests that carbon emissions should raise temperatures (though by how much is hotly disputed) but there are no observations by anyone that implicate carbon emissions as a significant cause of the recent global warming.
This is pure denial. There is plenty of evidence and denying that it exists does not make it disappear. For instance, Figure 4 of the SPM. The blue bands show temperature changes modelled using only natural forcings, while the red bands include anthropogenic forcings as well. The black line shows observations. Clearly, we must include anthropogenic forcings if we want to match the observations.
3 The satellites that measure the world’s temperature all say that the warming trend ended in 2001, and that the temperature has dropped about 0.6C in the past year (to the temperature of 1980).
Let’s look at the lower troposphere trends from RSS:
Figure 7. Global, monthly time series of brightness temperature anomaly for channels TLT, TMT, TTS, and TLS. For Channel TLT (Lower Troposphere) and Channel TMT (Middle Troposphere), the anomaly time series is dominated by ENSO events and slow tropospheric warming.
The people who publish the data don’t think that the warming trend ended in 2001, and if you look at the graph, it’s only significantly deviated from the long term warming trend in 2008. Such short-term deviations have happened in the past without affecting the long term trend.
Land-based temperature readings are corrupted by the “urban heat island” effect: urban areas encroaching on thermometer stations warm the micro-climate around the thermometer, due to vegetation changes, concrete, cars, houses. Satellite data is the only temperature data we can trust, but it only goes back to 1979.
The land-based temperature readings are corrected for UHI, while the satellite readings have been found to be wrong in the past.
NASA reports only land-based data, and reports a modest warming trend and recent cooling. The other three global temperature records use a mix of satellite and land measurements, or satellite only, and they all show no warming since 2001 and a recent cooling.
Study the title of the NASA temperature graph:
Does it report only land-based data, or does it include ocean temperatures as well?
4 The new ice cores show that in the past six global warmings over the past half a million years, the temperature rises occurred on average 800 years before the accompanying rise in atmospheric carbon. Which says something important about which was cause and which was effect.
This is wrong. The temperature rises started on average 800 years before CO2 levels rose, but most of the warming occured after CO2 levels started rising. Jeff Severinghaus writes:
Does this prove that CO2 doesn’t cause global warming? The answer is no.
The reason has to do with the fact that the warmings take about 5000 years to be complete. The lag is only 800 years. All that the lag shows is that CO2 did not cause the first 800 years of warming, out of the 5000 year trend. The other 4200 years of warming could in fact have been caused by CO2, as far as we can tell from this ice core data. …
In other words, CO2 does not initiate the warmings, but acts as an amplifier once they are underway. From model estimates, CO2 (along with other greenhouse gases CH4 and N2O) causes about half of the full glacial-to-interglacial warming.
That’s it for all of Evans’ evidence. The rest of his article is more pure denial. For instance:
If there really was any evidence that carbon emissions caused global warming, don’t you think we would have heard all about it ad nauseam by now?
He has, but he just denies that it is evidence.