After reading the article, I was inspired to post the following comment, and this led to a rambling, polite discussion over a couple of days with Dr Scott Denning, Monfort Professor of Atmospheric Science, Colorado State University, and occasionally less polite discussions with a couple of other commenters.
My opening comment:
Scott Denning's statement about all the heat generated by burning fossil fuels is quite foolish. What does he think caused five periods of greater warming than the current one in the past 11,000 years since the end of the last Ice Age? More recently, 39 of the 50 states records of hottest days were set over 50 years ago. Coral mounts rising ten feet above current sea levels show that temperature and sea level were much higher 4,000 years ago at the end of the Holocene Climate Optimum. Just 1,000 years ago the global Medieval Warm Peiod was warmer, sea levels were higher, and humanity prospered. We are now coming off the Little Ice Age (1350 to 1850 AD) and the warming we are now experiencing is a natural rebound from the coldest period of the past 11,000 years. If you won't listen to skeptics, lend an ear to the Earth - it tells the story of natural climate change eloquently.
Zippy-1 (the first commenter)
Your logic is flawed. None of your examples negate the 'greenhouse effect' warming caused by rising CO2 levels from humans burning fossil fuels. And 39 states temperature records? Come on. Even if you're correct cherry-picked local examples are meaningless in the context of global average annual temperatures, which puts the most recent decade as the hottest on record. 2010 was tied for the hottest full year on record and the first half of 2011 is a record.
Dr Scott Denning's reply to my comment:
Hi Michael,
Simple question ... simple answer. Earlier climate changes were caused by heat coming into the Earth and heat going out from the Earth. Modern climate change responds to precisely the same physics that past climate changes responded to.
Is there some reason that you think the Earth warmed and cooled in the past when heat was added or subtracted, but that somehow the extra Watts of heat from CO2 "don't count?"
Interesting theory. I guess as a scientist I have to be a bit skeptical of the logic though.
Most of us understand that adding heat to things warm them up. Always has. Always will.
Best regards,
Scott Denning
Monfort Professor of Atmospheric Science
My reply to Dr Denning:
Dr Denning
The portion of additional CO2 created by the burning of fossil fuel is only a tiny part of the CO2 created naturally by oxidation by plants, animals, and decay of plant matter. And in all that, CO2 is only 0.04% of the atmosphere by volume, of which only 3% is produced by human activity. In previous periods of warming, when CO2 was 10 to 20 rimes current levels, the Earth has plunged into ice ages while CO2 was still at high levels. The Holocene Optimum of 8,000 to 4,000 years ago was much warmer than now and followed the Ice Age which ended 11,000 years ago, yet CO2 was much lower. The additional warmth of the Holocene Optimum did not come from burning fossil fuels, just as hundreds of other periods of warming were not caused by increased CO2.
There is now good scientific reason to doubt the existence of a "greenhouse warming effect."
The Monterrey science research institute also recreated Wood’s test into the effect of longwave infrared radiation trapped inside a greenhouse. Unlike Pratt it found that Wood’s findings were correct, absolutely valid and systematically repeatable. The Bio Cab man affirms, “ the greenhouse effect does not exist as it is described in many didactic books and articles.”A closing point - current warming started 300 years ago
Put simply, one of the aforementioned professors has their reputation perilously on the line and Nahle is gunning for an explanation from his U.S. Rival. A clue to the outcome: Pratt isn't even qualified in science - he's a (warmist) mathematician specializing in computers.
Professor Nahle’s findings will come as no surprise to anyone who is up to speed with the other big climate story that has raised huge doubts over any so-called greenhouse effect. NASA now admits global warming just isn’t happening despite ever-rising levels of CO2.
Laughably, the once illustrious U.S. space agency is blaming no warming this century on China."
My reply to Zippy-1:
"39 of the 50 states records of hottest days were set over 50 years ago."
Zippy-1
These are not cherry-picked. I simply googled heat records by state and found a table from USA Today. The initial reason I did this was because Al Gore and His Acolytes have now adopted a new appoach to alarmism by claiming all severe weather events are evidence of man-caused climate change. Kevin Trenberth also has made this claim. As far as this being the hottest period on record, I noted in a previous post that Greenland ice cores for the past 10,000 years show that not one of the past 100 years were warmer than 9,100 of the past 10,000. So much for exceptional warmth.
Current warming is "unprecedented" only if you think climate began after Al Gore earned his D's at Harvard.
