On Tuesday, 15 September 2020 at 10:04:51 UTC+1, Spike wrote:
On 14/09/2020 16:21, Alastair B. McDonald wrote:
On Monday, 14 September 2020 at 11:28:45 UTC+1, Spike wrote:
On 14/09/2020 08:28, Graham Easterling wrote:

it's been allowed to continue. It was always going to be difficult to get Countries to reduce carbon emissions. The economic crash of 2008 made an attempt but of course, governments were having none of that. Important steps were taken to boost car production & get CO2 emissions back on track.

In a recent BBC R4 news programme, it was claimed that CO2 levels are
higher now than than at any time in the last 3 million years. What was
not said was that the planet has for a significant part of that time
span swung in cycles of 100,000 years from being an ice-ball for 80,000
years and a desert for 20,000 years. At the present time we are about
half-way through a warm part of the cycle. So why is there all this
concern about CO2?

Nonsense! We have been cooling for the last 6000 years. We were heading for a new glacial period, but now we are heading for the climate of the Pliocene when sea levels were 25 m higher and CO2 was at 400 ppm.
Just can't trust the BBC....
If CO2 continues to increase at the current rate of 3 ppm per year, then by 2100 CO2 will be at about 600 ppm and all the ice sheets will have gone leading to a sea level rise of 65 m, with a climate to match.
How much of London, Portsmouth, Southampton, Plymouth, Bristol, Cardiff, Swansea, Liverpool, Glasgow, Aberdeen, Dundee, Newcastle, Hull, or Cambridge at 5 m asl will be left after that?
When the temperature falls, there is little help from CO2 levels
remaining high, so what do you propose as the mechanism for your claimed
halt of the temperature drop that you mentioned?

My science does not come from the BBC. It comes from the scientific literature, e.g. https://science.sciencemag.org/conte.../6124/1198.ppt Which blog do you get yours from?

More nonsense. When the temperature drops water vapour decreases and CO2 becomes the main greenhouse gas.

On 15/09/2020 10:27, Alastair B. McDonald wrote:
On Tuesday, 15 September 2020 at 10:04:51 UTC+1, Spike wrote:
On 14/09/2020 16:21, Alastair B. McDonald wrote:
On Monday, 14 September 2020 at 11:28:45 UTC+1, Spike wrote:
On 14/09/2020 08:28, Graham Easterling wrote:

it's been allowed to continue. It was always going to be difficult to get Countries to reduce carbon emissions. The economic crash of 2008 made an attempt but of course, governments were having none of that. Important steps were taken to boost car production & get CO2 emissions back on track.

In a recent BBC R4 news programme, it was claimed that CO2 levels are
higher now than than at any time in the last 3 million years. What was
not said was that the planet has for a significant part of that time
span swung in cycles of 100,000 years from being an ice-ball for 80,000
years and a desert for 20,000 years. At the present time we are about
half-way through a warm part of the cycle. So why is there all this
concern about CO2?

Nonsense! We have been cooling for the last 6000 years. We were heading for a new glacial period, but now we are heading for the climate of the Pliocene when sea levels were 25 m higher and CO2 was at 400 ppm.

Just can't trust the BBC....

If CO2 continues to increase at the current rate of 3 ppm per year, then by 2100 CO2 will be at about 600 ppm and all the ice sheets will have gone leading to a sea level rise of 65 m, with a climate to match.
How much of London, Portsmouth, Southampton, Plymouth, Bristol, Cardiff, Swansea, Liverpool, Glasgow, Aberdeen, Dundee, Newcastle, Hull, or Cambridge at 5 m asl will be left after that?

When the temperature falls, there is little help from CO2 levels
remaining high, so what do you propose as the mechanism for your claimed
halt of the temperature drop that you mentioned?

My science does not come from the BBC.

I merely quoted what the BBC said, and asked a question based on what
they didn't say in their news item.

It comes from the scientific literature, e.g. https://science.sciencemag.org/conte.../6124/1198.ppt Which blog do you get yours from?

