Wednesday, March 23, 2016

The fifth and last step - drowning!

Yes, there is fossil fuel carbon dioxide building up in the air; it might be contributing to the warming of the world; it is almost certainly not wishing wild weather upon us; so there remains the last question - will the seas rise and submerge huge swathes of real estate?

First it needs to be recognized that the sea level is rising. It has been rising for about the past 25 000 years. However, for the past 7 millennia it has been rising slower than ever before:

The critical question, however, is whether the observed slow rate of rise has increased as a result of the warming climate. There are several lines of evidence that it has not.  One is the long-term data from tide gauges. These have to be treated with caution because there are areas where the land is sinking (such as the Gulf of Mexico, where the silt carried down the Mississippi is weighing down the crust), and others where it is rising (such as much of Scandinavia, relieved of a burden of a few thousand metres of ice about 10 000 years ago). A typical long-term tide gauge record is:

The 1860-1950 trend was 2.47-3.17mm/a; the 1950-2014 trend was 2.80-3.42mm/a, both at a 95% confidence level. The two trends are statistically indistinguishable. There is <5% probability that they might show any acceleration after 1950.

Another line of evidence comes from satellite measurements of sea level.  The figure below shows the latest available satellite information – it only extends back until 1993. Nevertheless, the 3.3±0.3mm/a rise in sea level is entirely consistent with the tide gauge record:

Thus several lines of evidence point to the present rate of sea level rise being about 3mm/a or 30cm per century. Our existing defences against the sea have to deal with diurnal tidal changes of several metres, and low-pressure-induced storm surges of several metres more.  The average height of our defences above mean sea level is about 7m, so adding 0.3m in the next century will reduce the number of waves that occasionally overtop the barrier.

The IPCC predicts (using its rather suspect models) that the sea level will rise by between 0.4 and 0.7m during this century. It claims:
"It is very likely that the mean rate of global averaged sea level rise was 1.7 [1.5 to 1.9] mm/yr between 1901 and 2010 and 3.2 [2.8 to 3.6] mm/yr between 1993 and 2010"
There are many tide gauges where the land does not appear to rising or falling. They all show a change in sea level the region of 2.5-2.9mm/a over the 20th century. On the other hand there are some stations, such as Simonstown, that do indeed seem to show an acceleration in the 21st century; while, surprisingly, many tide gauges on Pacific and Indian Ocean islands show no sea-level rise at all e.g. Guam, Eniwetok, Johnston Atoll.

A very recent paper notes that there was probably a fall of the order of 0.2mm/a as the world cooled after the Medieval Warm Period, and that as we recover from the Little Ice Age (which ended about 1850) the sea has been warming and expanding and, of course, is fed by melting glaciers. They estimate the 20th century sea-level rise to have been only about 0.15m, but predict that the 21st century could see a rise of between 0.24 and 1.31m.

Given the wide range of the prediction, there is a possibility they could be right. Importantly, of course, is the fact that even a 1.3m rise is not likely to be a disaster, in the light of the fact that our defences are already metres high – adding 20% to them would be costly, to be sure, but we would have decades to make the change, and should have more than adequate warning of any significant increase in the rate of sea level rise.


Our five steps have shown:
  • the combustion of ever increasing quantities of fossil fuel has boosted the carbon dioxide concentration of the atmosphere.  
  • the impact of that increase is not demonstrable in a scientific way. There may be some warming of the atmosphere, but at present any warming is almost certainly hidden in the natural variation of temperatures. 
  • there is no evidence for any increase in the frequency or magnitude of weather phenomena, and that includes droughts and floods.  
  • there is a small possibility that sea level rise may make some real estate uninhabitable, but the rise over the coming century is not likely to present any insuperable challenge.
 It can only be concluded that our world will remain perfectly habitable in the face of rising carbon dioxide levels.

The fourth stumbling step

Thus far we have seen that carbon dioxide really is increasing in the atmosphere, and that the evidence that it originates from burning fossil fuels is good. However, in the third step, we found that the link between carbon dioxide in the atmosphere and global temperatures was tenuous at best, and certainly not at the level of understanding where anyone could say "We can control the global temperature rise to less than 2 degrees C by controlling carbon emissions!" They can't, and we will stop wasting money the sooner they realize the falsity of such a statement.