The next reply from Dr Scott Denning
Good morning Michael,
I asked you why past climate changes can be explained by changes in heating, and you replied that there isn't much CO2 in the atmosphere. (Note: that's what I said and it's true; CO2 is only 0.0387% by volume) Then you said most CO2 doesn't come from combustion. (Note: that's also true, since 96% of CO2 is produced by natural, not human sources)Then you claimed the greenhouse effect doesn't exist (Note: this is not exactly true, since I only provided quotes from the scientists that say the greenhouse effect doesn't exist.
I'll ask you again: if changes in heating produced ice ages and warm periods in the past as you mention, why on Earth do you expect extra watts of heat from CO2 to have no effect now? Have the laws of thermodynamics changed? (Note: thousands of times in the past cooling began when CO2 was high; enormous quantities of CO2 were being added to the atmosphere from the warming seas and from decay - that's oxidation - of vegetable matter, and heat is heat)
We don't expect global warming because 39 states are hot today. We expect global warming because adding heat to things changes their temperature. Don't believe me? Put a pot of water on the stove and see what happens! (Note: conversely, we expect global cooling when the orbital dynamics that caused global warming are reversed)
Have a great day,
Scott Denning
My reply to Dr Denning:
Where did all the extra heat come from when the temperatures were much higher five times in the past 10,000 years since the end of the Ice Age than they are now? CO2 was much lower then. In fact, even now it is close to its lowest level in parts per million going back about a billion years. Several things are undeniable: CO2 levels have been over ten times current atmospheric levels previously without causing run-away warming; in all instances, warming began before CO2 increased, and cooling began when CO2 was high and before it started dropping; CO2 and the rest of the atmosphere is warmed by convection, just as trapped air in a greenhouse is - unlike a greenhouse, the warm air rises and mixes with the cooler air above; CO2 has neither the volume nor properties to cause a difference in temperature to the point that it could be distinguished from natural environmental noise.
A thought I am now developing is that the current production of heat by the Earth is very small compared to periods when plants grew, died, decomposed to form huge deposits of coal and oil, and along the way emitted enormous quantities of CO2 - which further fed plant growth. Of course, the same is happening today, only the naturally produced CO2 is much less because the plant mass is so much smaller, although it is over thirty times what is produced by human activity.
A comment from Elmer Jones:
I haven't heard anyone explain why the earth's glaciers are melting at a pronounced rate according to those that have studied them . I give little weight to those people whom have not studied them. Where did the North polar ice cap go?
Why is the Greenland ice cap melting at an advanced rate? If heat is being generated internally by the planet then what is the cause? There is too much body of evidence to prove that "yes indeed the ice deposits are melting."
My reply to Elmer Jones:
A map of Glacier Bay, Alaska, shows glacier retreat of 60 miles from 1760 to 1912, and only about six miles since. Glacier retreat and advance during the past 11,000 years since the last Ice Age has been extensively studied and documented by such climate experts as H H Lamb, "Climatic History and the Future", and the founder of the Climatic Research Unit of the University of East Anglia, now famous for its role in Climategate. A study of glacier history shows glaciers are not now retreating at an advanced rate, and neither is the Greenland ice cap. In fact, Greenland ice cores show that Greenland was warmer for 9,100 years of the past 10,000 than for any year of the past 100. Glaciers in the Alps retreated further 1,000 years ago during the Medieval Warm Period than during the recent warming. The Alpine glaciers advanced during the Little Ice Age (1350 to 1850 AD) then began retreating over 100 years before significant increases in atmospheric CO2. Current retreat is uncovering man-made artifacts that were created during the Medieval Warm Period, then covered during the Little Ice Age, and are now being exposed again. Russian Arctic studies have determined there were several periods in the past 11,000 years since the last Ice Age when there was less Arctic ice than now, particularly during the much warmer Holocene Climate Optimum when it was so much warmer than present that sea levels were over ten feet higher than now at the peak of Holocene warming about 4,000 years ago. There are coral mounts ten feet higher than the current sea level that prove it was much warmer and sea levels were higher then - corals don't grow out of the water, you know, and they grow particularly well in warm water. I hope I answered your questions, Elmer. This information, and a lot more, is written clearly in the Earth for all to see that seek it with open minds and scientific curiosity.
Then I passed this reply on to Dr Denning:
Some more musings about current natural climate change. Where did the heat come from over 200 years ago when CO2 was low?
