By Godfrey Bloom
The Intergovernmental Panel on Climate Change (IPCC) has released the first part of its fifth assessment report (AR5) - the Summary for Policymakers (SPM). Much is being made by pundits, politicians and activists about the summary's increased estimate of confidence in climate science. But the upgrading of confidence from '90%' to '95%' belies the SPM's actual content.
'Ninty-five per cent' is a wholly meaningless statement of confidence. It is not an empirical measure of anything tangible. It's not even a poll of the scientists. Such is its ambiguity, it could even be a statement that scientists are more sure of less warming. And its intended audience don't seem to know what it means. Note that the statement of confidence relates only to the human contribution to warming since 1950, not to any of the consequences of that warming. But pundits and politicians have already tried to link the '95%' to catastrophic consequences such as extreme weather. In fact the IPCC agree that there has been no observable increase in storm intensity, frequency or longevity, droughts or floods, in spite of global warming.
Politicians being simple folk, they do not seem to understand that there is a difference between global warming, climate change and their consequences. There is evidence of global warming. There is significantly less evidence of climate change. There is less than zero evidence of negative consequences of climate change: people are wealthier, healthier, and better protected from nature than at any point in human history -- because of wealth, not the climate.
Where is the warming? What happened to the pause in global warming?
Sceptics have pointed out that the SPM has hidden problems in climate science. The biggest problem is the fact of non-warming since the late 1990s -- a fact almost completely ignored by the report. This fatal omission will lead to questions about the credibility of the IPCC report from sceptic and non-sceptic perspectives alike. The entire climate science community has been talking about the non-warming since climategate revealed that world-leading climate scientists knew that there was no warming, and that it was in one scientists words "a travesty that we cannot explain it".
That scientist has since argued that the extra warming has not gone to the surface of the planet, but has made its way undetected through the atmosphere, to warm the deep oceans. That hypothesis is the argument now advanced by environmental activists, but it is highly controversial and forms no part of the scientific consensus. It suffers from two main problems.
First, there is no reliable observational evidence to support the ocean warming hypothesis. The data produced by proponents of the hypothesis suggests a rate of ocean warming of two-thousandths of a degree per year. Measurements of such a tiny effect require a level of accuracy that most modern thermometers are not capable of, let alone thermometers made of mercury and glass and read by eye. Then there are the problems of analysing the data from these thermometers -- removing a minute (and possibly non-existent) signal from a great deal of noise. And then there is the problem of resolution: just one of the thermometers that produced the data sits alone in thousands of cubic kilometres of water. It's not unlike trying to read small print on a postage stamp, from a distance of half a mile, with the naked eye, in the dark.
Second, previous estimates of climate change presented to policy-makers have emphasised surface temperatures, not ocean temperatures. The attempt to emphasise ocean, rather than surface temperatures is a case of changing the evidence to suit the political narrative.
This shifting of the goalposts, and the omission of the warming pause from the SPM aren't enough to say that global warming is not happening. But what they do reveal is that advocates of climate policies have had to twist the science and evidence to sustain the story of a warming planet. We can only be certain that climate science is not stronger and that we now know that models and projections of global warming have exaggerated the likely effect of CO2 in the atmosphere.
How much warming will there be?
The IPCC report examines a range of plausible scenarios to estimate how much warmer the world will be in the future. The previous IPCC report, estimated a range of two to 4.5 degrees warming by 2100. The current report broadens the range of likely temperatures, to encompass the possibility of a lower rate of warming: 1.5 degrees.
This reflects that fact that the observational record shows temperatures beneath those projected by previous IPCC report. Almost every model used to simulate the future effect of CO2 on the planet have been shown to significantly over-estimate warming. The IPCC's record of predicting temperatures isn't just poor, it is consistently wrong. According to Bjorn Lomborg, the IPCC overestimates warming by between 71% and 159%. In their own way, the IPCC have admitted in the SPM that this disparity between models and observations makes producing a consensus on how much warming there will be impossible.
Yet pundits and politicians are claiming that the report shows 'unequivocally' that the planet is committed to a temperature regime that will exceed the two degree limit of 'dangerous climate change' this century. This is not true. The IPCC clearly states otherwise.
The two degree target should be understood as a political target, not a limit that has been identified by science. There is no mechanism triggered by a temperature rise of two degrees. The only logic to the target is that if such a mechanism did exist, you could be more sure of it existing at two2 degrees than one. But this is true of any figure The two degree limit is arbitrary and at best a truism.
How much sea level rise will there be?
The new report has narrowed the likely range of sea level rise, but moved the range upwards. The minimum sea level rise is now stated as 26cm (up from 18cm in AR4), and the maximum is 98cm.
However, this should be seen in the context of claims about sea level rise from the alarmist camp, who claimed that the previous report was too conservative. There have been many investigations into sea level rise, but they have not supported the alarmist cause, and have consistently found in favour of the lower estimates. Al Gore and James Hansen, for example, spoke of many metres of sea level rise, and an imminent possibility of widespread coastal flooding. The IPCC rejects these claims, yet it is the Hansen/Gore line that politicians and activists have most responded to.
Whatever the rate of sea level rise (and climate change), it is a problem that the world faced, whether temperatures were increasing or not. Sea level rise is associated with the transition from large and mini-ice ages.
Does the IPCC report support the alarmist case?
International, EU and domestic climate and energy policies have been premised on the avoidance of worst-case scenarios, not the most likely scenarios. And even the most likely scenarios have been over-stated by previous IPCC reports. There are good reasons to believe that the IPCC has not overcome the problems of climate science, and therefore it continues to overstate the likely impacts of climate change.
However, the projections offered by the IPCC do not support the alarmist story of climate extremes this century. In fact, the sober view of the evidence relating to the consequences of climate change is that it will not be possible to detect any climate change signal in weather events this century. Even if climate change is real, and assuming a significant influence of global warming on climate systems, it may be centuries before it is possible to identify a link between climate change and extreme weather.
We have been promised wildfires, drought, mega storms, pandemics and plagues, mass extinctions, wars, famine, biblical levels of rain, a breakdown of society and economic ruin. These are generally the (failed) prophecies of politicians and green activists, rather than the IPCC. But the IPCC itself does seem to have consistently over-estimated warming and its consequences, and it has been extremely quiet in the face of such claims and about its own errors and inadequacies. The IPCC sells a political story -- confidence in the ability to predict the future -- to politicians. Until this is understood, climate change alarmism will continue to run wild and unchecked through the corridors of power.
Godfrey Bloom is an independent member of the European Parliament for Yorkshire and the Humber
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