In this fourth step we examine what the climate effects of a warmer world might be.  First, what is “climate”? It is the result of averaging a climatological variable, such as rainfall or atmospheric pressure, measured typically over a month or a season, where the average is taken over several years so as to give an indication of the weather that might be expected at that month or season.

Secondly, we need to understand the meaning of “change”. In this context it clearly means that the average of a climatological variable over X number of years will differ from the same variable averaged over a different set of X years.  But it is readily observable that the weather changes from year to year, so there will be a natural variation in the climate from one period of X years to another period X years long.  One therefore needs to know how long X must be to determine the natural variability and thus to detect reliably any change in the measured climate.

This aspect of “climate change” appears to have been overlooked in all the debate about climate change.  It seems to be supposed that there was a “pre-industrial” climate, which was measured over a large number of years before industry became a significant factor in our existence, and that the climate we now observe is statistically different from that hypothetical climate.

The problem, of course, is that there is very little actual data from those pre-industrial days, so we have no means of knowing what the climate really was.  There is no baseline from which we can measure change. 

Faced by this difficulty, the proponents of climate change have modified the hypothesis. It is supposed that the observed warming of the earth will change the climate in such a way as to make extreme events more frequent. This does not alter the difficulty; in fact, it makes it worse.

To illustrate, assume that an extreme event is one that falls outside the 95% probability bounds. So in 100 years, one would expect 5 extreme events on average.  Rather than taking 100 years of data to obtain the average climate, there are now only 5 years to obtain an estimate of the average extreme event, and the relative error in averaging 5 variable events is obviously much larger than the relative error in averaging 100 variable events.

The rainfall data for England and Wales demonstrates this quite convincingly:-
The detrended data is close to normally distributed, so that it is quite reasonable to use normal statistics for this. The 5% limits are thus two standard deviations either side of the mean.  In the 250-year record, 12.5 extreme events (those outside the 95% bounds) would be expected.  In fact, there are 7 above the upper bound and 4 below the lower bound, or 11 in total. Thus it requires 250 years to get a reasonable estimate (within 12%) of just the frequency of extreme rainfall.  There is no possibility of detecting any change in this rate, as would be needed to demonstrate “climate change”.

Indeed, a human lifespan is insufficient even to detect the frequency of the extreme events.  In successive 60-year periods, there are 2, 4, 2 and 2 events, an average of 2.5 events with a standard deviation of 1.0. There is a 95% chance of seeing between 0.5 and 5.5 extreme events in 60 years, where 3 (5% of 60) are expected. Several lifetimes are necessary determine the frequency with any accuracy, and many more to determine any change in the frequency.

It is known to have been warming for at least 150 years. If warming had resulted in more extreme weather, it might have been expected that there was some evidence for an increase in extreme events over that period. The popular press certainly tries to be convincing when an apparently violent storm arises. But none of the climatological indicators that have data going back at least 100 years show any sign of an increase in frequency of extreme events

For instance, there have been many claims that tropical cyclones are increasing in their frequency and severity.  The World Meteorological Organisation reports:  “It remains uncertain whether past changes in tropical cyclone activity have exceeded the variability expected from natural causes.”

It is true that the damage from cyclones is increasing, but this is not due to more severe weather.  It is the result of there being more dwellings, and each dwelling being more valuable, than was the case 20 or more years ago.  Over a century of data was carefully analysed to reach this conclusion.  The IPCC report on extreme events agrees with this finding.

Severe weather of any kind is most unlikely to make any part of our planet uninhabitable – that includes drought, severe storms and high winds. In fact, this is not too surprising – humanity has learned how to cope with extreme weather, and human beings occupy regions from the most frigid to the most scalding, from sea level to heights where sea-level-dwellers struggle to breath. Not only are we adaptable, but we have also learned how to build structures that will shield us from the forces of nature.

