Question about climate change

[Reality Check]

Wanna see some more clearly weaponized graphs?

A clearly misunderstood graph, Hercules56. There cannot be measurements at a location before the instruments at the location existed!

Measurements of CO2 concentration at Mauna Loa (the Keeling Curve) started in 1958.

In 1957-1958, the International Geophysical Year, Keeling obtained funding from the Weather Bureau to install infrared gas analyzers at remote locations, including the South Pole and on the volcano of Mauna Loa on the island of Hawaii.

There were measurements of CO2 concentration at other locations and previously.
There are reconstructions of CO2 concentration using ice cores that go back hundreds of thousand of years.

 

[Hercules56]

delete

 

[Pixel42]

https://www.carbonbrief.org/factche...es-say-about-past-and-present-climate-change/

 

[Hercules56]

Seems 2,000 years is not a good barometer for temp increases, as avg Antarctic temps clearly were higher than today, many times before 2,000 years ago.

 

[GlennB]

Hercules56, any chance you could learn how to size an image so it fits on the screen? Cheers!

 

[Hercules56]

Hercules56, any chance you could learn how to size an image so it fits on the screen? Cheers!

I would love to. I am uploading the images to this forum and then pasting images to posts. Please PM instructions how to shrink images. Thanks.

 

[Skeptical Greg]

Hercules56, any chance you could learn how to size an image so it fits on the screen? Cheers!

Who's screen?

Looks just fine on mine..

A source for the image would be much more useful.

 

[Hercules56]

Who's screen?

Looks just fine on mine..

A source for the image would be much more useful.

https://www.carbonbrief.org/factche...es-say-about-past-and-present-climate-change/

 

[Pixel42]

Seems 2,000 years is not a good barometer for temp increases, as avg Antarctic temps clearly were higher than today, many times before 2,000 years ago.

[qimg]http://www.internationalskeptics.com/forums/picture.php?albumid=1446&pictureid=13627[/qimg]

Global temperature was higher 4000 - 8000 years ago because the current interglacial peaked about 6000 years ago. It's been gradually reducing since then - well it was until very recently.

BTW I assume the highlighted should be Arctic, not Antarctic.

On the subject of the Antarctic:

http://nsidc.org/arcticseaicenews/

Arctic sea ice continues to decline at a near-average pace, with ice extent twelfth lowest in the satellite record at this time. Antarctic sea ice by contrast is growing at far below-average rates and is at an unprecedently low level for this time of year relative to the 45-year data set.

 

[Hercules56]

Seems 2,000 years is not a good barometer for temp increases, as avg Antarctic temps clearly were higher than today, many times before 2,000 years ago.

[qimg]http://www.internationalskeptics.com/forums/picture.php?albumid=1446&pictureid=13627[/qimg]

Graph suggests world avg temps were warmer 2,500 years ago than today. Wasn't that when African civilizations were at their peak of power? Of course this warmer period was not due to higher CO2, but more sunlight.

 

[Hercules56]

Persian, Greek, Egyptian, Babylonian Empires all flourished during the BC era when avg global temps were warmer than today.

Response? Is climate change due to Milankovitch Cycles easier to tolerate than due to unnatural increase in CO2 and deforestation?

 

[Skeptical Greg]

" Easier " Is relative.

Those BC era empires were not the concrete jungles and urban sprawls we enjoy today.

Then, and now, we really have no immediate choice but to tolerate it as best we can, with the resources we have.

People everywhere are sitting in their air conditioned homes, watching and listening to the media telling them how horrific it all is.

 

[Pixel42]

Climate change is easier to tolerate when (a) it's small and gradual rather than big and rapid and (b) there are only about 100 million people on the planet needing to be fed and housed.

 

[Roger Ramjets]

" Easier " Is relative.

Those BC era empires were not the concrete jungles and urban sprawls we enjoy today.

Those BC era empires didn't have the knowledge and technology that we enjoy today.

Then, and now, we really have no immediate choice but to tolerate it as best we can, with the resources we have.

A tautology. We can do a lot better with the resources we have than we are doing.

People everywhere are sitting in their air conditioned homes, watching and listening to the media telling them how horrific it all is.

Not everywhere. Air conditioning use is more related to affluence than need.

Percentage of homes with air conditioning:-

United States 90%
Japan 89%
China 60%
Mexico 16%
Brazil 16%
Indonesia 9%
India 7%

India, Indonesia and Mexico get a lot hotter than China, Japan and the US, yet their air conditioning usage is much lower. We better hope people in those hot countries stay poor, or we're really in trouble!

 

[Skeptical Greg]

I think you made my point.
Thanks.

 

[lomiller]

Graph suggests world avg temps were warmer 2,500 years ago than today.

It shows no such thing. It's a graph pf Greenland Temperatures, not global temperature.

Current global temperatures are clearly much higher than any time in the past 2500 years and may have already passed the Holocene maximum from ~6000-8000 years ago. (We are near the top of the 95% range for the warmest reconstructions)

Of course this warmer period was not due to higher CO2, but more sunlight.

Nope. Variations in sunlight are far to small to explain the earths climate history. Rather, what happens is changes in how sunlight gets distributed cause the earth to release or absorb CO2 which then serves as the primary driver of global temperature changes.

 

[Roger Ramjets]

I think you made my point.
Thanks.

Not sure what your point is.

 

[lomiller]

Persian, Greek, Egyptian, Babylonian Empires all flourished during the BC era when avg global temps were warmer than today.

Nope, see above.

Response? Is climate change due to Milankovitch Cycles easier to tolerate than due to unnatural increase in CO2 and deforestation?

Global temperatures are rising a full order of magnitude faster than anything seen in 65 million years. Current rate of increase is ~40 X faster than during the last de-glaciation. Ecosystems and animals can adapt and migrate when changes are slower, but when it takes thousands of years to turn Taiga into soils that can support more complex ecosystems plants an animals, or agriculture migrating on a scale of 200 years is impossible.

 

[Pixel42]

Nope. Variations in sunlight are far to small to explain the earths climate history. Rather, what happens is changes in how sunlight gets distributed cause the earth to release or absorb CO2 which then serves as the primary driver of global temperature changes.

For completeness: AIUI the carbon dioxide feedback is one of three positive feedbacks which amplify the effect of climate forcings such as the Milankovic cycles. The other two are another greenhouse gas - water vapour - and ice albedo.

 

[lomiller]

For completeness: AIUI the carbon dioxide feedback is one of three positive feedbacks which amplify the effect of climate forcings such as the Milankovic cycles. The other two are another greenhouse gas - water vapour - and ice albedo.

Water vapor is a short term feedback. It amplifies all warming and cooling effects but it's only active over a matter of days or weeks so it doesn't really play much role in long term climate change.

Ice albedo plays a roll, but it takes a lot of energy to melt ice so you need to have sustained warming over a fairly long period of time for it to kick in. Eg the period 125KYA was ~3 deg warmer than 1900. We may hit those levels soon, but it would still take 10-20 decades to see the type of melting in the Greenland and West Antarctic ice sheets that accompanied those 3 degrees of warming.

That's one of the dangers of climate change, we don't see all the ill effects immediately. If we hit 3 deg over early 1900 temperatures it effectively locks us into to 20 feet of sea level rise, but it would still take 100-200 years for that to happen.

Anyway, CO2 plays a special role in long term climate change as it's both strong and persistent in the environment so it's in the sweet sport as the major player in the earths long term climate. It's sometimes said that it takes 100-200 years for fossil CO2 the be absorbed by the earths ecosystems, but that's not entirely true either. ~10% of the CO2 humans are emitting will still be causing elevated global temperatures 100K years from now.