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

[PBL] Look at point 4). Apparently this gentleman doesn't read the newspapers. He wouldn't be ablt to say that in a lecture anywhere in California. Or, I imagine, many places in Louisiana. Or in the Eifel. And it passes in this supposed review also without comment. So there are at least two people not reading newspapers :-)

[AU] With all due respect, I cannot accept grethaesque exclamations based on newspaper articles a hard evidence. 

I mentioned inter alia the unprecendented California wildfire season and the heatdome that built itself up in July. I also mentioned that I lived there for nearly twenty years and have colleagues who still do, with whom I am in touch. Calling that “grethaesque exclamations based on newspaper articles” does suggest the type of discussion you seem comfortable with.

For the record, I don't think such comments have a place in any rational discussion about whether global warming is real, what the evidence is, and what to do about it. 

???

Peter Bernard Ladkin: 
 

I mentioned inter alia the unprecendented California wildfire season and the heatdome that built itself up in July. 

 

A number of people have been arrested for starting these so called wildfires. Some of these people are said to be scientists. 

The rescent heat dome is one of those incidents where ‘all the planets aline’, perfect storm scenario.

I think:

1. they are scared
2. they don't trust the authorities and corporations
3. as infuriating as we may find it, they are not “just” being difficult; they are genuine and committed (I think the same thing is true of anti-vaxers).

If we don't like their opinion, we can engage with them on an open transparent level which seeks true understanding, but if they (and we) come away with the same opinions, everyone has to respect that and let it go.

Personally, I don't blame them given the destruction humans have wreaked on the planet and that multi-nationals and co-opted governments lie, cheat, steal and blat other folk left right and centre as suites them.  Profit at any cost.  It is unsustainable and abusive.

Although interesting, being the longest measured temperature series, the CET is not very helpful in discussing global warming as it is just 3 points in England which may or may not reflect global conditions. What is the global average temperature?

There are a number of series run by various organisations. The UK Met office used to run a comparison but stopped updating this is 2010 (why?)

There are significant differences between the two hemispheres, the northern hemisphere being similar to the CET with a drop 1950 - 1970, a rise of around 1°C to 2000 and then a flattening off.

IPCC AR5 split there global temperature between land and ocean. This tends to smooth out the drop in the northern hemisphere between 1950 and 1970. Again we have a rise of around 1°C  and they note the flattening off after 1998.

IPCC AR6 presents a much more extreme view. The previous reduction in the rate of rise has disappeared with no obvious explanation other than maybe ‘new datasets and methods’ (fudge the numbers to get what you want). The earlier warm periods and the little ice age are also not there.

I accept that as we learn more and develop new techniques that older data needs to be revisited. I am suspicious when every change moves the data nearer to your prediction and the political goals. Finally a couple of thoughts on FLOP26:

Peter Bernard Ladkin:
I mentioned inter alia the unprecendented California wildfire season and the heatdome that built itself up in July.

Even if that unfortunate California wildfire season was unprecedented, the trend does not seem to be global. Old newspaper articles have suggested that wildfires in US, Australia and Siberia have been of lower magnitudes recently than a century ago, satellite observations shed light on the latest decade:  

"There was a lower-than-average number of wildfires in 2020 despite hotspots such as California and Australia being hit by blazes of unprecedented intensity, the European Union's satellite monitoring service said Monday. A year of data collected by the Copernicus Atmosphere Monitoring Service (CAMS) showed that carbon emissions from fires were set to be lower than previous years and that 2020 was one of the lowest years for active fires globally.
globally fires had declined consistently since 2003 when the monitoring service began."
phys.org/.../2020-12-below-average-monster-blazes-eu.html

For the record, I don't think such comments have a place in any rational discussion about whether global warming is real, what the evidence is, and what to do about it.

I do agree with you here - although I meant no insult, I did get jollyer than usually for which I apologize (forgot a smiley). The reason for this was being fed up about the fact that with every hint of climate warming, the media screams "look out of the window at CAGW" while any cold events are explained to be just weather. Since the 60 to 65 year trends observable in climate changes exceed typical personal memory capacity, people lack own dramatic experiences and tend to believe that many weather events are extraordinary.
 
Regarding the "hockey stick season" re-opened by IPCC AR6 SPM graph a) above: one might find analysis of underlying PAGES2K reconstruction by Dr. Stephen McIntyre interesting:

climateaudit.org/.../

Some of the trump cards of the "warmists" have always been the poor melting polar ice caps. At least in case of the Antarctic glaciers, it is proven beyond doubt by now that underwater volcanoes are to blame, not the atmospheric CO2. If of interest, have a look at most recent research about the Pine Island Ice Shelf (2018) and Thwaites Glacier (2021), melting of which has allegedly previously been attributed to human activities by hundreds of reserch reports. Similar issues can be seen in the Arctic - the ice is melting due to warmer waters, not atmospheric heat. The Iceland and Greenland mantle plumes have been recently studied, but the sea ice is not doing as bad as some have forecasted.  

I would suggest an analogy of ground beef handling to describe the situation with widespread CAGW propaganda these days: one does not have to think about poor animals being herded and slaughtered while making meatballs in the comfort of own kitchen; similarly, most of the media figures do not consider how the climate science is made and how much of it is still valid, operating in good faith. What was started based on hypothetical risk assessment as a precautionary principle may be already invalidated by empirical data. I tend to believe in measurement, not modelling, and expect integrity of scientists. 

Roger Bryant: 
 

Although interesting, being the longest measured temperature series, the CET is not very helpful in discussing global warming as it is just 3 points in England which may or may not reflect global conditions. 

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? 

 

What is the global average temperature? …..

 

IPCC AR5 split there global temperature between land and ocean…… IPCC AR6 presents a much more extreme view. The previous reduction in the rate of rise has disappeared 

I don't see much difference between the data you quote from AR5 and AR6, except for the mode of presentation. Can you tell us why you find AR6 “much more extreme”?

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.

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?

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.