Of course, such protection comes at a cost. Not everyone can afford the structures needed for their preservation.  Villages are regularly flattened by storms that would leave most modern cities undamaged. Flood control measures are designed for the one-in-a-hundred year events, and they generally work – whereas low-lying areas in poor nations are regularly inundated for want of suitable defences.

Indeed, it is a tribute to the ability of engineers to protect against all manner of natural forces.  For instance, the magnitude 9 Tōhoku earthquake of 2011 (which caused the tsunami that destroyed the reactors at Fukushima) caused little physical damage to buildings, whereas earlier that year, the “mere” magnitude 7 earthquake in Wellington, New Zealand, toppled the cathedral.

So we should not fear extreme weather events. There is no evidence that they are any stronger than they were in the past, and we have generally adequate defenses against them.  Of course, somewhere our defenses will fail, but that is usually because of a design fault by man, not an excessive force of Nature. So here, on the fourth step of our journey, we can clearly see the climate change hypothesis stumble and nearly fall.


Tuesday, March 22, 2016

The Third Step - Global Warming

We have shown how the carbon dioxide in the atmosphere is increasing, and how that increase is the direct result of burning fossil fuels. Now we need to consider the impact of more carbon dioxide in our air.

Carbon dioxide scatters infra-red over a narrow range of energies.  The infra-red photons, which should be carrying energy away from the planet, are scattered back into the lower troposphere. The retained energy should cause an increase in the temperature. 

A photon with a wavenumber between about 550 and 700 per cm which has been absorbed by a carbon dioxide molecule is almost instantaneously re-emitted in a different direction with a slight loss of energy. The carbon dioxide molecule gains a very small amount of energy in the process, insufficient to raise its temperature significantly. Any heating that could be observed has to do with the scattering of infra-red radiation back towards the surface rather than escaping into space.

At about 5km above sea level, we lose as much radiant heat to space as is required to keep the planet in thermal balance. If we look back at Earth from space, we can get a good idea of the impact of carbon dioxide:

The blue line shows the spectrum of a black body radiating at 280 degrees K, which is close to what would be seen if there were no absorbers in the atmosphere.  The red line shows the actual spectrum.  The difference between these two is the energy scattered by various infra-red-active species. Water vapour has an effect across the entire spectrum - it is the major greenhouse gas. carbon dioxide adds to the scattering between about 550 and 700per cm, and ozone (O3) plays a part between 950 and 1100 per cm. 

One of the features of the carbon dioxide absorption is that the effect drops off logarithmically with concentration. Doubling the concentration will not double any effect. Indeed, at present there is ~400ppm in the atmosphere.  We are unlikely see a much different world at 800ppm. It will be greener - plants grow better on a richer diet - and it may be slightly warmer and slightly wetter, but otherwise it would look very like our present world.

However, just as any effect will lessen proportionately with increase in concentration, so it will increase proportionately with any decrease.  If there are to be any observable effects, we should have seen them already.  Have we?

There are "official" historical global temperature  records. A recent version from the Hadley Climate Research unit is: 

The vertical axis gives what is known as the "temperature anomaly", the change from the average temperature over the period 1950-1980. Recall that carbon dioxide only became significant after 1950, so we can look at this figure with that fact in mind:
* from 1870 to 1910, temperatures dropped, there was no carbon dioxide effect
* from 1910 to 1950, temperatures rose, there was no carbon dioxide effect.
* from 1950 to 1975, temperatures dropped, carbon dioxide increased
* from 1975 to 2000, both temperature and carbon dioxide increased
* from 2000 to 2015, temperatures were flat but carbon dioxide increased strongly.

Does carbon dioxide drive temperature changes? Looking at this evidence, one would have to say that, if there is any relationship, it must be a very weak one. In one study I undertook, I found that there was a 95% chance that, over a period of a century, the temperature would change naturally by as much as +/-2degrees C. During the 20th century, it changed by about 0.8degrees C. The conclusion? If carbon dioxide in the atmosphere does indeed cause global warming, then the signal has yet to emerge from the natural noise.

One of the problems with the "official" temperature records such as the Hadley series shown above is that the official record has been the subject of “adjustments”. While some adjustment of the raw data is obviously needed, such as that for the altitude of the measuring site, the pattern of adjustments has been such as to cool the past and warm the present, making global warming seem more serious than the raw data warrants.