A map of Glacier Bay, Alaska, shows glacier retreat of 60 miles from 1760 to 1912, and only about six miles since. Glacier retreat and advance during the past 11,000 years since the last Ice Age has been extensively studied and documented by such climate experts as H H Lamb, "Climatic History and the Future", and the founder of the Climatic Research Unit of the University of East Anglia, now famous for its role in Climategate. A study of glacier history shows glaciers are not now retreating at an advanced rate, and neither is the Greenland ice cap. In fact, Greenland ice cores show that Greenland was warmer for 9,100 years of the past 10,000 than for any year of the past 100. Glaciers in the Alps retreated further 1,000 years ago during the Medieval Warm Period than during the recent warming. The Alpine glaciers advanced during the Little Ice Age (1350 to 1850 AD) then began retreating over 100 years before significant increases in atmospheric CO2. Current retreat is uncovering man-made artifacts that were created during the Medieval Warm Period, then covered during the Little Ice Age, and are now being exposed again. Russian Arctic studies have determined there were several periods in the past 11,000 years since the last Ice Age when there was less Arctic ice than now, particularly during the much warmer Holocene Climate Optimum when it was so much warmer than present that sea levels were over ten feet higher than now at the peak of Holocene warming about 4,000 years ago. There are coral mounts ten feet higher than the current sea level that prove it was much warmer and sea levels were higher then - corals don't grow out of the water, you know, and they grow particularly well in warm water. This information, and a lot more, is written clearly in the Earth for all to see that seek it with open minds and scientific curiosity.
Then I replid to Zippy-1:
"Your logic is flawed. None of your examples negate the 'greenhouse effect' warming caused by rising CO2 levels from humans burning fossil fuels."
Your logic is flawed. Current warming began over 100 years before human activity caused any significant increase in CO2 levels. The Little Ice Age ended by 1850 or earlier, and there were two periods of much more rapid warming than now from 1850 to 1945. Ironically, as CO2 increased steadily after 1950, there was a cooling period that lasted until 1975, then warming, then cooling the past decade.
And I further reply to Zippy-1:
Concerning "hottest on record" temps, if you go to: http://climvis.ncdc.noaa.gov/cgi-bin/cag3/hr-display3.pl (which is a government website) you will see a chart of contiguous US temperatures for the past 115 years which show an increase of about 1.2 degrees Fahrenheit during that period, roughly half before 1950 and half after. This NOAA chart also shows no warming for 12 years, and that 2009 and 2010 were the lowest annual temperatures since 1994. As far as a decade being the hottest on record, you are lucky science can't break out any but the most recent warm periods by decade. Suffice it to say, since Greenland ice cores show 9,100 of the past 10,000 years were warmer than any of the past 100, there were centuries 4,000 to 8,000 years ago that were hotter than the past decade.
Then Dr Denning replied to me:
Michael,
The Earth's surface receives virtually all of its heat from only two sources: incoming radiant energy from the Sun and from the warm air above us. Believe it or not, almost two-thirds of the total comes from the air. This is easily measured by comparing the total energy in at night to that during the day. It's not in dispute. Energy leaving the surface is mostly through radiant energy as well, with about 20% going up as convective heat transfer and evaporative cooling.
Whenever more heat comes in than goes out, the Earth's surface warms up. Whenever more heat goes out than comes in, the Earth's surface cools off. This is what explains the difference between day and night, summer and winter, Miami and Minneapolis. Pretty simple.
In fact, this simple physics also explains EVERY CLIMATE CHANGE THE EARTH HAS EVER EXPERIENCED. So all of your examples of warmer and colder periods in the past, the Little Ice Age, the Big Ice Age, the Age of the Dinosaurs, everything.
Precisely the same physical laws also govern the changes that will certainly occur if the amount of radiant energy delivered to the Earth's surface increases by 8 Watts per square meter when China and India build modern industrial economies using coal.
Look, I'm not selling something smelly here: adding heat warms things up. Removing heat cools things off. That's how climate has worked for billions of years. That's how it will continue to work for the rest of our children's lives.
I do appreciate your interest in the science. Contrary to your original comment, there's nothing foolish about this!
Sincerely,
Scott Denning
Monfort Professor of Atmospheric Science
Colorado State University
I persist in disagreeing with Dr Denning:
Where did the heat come from over 200 years ago when CO2 was low?
