What is the utility of the globe to humanity at this particular point in the evolution of the Earths disparate climatic regimes? Has there been an improvement or deterioration in recent times. To answer these questions we must look at the pattern of temperature change by latitude.
The warmer latitudes of the northern hemisphere
Figure 1 The Northern Hemisphere between the equator and latitude 60° north.
Figure 1, relates to that part of the globe between the equator and 60° north where the density of human settlement is greatest. The data indicates that:
- Both summer maxima and winter minima fell away between 1948 and 1976.
- Summer maxima and winter minima then rose until 1998.
- Summer maxima and winter minima have been fairly stable since the turn of the century.
- In 2008 and 2011 winter minima are almost as cool as those experienced during the period of cooling between 1948 and 1976.
- The January minimum exhibits much more variability than the July maximum.
- Summer maxima are short of the 25°C optimum temperature for plant growth.
- Cooling is evident after the eruption of Pinatubo in 1991.
The habitable part of the northern hemisphere is three degrees warmer in July than the southern hemisphere in January. This is due to atmospheric heating and cloud loss associated with the higher ratio of land to sea in the northern hemisphere. The sea is transparent and absorbs solar radiation. The surface of the land heats quickly and returns energy to the atmosphere, warming it and reducing cloud cover. Hence we have the paradox that the Earth as a whole is warmest when it is furthest from the sun. There can be no better illustration of the importance of cloud cover in determining surface temperature. The Earth tells us about feedback effects when the atmosphere is loaded with energy. The feedback is positive, due to the loss of cloud.
Hypothetically if the atmosphere became drier over time, cloud cover would diminish and temperature would increase. Conversely, if the atmosphere became wetter temperature would decrease. The drying of the atmosphere (reduced precipitable moisture) has been a powerful source of natural climate variation and directly contradicts the postulated wetting of the atmosphere that is built into the climate models beloved by the United Nations International Panel on Climate Change. Those who write UNIPCC reports do not let the facts stand in the way of a good story. Check out how the atmosphere dried between 1948 and 2005 at: http://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl So, the Earth system itself tells us that the water vapour feedback effect as the atmosphere warms, is negative. The atmosphere becomes more transparent to outgoing long wave radiation, not less transparent.
The warmer latitudes of the southern hemisphere
Figure 2 The Southern hemisphere between the equator and latitude 50° south
In relation to the zone between the equator and latitude 50° south:
- Both maximum and the minimum air temperatures increased between 1948 and 1977 and jumped to a new plateau in 1978. These latitudes of the southern hemisphere warmed at precisely the same time that the same latitudes in the northern hemisphere cooled.
- A plateau was maintained between 1978 and 2011 as temperature in the northern hemisphere increased strongly.
- There is a marked ‘Pinatubo’ effect after 1991, more so that in the northern hemisphere.
- Summer maximums (January) are more variable than winter minimums.
- Winter minima are raised and stabilized to an extent by the radiation of heat from the northern hemisphere that drives the cloud away in mid year. The atmosphere dried after 1978 and the consequent loss of cloud should have produced a warming surface. The fact that the surface temperature is stable after 1978 suggests that some other influence has been responsible for a compensatory cooling.
The years 1973, 1983, 1978 and 2010 are outliers in that summers are much warmer, peaking at 20.25°C. Let us note that even in the warmest summers, maximum temperatures are well short of that in the northern hemisphere and well short of the optimum for plant growth. It is nonsense to suggest that the globe is becoming too warm if the global mean reflects warming in parts that are insufficiently warm. This part of the world is insufficiently warm.
This part of the southern hemisphere exhibits much more inter-annual variability than is seen in the northern hemisphere and the variability is greatest when the southern oceans face the sun in December to March. Questions arise:
- Why did the southern hemisphere warm between 1948 and 1978 as the northern hemisphere cooled? Is this consistent with the suggestion that it is change in the atmosphere that is responsible for the temperature increase?
- Why is there greater variability in both summer maxima and winter minima in the southern hemisphere than the northern hemisphere, particularly as this hemisphere is dominated by water which is supposed to have a moderating influence on climate? Is this not an indicator of a phenomenon that drives climate change by hemisphere rather than impacting the globe as a whole?
- Why did the summer maximum in the southern hemisphere stabilize after 1978 as northern hemisphere temperature increased?
- Should we really be concerned at this rise in temperature in the southern hemisphere when the current temperature regime is sub optimal for plant growth?
- How valid is the global mean as a metric of planetary welfare if it is inflated by a rise in temperature of a location that is insufficiently warm?
- Should we not congratulate ourselves on our good fortune that the southern hemisphere is slightly warmer today than it has been in the recent past rather than beat our breast in anguish?
Since the late 1970’s the habitable latitudes of the southern hemisphere have made little contribution to the advance in global temperature. The question arises: if greenhouse gases of anthropogenic origin are responsible for the increase in the global mean that is evident after 1978, why is it that we see little or no advance in either maxima or minima in the vast bulk of the southern hemisphere? Can we eliminate the greenhouse theory as irrelevant on the basis of this information?