"Access Denied. You are not authorized (sic) to access this page"

More nonsense. When the temperature drops water vapour decreases and CO2 becomes the main greenhouse gas.

So we should be worried about water vapour rather than CO2. At what
level of water vapour does the crossover take place? How does that
relate to temperature?

--
Spike

On Tuesday, 15 September 2020 at 11:53:06 UTC+1, Spike wrote:
On 15/09/2020 10:27, Alastair B. McDonald wrote:

In a recent BBC R4 news programme, it was claimed that CO2 levels are
higher now than than at any time in the last 3 million years. What was
not said was that the planet has for a significant part of that time
span swung in cycles of 100,000 years from being an ice-ball for 80,000
years and a desert for 20,000 years. At the present time we are about
half-way through a warm part of the cycle. So why is there all this
concern about CO2?

Nonsense! We have been cooling for the last 6000 years. We were heading for a new glacial period, but now we are heading for the climate of the Pliocene when sea levels were 25 m higher and CO2 was at 400 ppm.

Just can't trust the BBC....

If CO2 continues to increase at the current rate of 3 ppm per year, then by 2100 CO2 will be at about 600 ppm and all the ice sheets will have gone leading to a sea level rise of 65 m, with a climate to match.
How much of London, Portsmouth, Southampton, Plymouth, Bristol, Cardiff, Swansea, Liverpool, Glasgow, Aberdeen, Dundee, Newcastle, Hull, or Cambridge at 5 m asl will be left after that?

When the temperature falls, there is little help from CO2 levels
remaining high, so what do you propose as the mechanism for your claimed
halt of the temperature drop that you mentioned?

My science does not come from the BBC.
I merely quoted what the BBC said, and asked a question based on what
they didn't say in their news item.
The BBC was just making one point - that CO2 levels are now where they were before the Pleistocene period began 3,000,000 years ago. Then the level dropped below 400 ppm and this ice age began. The ice age consists of glacial periods and interglacial, driven by the Milankovitch. Cycles in the Earth’s orbit. So the climate is not just affected by CO2. It is also affected other things such as solar radiation and water vapour.

Currently we are living in the Holocene interglacial which peaked 6000 years ago.
It comes from the scientific literature, e.g. https://science.sciencemag.org/conte.../6124/1198.ppt Which blog do you get yours from?
"Access Denied. You are not authorized (sic) to access this page"

Try this http://www.realclimate.org/images//Marcott.png from the same paper

More nonsense. When the temperature drops water vapour decreases and CO2 becomes the main greenhouse gas.
So we should be worried about water vapour rather than CO2. At what
level of water vapour does the crossover take place? How does that
relate to temperature?

At 0C water vapour is insignificant. So over the ice sheets CO2 is the main greenhouse gas. That is why the Arctic is warming three times faster than elsewhere. Gehenna the sea ice melts water vapour will take over and the NH warm even faster!

On 15/09/2020 17:49, Alastair B. McDonald wrote:
On Tuesday, 15 September 2020 at 11:53:06 UTC+1, Spike wrote:

I merely quoted what the BBC said, and asked a question based on what
they didn't say in their news item.

The BBC was just making one point - that CO2 levels are now where they were before the Pleistocene period began 3,000,000 years ago. Then the level dropped below 400 ppm and this ice age began. The ice age consists of glacial periods and interglacial, driven by the Milankovitch. Cycles in the Earth’s orbit. So the climate is not just affected by CO2. It is also affected other things such as solar radiation and water vapour.

Currently we are living in the Holocene interglacial which peaked 6000 years ago.
It comes from the scientific literature, e.g. https://science.sciencemag.org/conte.../6124/1198.ppt Which blog do you get yours from?

Try this http://www.realclimate.org/images//Marcott.png from the same paper

Whenever I see 'HadCrut' I think of Clmategate.

More nonsense. When the temperature drops water vapour decreases and CO2 becomes the main greenhouse gas.

