A Brief History of Ice Ages and Global Warming

Some say we are “nearing the end of our minor interglacial period”, and may in fact be on the brink of another Ice Age. If this is true, the last thing we should be doing is limiting carbon dioxide emissions into the atmosphere, just in case they may have a positive effect in sustaining present temperatures.

11 thoughts on “A Brief History of Ice Ages and Global Warming

  1. You’re kidding, right?  Elevated CO2 levels will only last for a brief period.  (Long in terms of human lifespans, nothing in terms of a 100ky glaciation cycle.)

    If anything it’s possible that the current spike will cause a QUICKER onset of the next ice age.  E.g., by shutting down the Atlantic conveyer.  The CO2 will probably wash out of the atmosphere long before it’s reestablished.  In the meanwhile the colder temperatures will mean snow stays on the ground longer and that will help drive temperatures down.

  2. If anything it’s possible that the current spike will cause a QUICKER onset of the next ice age. E.g., by shutting down the Atlantic conveyer.

    Your statement is unscientific because no experiment can be conducted to falsify it.

  3. First, I urge everyone to please read the informative articles on the following sites – basically every “objection” to global warming has been covered in detail from a scientific perspective many times over, and it amazes me that people like jdoe keep coming back with some new twist on the arguments they’re pushing that there’s no need to do anything about it.

    Now, on the particular subject here, Ill-Considered has a short take on what’s wrong with rapid temperature change – massive extinctions. What jdoe’s story (and linked article) is messing with (one of many typical “denier” stances) is the time-scale. If you look on a scale of millions of years, you find all sorts of things. For instance, CO2 levels at present are quite low compared to the levels during the dinosaur era 100 million or more years ago. Of course temperatures are rather well known to have been much warmer then – dinosaurs even lived in Antarctica (where there were no glaciers). But live evolves and adapts quite readily on that timescale, and it’s pretty far-fetched to be worrying about stuff millions of years ahead of us, so those sort of multi-million-year changes aren’t really much of a concern.

    If you look on a time-scale of tens to hundreds of thousands of years, the “recent” past has been quite cold, and low in CO2, with rather dramatic glaciations of the continents, as this article mentions. Comparing conditions with previous inter-glacial periods we’re not particuarly “overdue” for the next ice age yet, but it certainly would be expected a few thousands years down the road. Life has a harder time adapting to changes at that rate, but present life on our planet has lived through these before, so another glaciation would not be anything particularly new.

    But most people don’t particularly worry about conditions a few thousands years ahead of time; by the year 2450 after all we’ll have starships and be worrying about the “Borg”, not “CO2” :-)

    On time scales of less than a thousand years, and particularly on scales of decades which encompass the life of an individual, in the past climate has been fairly stable, with excursions of perhaps a degree or so in incidents like the “Little Ice Age”. But that is the time-scale at which scientists are saying we are at serious risk, over the next few decades, to the end of the 21st century.

    Doubling CO2 from pre-industrial levels, the typical measure of climate sensitivity, presents the world with a warming most likely 3 times or more the decline during the “Little Ice Age”. And limited the growth to just a doubling will already take heroic efforts! What does that mean? More intense hurricanes, a sharp rise in sea level as the Greenland and some Antarctic glaciers melt, desertification, drying out of continental interiors, more fires, more floods, more massive disasters. If we do nothing, at the least, tens or hundreds of millions of people will die, and then there’s the devastation wreaked on the rest of the planet’s inhabitants.

    Yes, some human beings and some of the rest of the planet’s life will undoubtedly survive through to the next ice age. It’s the interim period we need to really worry about.

  4. More intense hurricanes, a sharp rise in sea level as the Greenland and some Antarctic glaciers melt, desertification, drying out of continental interiors, more fires, more floods, more massive disasters.

    Do you honestly believe these scenarios are possible on the scle of a few decades, say by 2050? Deep down do you really believe it? Do you believe sea level will rise significantly (2 feet or more) by 2050? Do you honestly believe higher temperatures will cause significant increase in desert area (as opposed to the beloved majority opinion that higher temperatures will cause more rain)? Yes, yes, some models predict disproportionately more rain in some areas and disproportinately less in others, but these models are not half-way reliable. They have hundreds if not thousands of adjustable parameters that can be adjusted to predict anything. What else? More fires by some even more far fetched conjecture? OK, maybe more fooding & hurricanes in some areas are possible, but other regions will benefit from warmer climate too, they will see better crops and more food.

    As for what may happen by 2100, I don’t think it’s relevant. I side with Vinge and Kurzweil. I think anything beyond 2050 is equivalent to the far furure when we’ll have starships and be worrying about the “Borg”.

    If we do nothing, at the least, tens or hundreds of millions of people will die, and then there’s the devastation wreaked on the rest of the planet’s inhabitants.

    This is not a scientific statement. This is beating the drums (where did you get the 100 million figure? Far fetched conjecture based on another far fetched conjecture?). People will die whether we “do nothing” or “do something”. It’s a matter of balance and opportunity cost.

  5. The post itself is either a deliberate attempt to mislead or an example of someone who hasn’t been doing their research, but nevertheless somehow thinks they know more than those who have.

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