Why is it considered that the globe is in danger of becoming too warm? Our interest is in ensuring that the capacity of the planet to support life in all its forms is not impaired. In the warmest parts of the globe, the parts considered thus far, temperature is sub optimal for plant growth and particularly so in the southern hemisphere. All life depends upon plants. We would be better off if the planet were warmer. It is further cooling that represents a threat to human welfare. We have plenty of scope on the upside.
Let’s put these highly pertinent questions aside for the moment and look at the climate of the rest of the globe.
In high latitudes the thermal regime is either seasonally or perennially cold. I am sure that most will agree that climate pole-wards of 60° in both hemispheres is inhospitable to man. These regions contribute to the global average temperature. But it is already apparent that the ‘global average’ is a statistic more suitable for posturing and propaganda than practical decision-making. I don’t think we will ever persuade the people of Scandinavia, Siberia or Alaska that winter cold is a good thing.
One has to congratulate the proponents of the AGW cause on their tactics, if not their science. Concentrating on the global mean is a good debating technique. They have won over the parroting media and the coffee shop ‘intelligentsia’. They have the universities stacked with ecologists and environmentalists. They have well funded bureaucracies acting as environmental policemen. Local governments are obsessed with rising sea levels, sustainability and preserving the bush. But, can the environmental movement live with its conscience when the grand theme of anthropogenic climate change is so patently flawed? Is there a conscience?
Figure 3 The northern hemisphere north of latitude 60° north.
North of 60° north, a region conveniently described as the ‘Arctic’, we see relatively large swings in temperature over time, concealed in this graph by the expanded scale due to the large annual range. However, the summer maximum is remarkably invariable. Winter minima are highly variable and have been rising over the entire period of record. Plainly climate change effects the minimum temperature with little change in the summer maximum. But anthropogenic influences are not capable of distinguishing between summer and winter. It must be some other factor that is causing change.
Despite the increase in winter temperatures there is little prospect that this area will be favorable for human settlement at any time in the near future. Temperatures between 10°C and minus 20°C are seriously cold. Those few who live in this part of the world will no doubt be pleased about the reduced incidence of extreme cold in winter and the very slightly longer period of temperatures favorable to plant growth that are available on the southern margins of the zone, the reduced incidence of ice on their roads and snow on the roof.
In terms of productivity, and sustainability, the variation in temperature north of latitude 60° north should be of little interest to us, particularly when the mean is simply responding to change in the winter minimum when nights are long, bears must hibernate and self respecting Eskimos are holed up in their igloos. But, perhaps this is just an ill informed Australian perspective. Perhaps the Finns actually enjoy their long winter nights, warm saunas, running naked in the snow while birching each other under the stimulating influence of vodka? This could be fun, but perhaps for a shorter interval, not the entire winter.
Figure 4 The Southern Hemisphere south of latitude 60° south.
South of latitude 60°south, summer maxima are well into the freezing range and have declined over the entire period ensuring that ice is never in danger of melting. But there has been a strong increase in winter minima since 1970 that is presumably much appreciated by male penguins that stand together resolutely keeping their eggs warm. The wind chill factor is aggressive. Three million square miles of ocean freezes on the margins of Antarctica in winter and despite the increase in the winter minimum the area of ice is increasing.
The mean temperature in Antarctica has increased despite the strong fall in summer maxima. With summer maxima currently at minus 5°C and winter minima at minus 25°C this part of the world is for hardy explorers with too many fingers and toes. It is a place for research rather than habitation.
The strong increase in the ‘mean’ temperature in the Antarctic contributes to the rise in the global average. Again, we must ask just how appropriate this ‘global average’ really is. If we are truly concerned with planetary welfare, the gross product available for consumption by human and other species, the area of the globe capable of supporting habitation, personal comfort and the supply of vodka, what happens in this part of the world should be of little concern, unless the ice were to melt and there is no chance of that happening. Despite the increase in the winter minimum temperature the Antarctic ice pack is still as large as Antarctica itself, and growing.
Drawing the threads together
Firstly, let’s acknowledge that the idea that the earth is in danger of overheating is nonsense. Our planet would be more habitable if it were several degrees warmer.
Secondly we must ask whether the pattern of temperature change that we observe can be explained by the greenhouse thesis. The answer must be in the negative. If we seek to explain change in temperature we must look for a mechanism that affects temperature between November and March to account for the variability that is evident at that time. In addition we must explain the strong variation in winter minimum temperature at high latitudes.
We don’t have to look far for the cause of the variation in temperature between November and March. It’s the El Nino Southern Oscillation. Is there any agreement as to the cause of this phenomenon? No. Can we rule it out as a possible cause of climate change? Obviously not.
No ‘forcing’ like trace gas composition, that is common to the globe as a whole, and subject to the same increase regardless of season can explain the observed pattern of temperature change. Plainly, something entirely different, something that is hemispheric and seasonal rather than global in its impact, is responsible for this change. I think we will wait in vain if we expect the UNIPCC climate panel to discover the cause of the variations that we observe. These people take their cue from Lord Nelson. Look the other way. Turn a blind eye to that you do not wish to see.
But, carbon taxes and emissions trading schemes should be off the agenda. And we should forget about our ‘carbon footprint’ and the notion of ‘carbon pollution’. That is nonsense. It is about as useful as the medieval notion that climatic misfortune is due to witchcraft and bad behavior. Personally, I earnestly hope that the writing of this piece does not result in the burning of the author at the stake.