Yet more proof.

[Nick]

And CO2 is a greenhouse gas along with a bunch of others. Plus you mentioned oceanic CO2 release at the end of an ice age.

Regardless of which gas you pick almost all have same property of being more opaque to the IR spectrum than visible.  You can literally see this. Name an atmospheric gas that isn't mostly transparent.

Interestingly, solid particulates like ash and smoke behave in almost the complete opposite fashion being more transparent to IR than visible.

So any large scale particulate dispersal could cause global cooling both directly and via changing the properties of clouds.

There appears to be solid evidence that human activity, particulates from combustion and industry, has had a cooling effect in the latter part of the last century. Ironically effort to reduce pollution habe reduced that effect.  But it is an example of human activity affecting the climate albeit over a shorter timescale.

So you dispute the 23% solar radiation that the atmosphere blocks? Ozone. 

[BeElBeeBub]

I never suggested selecting anything.  But if you insist on finding 'averages', then you should include all available data.  A better way to gauge change would be to show a graph of averages, for all available data.  For example, the average for each month, over all years.  Or the average for April, for every year.

Please do so.  You can dig into the met office database and extract the data, then graph it on excel or similar. I'm currently working on my phone so I'm not going to massacre my thumbs trying to use "mobile" excel.

As for the mean average, what possible value is there in finding the mean of minimum and maximum? Normally mean averages are found by adding all data points and dividing. Your suggestion seems meaningless.

That is how the "daily mean air temperature" is calculated in the UK. For a long time the only reading available for a given day were the max and min due to the technology available so the only means available was max+min/2  Even though hourly and by the minute readings are now available the old method is still used for consistency and consistency is important if you are looking at long term trends.

It doesn't affect the impact of the results we are discussing as those were driven by warmer night temperatures and the fact we are only looking at the minimum would actually tend to make the nights look cooler than they actually are. Ie a night where it was mostly 8C but dipped briefly 7C  for a few minutes would be recorded as 7C.

You could look at the Max or the Min, and there is still an anomaly.

[BeElBeeBub]

Can you point to the point where I mentioned CO2 above? I said greenhouse gases, and they remove about a quarter of solar radiation: that's from NASA.

And CO2 is a greenhouse gas along with a bunch of others. Plus you mentioned oceanic CO2 release at the end of an ice age.

Regardless of which gas you pick almost all have same property of being more opaque to the IR spectrum than visible.  You can literally see this. Name an atmospheric gas that isn't mostly transparent.

Interestingly, solid particulates like ash and smoke behave in almost the complete opposite fashion being more transparent to IR than visible.

So any large scale particulate dispersal could cause global cooling both directly and via changing the properties of clouds.

There appears to be solid evidence that human activity, particulates from combustion and industry, has had a cooling effect in the latter part of the last century. Ironically effort to reduce pollution habe reduced that effect.  But it is an example of human activity affecting the climate albeit over a shorter timescale.

[Scott777]

Sorry, what past years would you like to select in order to not be selective?

The past 30 years seems to be the standard way of describing average climate (temperature, rainfall etc).  If you wanted to use 1970-2000 as your baseline you could but it would simply show the temperature anomalies as even bugger

The max and mins are the easily accessible data. The average is simply the mean of the 2. It's calculated this way because it means we can compare with records going back to the mid 1800's when the technology meant they could only measure daily max and min.

I never suggested selecting anything.  But if you insist on finding 'averages', then you should include all available data.  A better way to gauge change would be to show a graph of averages, for all available data.  For example, the average for each month, over all years.  Or the average for April, for every year.

As for the mean average, what possible value is there in finding the mean of minimum and maximum?  Normally mean averages are found  by adding all data points and dividing.  Your suggestion seems meaningless.

[Nick]

For what it's worth last year was likely the hottest year in at least the last 100k (as shown by your graph).

Oh look, this pattern of heat repeats every 100K years: the point we are at in time now, but you clearly don't see the significance of this pattern, it has to be us 

[Nick]

This is wrong. This is not how CO2 acts in the atmosphere.

The key point you seem to miss is that incoming energy (sunlight) and outgoing energy (earth longwave emissions) are at different frequencies



The atmosphere is nearly transparent to most of the incoming radiation (the exception being clouds) whilst being more opaque to the wavelengths that are outgoing.

You keep making basic mistakes in the science behind this but then insisting you are right whilst people who understand this stuff really well are wrong.

Can you point to the point where I mentioned CO2 above? I said greenhouse gases, and they remove about a quarter of solar radiation: that's from NASA. 

[BeElBeeBub]

This is why you are selective which data you use.


Oh look we have a problem.



Oh, no we don't.



Have you ever done any work with PID control and hysteresis? If you have you will know having an integral time of 750 years causes a massive headache, also anything we are seeing now will have happened centuries ago.

We have monthly data going back 140 years.
There is literally no reliable data on a monthly resolution further than this.

If you want to use global temperature for a year, then fine, obviously we can't use that to discuss 2024 so far as we haven't finished the year.

For what it's worth last year was likely the hottest year in at least the last 100k (as shown by your graph).



