A summary of global warming

I have just been asked for a full summary of global warming for new arrivals who need to know everything from A-Z and realised I didn't have one. Diagrams and links to follow

Most of the main criteria are taken from the UN IPCC reports.

The main proposition: Added CO2, from the long term average of 260ppm (parts per million) upwards, could cause an amount of associated temperature rise which may cause more problems than benefits.

The exact amounts are the existing greenhouse effect of the atmosphere (official UN figures) which say from the added 33C from the effect, the majority comes from water vapour, and 1C comes from 260ppm of CO2. If you double CO2 is should add 1C, ie 520ppm would cause 1C extra and 1040 would add 2C. The UN claim the problems (mainly from rising sea level from melting land ice, and heatwaves) would start to outweigh the known benefits (increased food production, fewer wars, fewer deaths from cold and less energy usage) at around 2C.

Of course, CO2 would need to reach 1000ppm for this to happen, which is probably impossible, as with all the fossil fuel we are currently producing we have added 140ppm since 1850. Also CO2 does not last that long in the atmosphere, dropping out after a century or less. So when the media go crazy about possible warming, they fail to point out that the temperature has risen less than 1C since 1850. The temperature never remains the same, as it rises and falls between ice ages and smaller cycles, so as we have been coming out of once since the 18th century the temperature was already rising. Doing the simple equation, the rough existing amount is around a quarter to half the actual rise of 0.8C, therefore the amount from CO2 was 0.4-0.6C. Double that and you get a mean of 1C, exactly as predicted. Not anywhere close enough to cause problems.

So in that case why did the UN think it would be such a problem? Two words, positive feedback. This is mainly from the warming evaporating more of the ocean adding more water vapour to the atmosphere which is a serious greenhouse gas. The satellites measuring it confirm that it has not increased, and corroborates the lack of positive feedback. As no delay was expected it is reasonable to say there was no positive feedback and the water vapour could just as easily increase cloud cover, which blocks the sun and reduces the temperature, which has happened to a slight degree.

The UN state you cannot attribute individual weather events to warming, and there is no agreement overall that warmer weather causes more of them, only possibly more intense events. Also until 2001 the past records showed a number of warmer average world temperatures in history, which Michael Mann single handedly wiped out with his hockey stick diagram. The UN then revised it again where the two graphs were merged and averaged out. People can still use all three as it is not possible to prove which is correct, although the fact crops were grown all over the sub-Arctic regions which require a far higher temperature proves the northern hemisphere at least was warmer. The fact they can't prove whether the entire planet was warmer shows how rough proxy methods are, even the current temperatures have recently been revised in America.

The sea level is the most direct response to temperature. In the 20th century it rose 8 inches. After an ice age it can rise hundreds of feet. The current trend for the 21st century is a few more inches than the 20th. That directly relates to a stable and minimal temperature change and is far easier to measure than the world average temperature. That was measured by proxies (indirect indicators like ice cores and tree rings) before 1850 for the world, and thermometers until 1979 when they were supplemented by satellites. These vary in every time and location and the large areas with none need to be estimated. Currently there are four main temperature collections, which are not all in agreement. They measure land, sea and atmospheric temperatures and the difference between them and a previous point (anomaly). The oldest temperature record taken directly is the 17th century Central England record which shows very little warming and is the most reliable local record. In fact it is very hard to record average temperature, which is why they prefer to use anomalies, but the inherent measurement problems never go away. Other events such as weather and jet streams etc are also caused by far too many conditions to attribute to warming or any other single area. However the one linear correlation between temperature is with sea level. There is a known (generally, not exactly as the depth is questionable) amount of land ice on the planet. This requires a specific level of warming to melt, and that in turn flows into the sea causing a specific amount of sea level rise, which again is far easier to measure than temperature, although not exact. Therefore you can draw a linear graph between temperature rise, ice melt and sea level rise. As the rate of sea level rise has barely changed since the 19th century then maybe everything else they claim is irrelevant.

To summarise, there is a finite amount of fossil fuel on the planet. As we burn it it collects in the atmosphere, causes a small amount of warming and is replaced by more currently at a faster rate than it drops out. But overall we have seen CO2 rise by 50% and the associated temperature rise is both below the crucial 2C trend and shows a total absence of feedback. The incredible range of UN temperature projections for 2100, which we will not live to see, go between 1.5 and 6C. The chance of them missing with such a huge goalmouth is low, but totally irrelevant, as even if it falls none of us can ever know. It is not scientific to produce an experiment which cannot be completed, or the range is larger than the error margin, so it fails on all counts, and the 2015 temperature has fallen below the range they made altogether. CO2 continues to increase and the temperature has barely risen for 18 years. The media and politicians don't like you knowing that or their entire claims will fall apart.