A map of Glacier Bay, Alaska, shows glacier retreat of 60 miles from 1760 to 1912, and only about six miles since. Glacier retreat and advance during the past 11,000 years since the last Ice Age has been extensively studied and documented by such climate experts as H H Lamb, "Climatic History and the Future", and the founder of the Climatic Research Unit of the University of East Anglia, now famous for its role in Climategate. A study of glacier history shows glaciers are not now retreating at an advanced rate, and neither is the Greenland ice cap. In fact, Greenland ice cores show that Greenland was warmer for 9,100 years of the past 10,000 than for any year of the past 100. Glaciers in the Alps retreated further 1,000 years ago during the Medieval Warm Period than during the recent warming. The Alpine glaciers advanced during the Little Ice Age (1350 to 1850 AD) then began retreating over 100 years before significant increases in atmospheric CO2. Current retreat is uncovering man-made artifacts that were created during the Medieval Warm Period, then covered during the Little Ice Age, and are now being exposed again. Russian Arctic studies have determined there were several periods in the past 11,000 years since the last Ice Age when there was less Arctic ice than now, particularly during the much warmer Holocene Climate Optimum when it was so much warmer than present that sea levels were over ten feet higher than now at the peak of Holocene warming about 4,000 years ago. There are coral mounts ten feet higher than the current sea level that prove it was much warmer and sea levels were higher then - corals don't grow out of the water, you know, and they grow particularly well in warm water. This information, and a lot more, is written clearly in the Earth for all to see that seek it with open minds and scientific curiosity.
And Dr Denning replies:
You've asked where the heat came from 200 years ago when we began warming from the Little Ice Age. You've also told me to look at the Earth for answers. Fine. Notice that there's no need to yell at me or insult me. I'm being pretty reasonable and answering you politely.
Regarding the warming that began at the end of the Little Ice Age the answer is the Sun. The warming actually began more like 300 years ago following a period when the sun dimmed by about 1 Watt per square meter (compared to 1367 Watts per square meter today) during the Maunder Minimum. As the sun gradually brightened, even that tiny change (1 W out of 1367) steadily warmed the Earth's climate and produced all those changes you wrote about.
Regarding listening to the Earth, I've been doing it professionally for almost 30 years now. My undergraduate degree was in geology and I used to work in the oil industry. I'm not the crackpot socialist you might imagine! Paleoclimate has always been fascinating to me and I've read thousands of pages of that material over half my lifetime.
Natural climate change shows us a very clear picture of the response of the Earth to changes in the amount of energy coming in and going out. During the last Ice Age 18,000 years ago ice sheets covered much of North America, Europe, and Asia which made the albedo much higher so that sunlight was reflected to space. Cold oceans and fertilization by iron in dust at that time allowed the oceans to dissolve nearly 1/3 of all the CO2 in the air. Together the brighter surface and lower CO2 levels reduced the energy input by about 7.5 Watts per square meter (7.5 times as much as the Little Ice Age). And the changes persisted much longer, allowing climate to cool drastically.
By the time my children are old, Earth's surface will receive 8 Watts per square meter more energy than it did in 1800 (if India and China go big for coal). Do you see why I'm concerned?
Sincerely,
Scott Denning
Again I respond to Dr Denning
Thank you for your replies. I won't SHOUT AT YOU or write insulting things (some pointed comments in this thread are addressed to a Zippy-1), although physics I've learned has convinced me that a colder object (air) does not warm a warmer one (earth), or a smaller one (air) a massive one (ocean), The air does not have the mass to contain heat sufficient to provide two-thirds of warming. On a contrary note, the Sun warms the earth, and after sundown the earth warms the air. My sense of touch confirms this daily.
Of course, increasing levels of CO2 only correlate with temperature 22% of the time, and as Kevin Trenberth said, it's a travesty that the current lack of warming can't be explained. That is why China aerosols have been plugged in to explain the lack of warming, even as the aerosols are due to the enormous quantities of coal the Chinese are burning. Aerosols seem to be a wild card, played when the climate models don't add up.
I have no concern for my grandchildren in a warming world. As Bjorn Lomborg suggests, "Cool it" and adapt. Adaptation has been the genius of humanity for thousands of years, through much warmer and much colder periods. My reading of H H Lamb's "Climatic History and the Future" makes me welcome the idea of a warmer, higher CO2 environment because of high food production. The lessons of the Little Ice Age, of crop failures and starvation and population displacements, incredibly violent and ruinous storms, horrendous flooding and loss of millions of lives in the Yellow River region of China, flooding and enormous erosion on the coasts of England and the Netherlands, and many more disasters than you would get in a warm climate.
Civilization thrived in recent warm periods. The Holocene Climate Optimum of 8,000 to 4,000 years ago, the Roman Warm Period of 200 BC to 500 AD, the Medieval Warm Period (850 to 1300 AD), and the current warm period following the Little Ice Age. Fear cold, not warm.
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