The climate change issue is so complex that despite what anyone says, it cannot be resolved at this time.
The earth is subject to a 100,000 year glacial cycle and we know the precise dates of the last seven. Every 100,000 years it gets very cold, then very hot. There is nothing people can do about this because planetary engineering is not within our capabilities at this time. There is a valid argument that man's activities are increasing the current rise in temperature, but since the previous graphs show very large upward and downward variations within the overall temperature rise when heading upward to the interglacial peak, which can comprise several degrees rise or fall and last for 500 or 5,000 years, there is no way to state conclusively that man's activities are entirely responsible for any trend over and above the gradual rise in temperature that will inevitably occur.
It may help to try and reduce the human factor, but when you consider what that challenge entails, it is absolutely inconceivable that efforts in the 1st world will negate the huge rises in CO2 production and so on in the developing world. China, India and South America cannot reduce their massive growth in emissions and all it does is handicap our own economies (and provide a good living for the 'warmists', who would otherwise be unemployed).
These are the raw facts, make of them what you will:
- The glacial cycle is almost as regular as clockwork, the average period is 100,000 years - but it can vary between 80,000 and 120,000 years. It never fails, and as far as we can tell, it never will.
- The last glacial temperature trough or lowest point was just 20,000 years ago. These cold stages are commonly called 'ice ages'.
- The glaciers only retreated from London 10,000 years ago.
- Perhaps you can see by now that it will get steadily hotter for about another 30,000 years, up until the inter-glacial temperature peak (when the world is considerably hotter than now). We're just 2/5ths up the graph, with another 3/5ths of temperature and sea level rise to go.
- The sea level rises and falls 195 metres each time. So far, it has risen 125 metres this cycle, so is due to rise another 75 metres (and this is just as inevitable as the sun coming up every day - you have as much chance stopping one as the other). The sea level rise is caused by the loss of or gain of ice at the poles. In order to create such dramatic height variations, virtually all of the ice must disappear and then reform in each cycle.
- Each cycle, the glaciers extend south from the North Pole as far as a point between Oxford and the Thames (London), which are only a few tens of miles apart. This appears to indicate that the temperature reaches a very similar low point each time. We might make the same assumption about the high point although there is less hard evidence for this.
- In Britain, the glaciers are at their thickest in Scotland, where they are 3 kilometers thick. The weight of the ice is so vast that it actually sinks the country in the north, and raises the south-east in a see-saw effect.
- The global rise in ocean levels has been 2mm per year for the last 200 years and has been absolutely stable even through the industrial period. This is according to the world's leading expert on sea level change, the Head of Climatology at MIT.
- However, recent satellite data seems to show that the current increase is 3mm, but has yet to be confirmed by MIT.
- The sea level rise is different in different areas. For example in south-east England the sea level rise is 5mm annually, due to the annual 2mm rise plus another 3mm due to this area sinking, caused by the post glacial spring-back in Scotland.
- From local archaeology we know that the sea level was 16 feet lower in south-east England in Roman times, 2,000 years ago. This gives a reasonable guide to local sea level rise that can be expected - plus a little more for man's activity, or for the completely erratic nature of the temperature rise and fall during the upward trend, as you prefer.
- No short-term forecasts for local temperatures can be made since although the overall trend is very strongly upward toward the inter-glacial peak, there are huge variations in the short-term rise or fall of temperature. As an example, we know that 5,000 years ago the climate in the western Scottish islands was far warmer than today. It was probably warmer than in south-east England today, and may have had a climate approaching a Mediterranean one. Agriculture was widespread and profitable for the peoples living there. Today these island are cold, inhospitable, and agriculture is virtually impossible. The temperature has fallen significantly.
- From these (undisputed) facts we see that the sea will rise inexorably; there is little or no ice at the poles at the temperature peak and it has always been that way; the temperature can rise or fall dramatically for thousands of years at a time, even though the overall trend for the next 30,000 years is going to be very strongly upward; that in 30,000 years the sea will have risen another 75 metres (but cannot rise more since there will be no ice left to melt).
From the rapid sea level rise in the last 20,000 years it does look as if most of the change in level occurs close to the glacial freeze, the trough, and the re-melt. Therefore it may well be the case that the sea level will rise quite substantially (and the polar icecaps melt, in order to provide the water), in the next 10,000 years as opposed to at the end of the cycle. In practical terms you can perhaps expect a rise of several metres within current lifespans, especially in some areas.
The right thing to do would be to try to reduce the human effect on this, if possible (which seems rather unlikely), and plan for future planetary engineering work such as perhaps an attempt to reduce the planet's albedo or even shield it from the sun. Otherwise, much of it will be uninhabitable at each end of the cycle - at the peak because it will be far too hot for agriculture, and near the trough - in 80,000 years
- because much of the northern and southern hemispheres will be under glaciers.
Our history is basically just 10,000 years old or less in the developed countries, because before that the land we occupy was beneath glaciers; and before that it was a desert - rinse and repeat. People seem to forget these things and think they are in control of the planet - what supreme arrogance.