 

[BeElBeeBub]

Finally you get it.
And the greenhouse gases that are produced from an ice age standstill block the solar radiation coming in, every molecule radiated 50% back into space so more
you have, more 50%'s are blocked, that is how the cycle is completed. Which is why I said the Earth has its own control mechanism. We are pretty much as far from
an ice age as we have ever been, of course we are at a warm part of the cycle, but it isn't down to human activity, it's natural. If you want to discuss humans polluting the planet and plastic in the sea I have a totally different stance.

This is wrong. This is not how CO2 acts in the atmosphere.

The key point you seem to miss is that incoming energy (sunlight) and outgoing energy (earth longwave emissions) are at different frequencies 



The atmosphere is nearly transparent to most of the incoming radiation (the exception being clouds) whilst being more opaque to the wavelengths that are outgoing.

You keep making basic mistakes in the science behind this but then insisting you are right whilst people who understand this stuff really well are wrong.

[Nick]

Using this type of data selection according to you Dinosaurs never existed. 

[Nick]

No, the period used (1991-2020) is the warmest baseline they could have picked.

If you want to use the 1970-2000 baseline the April mean anomaly would be greater.

April was the 16th warmest out of 141, May was the warmest of 141.

It doesn't matter how you try and electively pick the data, April and May were warm months.

This is why you are selective which data you use.


Oh look we have a problem.



Oh, no we don't.



Have you ever done any work with PID control and hysteresis? If you have you will know having an integral time of 750 years causes a massive headache, also anything we are seeing now will have happened centuries ago. 

[BeElBeeBub]

It's all selective, they've chosen the coldest period measure the 0.8 degree temperature increase. They're selective because if they use the full spread of data there is no anomaly and they don't get big fat grants.

No, the period used (1991-2020) is the warmest baseline they could have picked.

If you want to use the 1970-2000 baseline the April mean anomaly would be greater.

April was the 16th warmest out of 141, May was the warmest of 141.

It doesn't matter how you try and electively pick the data, April and May were warm months.

[BeElBeeBub]

Why 30 years?  Why not 1970 to 2000?  Why not 2021, 2022, 2023?  Why mention minimum and maximum?  That does not say anything about average.  This is all selective. 

Sorry, what past years would you like to select in order to not be selective?

The past 30 years seems to be the standard way of describing average climate (temperature, rainfall etc).  If you wanted to use 1970-2000 as your baseline you could but it would simply show the temperature anomalies as even bugger 

The max and mins are the easily accessible data. The average is simply the mean of the 2. It's calculated this way because it means we can compare with records going back to the mid 1800's when the technology meant they could only measure daily max and min.

[Nick]

The models are built from 1st principles. We have solid theoretical and experimental evidence that CO2 concentrations in the atmosphere affect the amount of energy radiated into space. The models don't presuppose anything, the warming effect falls out of the interactions when models.

Maybe we are at cross purposes.

You say co2 has never *driven* temperature changes before (eg ends of ice ages). Do you mean driven or initiated?

You yourself said warming can release Co2.

So we have an ice age. A cold frozen earth, glaciers over London etc. all is calm, all is bright and so on.

Then a small upward nudge (say increased solar radiation) can nudge the temperature up, which releases co2 from oceans raising the atmospheric concentration. This increases the greenhouse effect and more warming happens which release more co2, the planet warms more and then ice age ends.

This has happened before. The extra energy from the millennia long solar/orbital cycles is not enough to account for the warming we see in the records.  But a feedback mechanism using co2 greenhouse warming as you described does account for the extra warming

So the co2 didn't initiate the warming (that was the solar cycle) but it did drive the warming.

Now this time round, we are providing that initial push to increase the co2 concentrations.  The same mechanism (greenhouse effect) is happening but this time we are the initiator rather than oceans warming due to increased solar radiation.

Finally you get it. 
And the greenhouse gases that are produced from an ice age standstill block the solar radiation coming in, every molecule radiated 50% back into space so more
you have, more 50%'s are blocked, that is how the cycle is completed. Which is why I said the Earth has its own control mechanism. We are pretty much as far from
an ice age as we have ever been, of course we are at a warm part of the cycle, but it isn't down to human activity, it's natural. If you want to discuss humans polluting the planet and plastic in the sea I have a totally different stance. 

[Nick]

Why 30 years?  Why not 1970 to 2000?  Why not 2021, 2022, 2023?  Why mention minimum and maximum?  That does not say anything about average.  This is all selective. 

It's all selective, they've chosen the coldest period measure the 0.8 degree temperature increase. They're selective because if they use the full spread of data there is no anomaly and they don't get big fat grants. 

[Scott777]

The met uses 30 year blocks as the average.  That's just how it is. If you want to use a different block as your baseline you can but that just makes the April look even warmer by comparison.

For example the April averages for Kew Gardens (picked as random London location)

(period, maxC, minC)
91-20, 15.13C, 5.10C
81-10, 14.42C, 4.72C
71-00, 13.59C, 4.43C
61-90, 13.33C, 4.30C

https://www.metoffice.gov.uk/research/climate/maps-and-data/uk-climate-averages/gcpuckhb6

April (and May) were unusually warm, even if they felt crap.

Why 30 years?  Why not 1970 to 2000?  Why not 2021, 2022, 2023?  Why mention minimum and maximum?  That does not say anything about average.  This is all selective.