So we should be worried about water vapour rather than CO2. At what
level of water vapour does the crossover take place? How does that
relate to temperature?

At 0C water vapour is insignificant. So over the ice sheets CO2 is the main greenhouse gas. That is why the Arctic is warming three times faster than elsewhere. Gehenna the sea ice melts water vapour will take over and the NH warm even faster!

That makes no logical sense whatsoever. Would you care to explain your
thinking?

Gehenna the sea ice melts water vapour will take over and the NH warm even faster!

That doesn't parse very well either.

--
Spike

On Thursday, 17 September 2020 at 09:21:00 UTC+1, Spike wrote:

Whenever I see 'HadCrut' I think of Clmategate.

Whenever I see Climategate I think of a scientist suffering from the timewasting tactics of a climate change denier.


More nonsense. When the temperature drops water vapour decreases and CO2 becomes the main greenhouse gas.

So we should be worried about water vapour rather than CO2. At what
level of water vapour does the crossover take place? How does that
relate to temperature?

There is no crossover point. At 0C there is virtually no water vapour (WV) and so the WV greenhouse effec is virtually nil, and the greenhouse effect depends on the CO2 concentration. As the temperature rises the concentration of water vapour increases until its effect overtakes CO2 and eventually it dominates, as it does in the tropics at sea level.

Note we are talking about local surface temperature, not global temperature.. Thus in the tropics, the snow-capped peak of Kilimanjaro is melting primarily because of the effect of increased CO2, not because the region is warming.

At 0C water vapour is insignificant, so over ice sheets CO2 is the main greenhouse gas. That is why the Arctic is warming three times faster than elsewhere. When the Arctic sea ice melts completely water vapour will take over the greenhouse effect and the NH will warm even faster!

Water vapour is part of a positive feedback loop. When the surface temperature rises (because of increased CO2) then more water is evaporated and water vapour increases. This raises the air temperature even further and produces more water vapour. This runaway effect only ends when enough of the water vapour condenses forming clouds which reflect away the incoming solar radiation.

When the Arctic sea ice has melted, water vapour will take over the greenhouse effect and the NH will warm even faster!

To sum it all up, CO2 concentration is not the only thing that affects global temperature. Solar radiation and ithe albedo from ice sheets and clouds play a major role. But the later depend on water vapour which depends on CO2.

HTH, Alastair.

In article ,
says...
At 0C water vapour is insignificant, so over ice sheets CO2 is the main greenhouse gas. That is why the Arctic is warming three times faster than elsewhere. When the Arctic sea ice melts completely water vapour will take over the greenhouse effect and the NH will warm even faster!


Not making sense here. You are saying the Arctic is warming 3 times
faster than elsewhere because there is no WV forcing in the Arctic (it's
all CO2 forcing).

Then you are saying that once there is WV forcing it will warm even
faster.



--
Alan LeHun

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On Thursday, 17 September 2020 at 14:54:36 UTC+1, Alan LeHun wrote:
Not making sense here. You are saying the Arctic is warming 3 times
faster than elsewhere because there is no WV forcing in the Arctic (it's
all CO2 forcing).

Then you are saying that once there is WV forcing it will warm even
faster.

What I am saying is that the greenhouse effect from water vapour is saturated in the tropics. Any increase in CO2 has very little effect there because the temperature has already been maxed out by the water vapour producing clouds. Of course it is more complicaed than that because there are no clouds in parts of the sub tropics e.g. the Sahara Desert, and clouds can be produced by orography not just convection.

In the cryosphere there is, in effect, no water vapour until the ice melts, so the warming is due to CO2. However, once the ice melts the positive feedback from water vapour will kick in and temperatures will soar as they did at the start of the Holocene (end of the Younger Dryas) when the sea ice in the GIN (Greenland, Iceland, and Norwegian ) Seas disappeared. See

https://cdn.britannica.com/s:1500x70...s-addition.jpg

Note the ice concentration on that diagram is land ice produced by snow from water vapour evaporated from the ice free GIN Seas.