Natural Climate Cycles

Twentieth Century warming was nothing unusual. Climate is cyclic, and there are cycles within cycles. The graph below, based on reconstruction from the geologic record, shows that there have been several cycles of warming and cooling since the end of the last glacial epoch. The temperature during the Holocene Climate Optimum was 3ºF to 10ºF warmer than today in many areas.


Evidence for these cycles is found in the ice cores from Greenland and Antarctica, in fossil pollen records, in cores of sediments taken beneath lakes and the ocean, in the distribution of glacial deposits, in the analysis of stalagmites in caves, and in the historic record. These records also show that the cycles were global events.

It is still unclear why these cycles occur at the intervals they do. Some researchers say it’s a combination of solar cycles which periodically reinforce each other both positively and negatively.

For most of the history of this planet, atmospheric carbon dioxide levels were more than 10 times the current level. For most of the last 250 million years carbon dioxide levels were more than three times the current level.

Climate alarmist claims that our carbon dioxide emissions could trigger runaway global warming is pure nonsense. It if could happen, it would have happened already. Run-away warming cannot happen on this planet because Earth is a water world. Warming increases evaporation. Water vapor, and its latent heat, is carried aloft by convection. Heat is lost to space when the water vapor condenses. The condensation also produces clouds which reflect incoming solar radiation. That is Earth’s negative feedback mechanism to prevent run-away warming.


Dansgaard, W. , et al., 1969, One Thousand Centuries of Climatic Record from Camp Century on the Greenland Ice Sheet, Science 17 Vol. 166. no. 3903.

Friis-Christensen, E. And Lassen, K., 1999, Length of Solar Cycle: An Indicator of Solar Activity Closely Associated with Climate, Science 254.

Hu, F.S. et al., 2003, cyclic Variation and Solar Forcing of Holocene Climate in the Alaskan Subarctic, Science 301.

Niggerman, S., et al., 2003, A Paleoclimate Record of the last 17,000 Years in Stalagmites from the B7 Cave, Sauerland, Germany, Quaternary Science Reviews 22.

Pisias, N.G. et al., 1973, Spectral analysis of Late Pleistocene-Holocene Sediments, Quaternary Research, March 1973.

Schönwiese, Christian, 1995, Klimaänderungenaten, Analysen, Prognosen.-224 S.ISBN: 978-3-540-59096-5.

Viau, A.E. et al., 2002, Widespread Evidence of 1,500-yr Climate Variability in North America during the Past 14,000 Years, Geology 30.


  1. Do you mean to say that it has nothing at all to do with carbon dioxide emissions due to the beef industry in Argentina?

  2. Who said alarmists assimilated facts?    Generally they ignore facts and instead rely on innuendo, half-truths, falsehoods, extreme extrapolations, and stories published in newspapers other than the Citizen.

  3. The heat increases during the Holocene era were not accidental.  It was caused by carbon emmissions from the irresponsible driving habits of turtles.  At the objection of mammoths, they insisted on wasting resources and driving Hummersl.  As punishment they were vanished to the Galapagos Islands to suffer for their sins by swimming in guano.

  4. Your arguments would carry more weight if you weren’t so obviously an apologist for business interests. 

  5. Yes, I admit that I favor Capitalism and Free Enterprise over Socialism and the nanny state.

  6. And by the way, Leftfield, your comments would hold more weight if you countered with facts rather than Ad Hominem epithets

  7. Leftfield just doesn’t want to be confused by the facts – obviously his mind is made up.

  8. I guess even in this new incarnation of the Citizen you’ll publish anyone with an opinion… for to confuse this opinion with science is a travesty. It’s not so hard to hear the economist trump the geologist.
    Please try again. (oh, and you guys should get a new graph… that one’s awfully tired, dontcha think?)

  9. Well, it’s true that I have an agenda.  But I’m honest and up front about it.  I could quote a whole line of articles by scientists of a socialist bent with their own supporting graphs and charts showing how neoliberalism and globalization are incompatible with any sort of  ecological sustainability.  They do exist; I read them from time to time and they are very persuasive.  But I don’t do this because it is unlikely to be convincing in this context , with this crowd, and also because I have some training in science and I know better than to get my information about scientific progress from sources pushing a political agenda of any kind (this includes the mainstream media; especially the mainstream media).

    Therein lies the difference.  I believe your primary loyalty is to the status quo vis a vis the current power structure, and not necessarily to a search for the truth.   


  10. “Yes, I admit that I favor Capitalism and Free Enterprise over Socialism and the nanny state.”

    Well, I favor democracy, equality and a government that represents the interests of the citizens over exploitation, racism and a government whose interest lies in ensuring the welfare of capital.

    You feel compelled to expose what you believe is the truth about global warming and I feel compelled to speak out against reactionary politics.  This is what we have in common.

  11. Practical Ecologist,

    Your comments are confusing.  What do you think the facts are?  And can you back them up with empirical evidence?

  12. It may have escaped your notice that I provide references to the scientific literature to back up my posts.

    As for neoliberalism, globilization and ecological susainability, that’s piling it too deep.  As far as “some training in science” — a little knowledge is a dangerous thing.

  13. While the likes of you both — Jonathan DuHamel and leftfield — are busy pissing on each others’ ideologies and agendas, the rest of us are at risk of missing out on a unique opportunity to make this country environmentally cleaner, more economically sound and less energy dependent. Nit pick all you want but mankind only seems to respond to crisis and if we truly want progress in those areas, the time to move is right now. However one must sell that concept, as long as it gets done; who cares what each of you thinks.

  14. you losers need to get lives. stop using big words and being all sophisticated and fancy. global warming is human caused- get over it!!

Comments are closed.