It may seem unreasonable to refer to the official data as “adjusted”, but its basis is what is known as the Global Historical Climatology Network, or GHCN. But adjusted it has been. For example, it is possible to compare the raw data for Cape Town, 1880-2011, to the adjustments made to the data in developing GHCN series Ver. 3:

The Goddard Institute for Space Studies is responsible for the GHCN. The Institute was approached for the metadata underlying the adjustments. They provided a single line of data, giving the station’s geographical co-ordinates and height above mean sea-level, and a short string of meaningless data including the word “COOL”. The basis for these adjustments is therefore unknown, and the fact that about 40 successive years of data were “adjusted” by exactly 1.10 degrees C strongly suggests fingers rather than algorithms were involved.

One can only conclude that there has been so much tampering with the "official" records of global warming that they have no credibility at all. That is not to say that the Earth has not warmed over the last couple of centuries.  Glaciers have retreated, snow-lines risen. There has been warming, but we do not know by how much.

Interestingly, the observed temperatures are not unique. For instance, the melting of ice on Alpine passes in Europe has revealed paths that were in regular use a thousand years and more ago. They were then covered by ice which has only melted recently. The detritus cast away beside the paths by those ancient travellers is providing a rich vein of archaeological material.

So the world was at least as warm a millennium ago as it is today. It has warmed over the past few hundred years, but the warming is primarily natural in origin, and has nothing to do with human activities.  We do not even have a firm idea as to whether there is any impact of human activities at all, and certainly cannot say whether any of the observed warming has an anthropogenic origin. The physics say we should have some effect; but we cannot yet distinguish it from the natural variation.

Those who seek to accuse us of carbon crime have therefore developed another tool - the global circulation model. This is a computer representation of the atmosphere, which calculates the conditions inside each 5km x 5km x 1km slice, and links them to each adjacent slice (if you have a big enough computer - otherwise your slices have to be bigger).

The modellers typically start their calculations some years back, for which there is a known climate, and try to see they can predict the (known) climate from when they start up to today.  There are many adjustable parameters in the models, and by twiddling enough of these digital knobs, they can "tune" the model to history. 

Once the model seems to be able to reproduce historical data well enough, it is let rip on the future. There is a hope that, while the models may not be perfect, if different people run different tunings at different times, a reasonable range of predictions will emerge, from which some idea of the future may be gained.

Unfortunately the hopes have been dashed too often. The El Nino phenomenon is well understood; it has a significant impact on the global climate; yet none of the models can cope with it. Similarly, the models cannot do hurricanes/typhoons - the 5kmx5km scale is just coarse. They cannot do local climates - a test of two areas only 5km apart, one of which receives at least 2 000mm of rain annually, and the other averages just on 250mm, failed badly.  There was good wind and temperature data and the local topography. The problem was modelled with a very fine grid, but there were not enough tuning knobs to be able to match history.

Even the basic physics used in these models fails. The basic physics predicts that, between the two Tropics, the upper atmosphere should warm faster than the surface. We regularly fly weather balloons carrying thermometers into this region. There are three separate data sets, and they agree that there is no sign of extra warming:

The average of the three sets is given by the black squares. The altitude is given in terms of pressure, 100 000Pa at ground level and 20 000Pa at about 9km above surface. There are 22 different models, and their average is shown by the black line.  At ground level, measurement shows warming by 0.1degrees C per decade, but the models predict 0.2degrees C per decade.  At 9km, measurement still shows close to 0.1degrees C, but the models show an average of 0.4degrees C and extreme values as high as 0.6degrees C. Models that are wrong by a factor of 4 or more cannot be considered scientific. They should not even be accepted for publication - they are wrong.

The hypothesis that we can predict future climate on the basis of models that are already known to fail is false. International agreements to control future temperature rises to X degrees C above pre-industrial global averages have more to do with the clothing of emperors than reality.

So the third step in our understanding of the climate boondoggle can only conclude that yes, the world is warming, but by how much and why, we really haven't a clue.