I hope the Climate Activists are proud of the effect their lies are having on the younger generation

Peter Bernard Ladkin: 
 

dcbwhaley: 
 

We really did ought to wait until we are 100% sure - OK 99.9% - that mankind is causing climate change….

Um, we are very much 100% certain. The (technical part of the) discussion here has been about the extent of anthropogenic effects, not whether there are any.

Besides, this kind of thinking is no longer generally considered appropriate in this context . Health, medicine, engineering safety, and now parts of climate science have been based for a long time on the notion of risk. 

Um. I disagree.

Roger has given you enough facts and figures to totally discredit your thinking.

dcbwhaley: 
 

We really did ought to wait until we are 100% sure - OK 99.9% - that mankind is causing climate change….

Um, we are very much 100% certain. The (technical part of the) discussion here has been about the extent of anthropogenic effects, not whether there are any.

Besides, this kind of thinking is no longer generally considered appropriate in this context . Health, medicine, engineering safety, and now parts of climate science have been based for a long time on the notion of risk. 

Let us suppose you smoke cigarettes. Then there is a one in two chance you will die from a disease strongly causally related to your smoking. It is not certain. You might be like ex-Chancellor Helmut Schmidt and chain smoke well into your mid-nineties before keeling over. It is also not certain that you will suffer a myocardial infarction. It is not certain that you will contract lung cancer. But the chances are enormously raised. 

Safety engineering has been based on the identification and assessment of risk and its mitigation for a quarter century. 

Of course, one of the encouragements for basing reasoning on risk was the argument from tobacco companies, similar to yours, that it wasn't certain that smoking caused ill health and it was inappropriate to take legal measures against use of their product until it was. People ultimately did not agree with that proposal, and neither did health-insurance companies in the places where people need health insurance, and people such as myself are now very thankful that we can go about our daily lives without having to encounter tobacco smoke. 

If you're going to point a finger…

Sunday morning read…

Maurice Strong, Climate Crook – Quadrant Online

dcbwhaley: 
 

Pass me the tinfoil hat

You'll need the extra thick stuff to stop this ‘unprecidented’ level of brainwashing going on today!

dcbwhaley: 
 

We really did ought to wait until we are 100% sure - OK 99.9% - that mankind is causing climate change before we make any changes in our behaviour at enormous economic cost

Absolutely correct, if it were true, I'd be the first in the queue to act on AGW CO2, but only if it was wholly proven to be the control knob for the current phase of global warming. (incidentally the pause in warming is now 6 years and 9 months old). So much for rising AGW CO2 linked to global warming!

The green agenda will bring serious social problems, what with our joke of an energy system in the UK, skyrocketing gas prices meaning heating or eating, government solution being to chuck more tax payers cash at the needy, while adding more green tax to our energy bills to pay for this and yet more proposed subsidised farming of wind/solar.

The only solution if we do not want to burn our reliable fossil fuels  is Small Modular Nuclear Reactors. Simple as that. Everyone is happy, well almost everyone..

We really did ought to wait until we are 100% sure - OK 99.9% - that mankind is causing climate change before we make any changes in our behaviour at enormous economic cost

Pass me the tinfoil hat

Roger Bryant: 
 

If that is the case then trying to base AGW on a limited northern hemisphere weather pattern is similarly not valid. If you look at the Met office combined graph the rapid ~1°C temperature rise between 1970 and 2000 only appears in the northern hemisphere. It does not appear in the southern hemisphere.

I'm puzzled about what you think this means.

Ocean circulation as well as wind circulation is largely hemispherically contained (although for wind it makes more sense to divide into three: north, tropics and south). 

Most of the anthropogenic contribution to climate (if you think there is some, which I do) will originate/have originated in the northern hemisphere, because that is where most of the sources are and have been. You'd expect northern-hemispheric causes to have northern-hemispheric effects, and you'd generally expect to see those effects manifest less in the southern hemisphere. 

 

This gives two scenarios:

1) The MWP and LIA are valid climate effects and need to explained by the climate models especially the anthropogenic factors.

2) The CET rise from 1950 used by Stott is merely a northern hemisphere weather effect and can be ignored. Therefore it is not caused by anthropogenic factors.

You can’t have it both ways.

I don't follow this line of reasoning at all. 

If the MWP and LIA are indeed climate phenomena then they had causes and presumably we can clarify these causes somewhat, subject to the limitation that they are historical effects. Suppose we accept Simon Barker's point that they were northern-hemispheric phenomena.

The Karoly-Stott phenomenon is also a northern-hemispheric phenomenon, obviously.  

Why does a coherent explanation of MWP/LIA preclude the Karoly-Stott explanation of their phenomenon?

And how is an attribution with high confidence of a significant anthropogenic factor in the CET rise supposed to exclude an explanation of the MWP and LIA?

The third option:

The key difference between AR5 and AR6 is the measured temperature lines. 

You are surely not seriously trying to suggest that a scale of a graph has been chosen in AR6 to mislead people? I would think most of the people bothering to try to read AR6 have known how to read 2D Cartesian graphs since their teens. 

Peter Bernard Ladkin: 
 

It is obviously helpful in discussing climate warming, for the lessons it renders. 

The Karoly-Stott analysis about how the likelihood of such a rise has increased because of anthropogenic factors is obviously generalisable to any situation in which there is enough reliable data. Indeed, it is explained in the Stone-Allen 2005 paper (available in preprint from the Oxford site). Similarlywith  the observations of Stott, Stone and Allen about the 2003 European heatwave.

The point of citing that work is this. If you can show the risk of specific adverse events of a given magnitude has increased because of anthropogenic factors, then that provides an obvious argument for taking measures to mitigate the effect of those factors.

I argue we should be doing that. 

What is your position on that? That those anthropogenic factors aren't really there? 

Thats's the point Peter, the anthropogenic factors are so small and they do not control the climate. So why scare the children and bankrupt the west?

Peter,

According to previously accepted climate science up to and including the first IPCC  AR there was a Medieval Warm Period and a Little Ice Age. These did not fit well with the CO2/AGW theories and were downgraded to limited northern hemisphere weather phenomena. Simon Baker repeats this premise earlier in this thread.

If that is the case then trying to base AGW on a limited northern hemisphere weather pattern is similarly not valid. If you look at the Met office combined graph the rapid ~1°C temperature rise between 1970 and 2000 only appears in the northern hemisphere. It does not appear in the southern hemisphere.

This gives two scenarios:

1) The MWP and LIA are valid climate effects and need to explained by the climate models especially the anthropogenic factors.

2) The CET rise from 1950 used by Stott is merely a northern hemisphere weather effect and can be ignored. Therefore it is not caused by anthropogenic factors.

You can’t have it both ways.

The third option:

3) AGW effects do exist but are much weaker than the natural climate effects so the current models grossly overestimate them.

The key difference between AR5 and AR6 is the measured temperature lines. In AR5 they have levelled off and are about to break out of the lower edge of the predictions, the black line in the black circles. In AR6 there is a steep increase in the measured temperature from around 2010 which is not adequately explained but takes them back to Dr Michael Mann’s hockey stick. You can’t attempt to scare the population, especially the younger generation, if the temperature rise is flattening off. A steep rise is what you need. In the same way the Mauna Loa CO2 values are always shown on a graph with a truncated Y axis to accentuate the rise. It’s quite easy to download the data and produce an unbiased graph.