18 January 2006

A look at global warming

So just what is global warming? Is it that terrible trend since the beginning of the Industrial age, lo these last 200 years? Is mankind set to wipe out life on this planet? Lets take a look at what has happened recently.Courtesy of our friends at NASA.

The big deal 12,000 years ago was a mile thick (in some places) ice sheet extending from the polar regions out across the continents southward in the northern hemisphere and to the southern areas of South America and Africa. Sea levels were way down and the climate was very frigid. What changed that? Yes, global warming. Without global warming we would still be eking out a living in temperate to arctic conditions fighting to try and keep a toehold against the megafauna and *maybe* getting lucky enough to discover agriculture. Homo Neanderthalis and Homo Sapiens (Cromagnon) would still, most likely, be living side-by-side as the Neanderthals were a bit better adapted to the harsher northern climes of southern Europe and the sub-arctic middle East. Cromagnon traveled extensively, however, and would have populated the globe, but the question of a viable agricultural revolution in eras when getting out of winter was problematical would have been difficult. Global warming changed climate conditions, made them more temperate and diminished the specialized climates that Neanderthals had been suited to. Without global warming there most likely would have been no mankind as we know it today, no social revolutions due to agriculture and the higher caloric diet that went with it, and no real worries beyond trying to live out the normal life span and maybe survive to the mid-30s.

And to the worrywarts, busybodies and people spelling gloom and doom do note that since the last ice age it has actually been far *warmer* than it is today. In fact the periodicities of ice ages are a damn worrying thing as they tend to work off of global climactic changes and unknown triggering events.
Again from the folks at NASA.

The trick is that we should really, really want to get out of the trough cycle that the globe is in and steady the climate! Global warming? Survival of mankind? If we *don't* keep global temperatures up then we are unlikely to enjoy the trend of the last several million years.

Courtesy of Chatham College.

Yes, look at that scary trend line for the modern age! And see *exactly* what happens when you squash a graph down, too. Still, these folks are proving the point that the trend of the entire global climate since the end of the Cretaceous is downwards. The expanded near-term global temperatures puts the present day within the normal range for this post-glacial period, far below the inter-glacial highs that normally happen and barely within the normal range for standard temperature highs within the last 2MY. Notice that such distorted graphs as those used by Chatham are an example of how to lie with numbers and graphs. They intend to make one point, however, while their graph, taken in context, shows exactly the opposite.

And the squealing begins with the 'look at the scary upward slope due to levels of carbon dioxide!' That is called an "extrapolation" and it is based on shakey science at best and political science at worst. The answer of current volcanic and hot spot based emissions against past history and climate change is a difficult one, but the evidence is that volcanic emissions do tend to cause global cooling and may be trigger events for glacial periods. Weather data is spurious as records beyond tree rings, varves and ice cores is sparse. What we *do* know is that the global oceanic currents tend to change in a cycle that is not well understood, suddenly shifting large masses of warm and cool water across hemispheres. And while the undersea current movement below South Africa links the worlds oceans, their interactions based on that slow current are also not well understood. So what is that extrapolation based on? Well if you take a mere 100 year trend and extrapolate outwards.... why, yes, mathematically you can do that. Now what is the actual *science* behind that?

There is one final graph to be considered in all of this and that is the global climate change since life appeared on this planet of ours:

Courtesy of Geocraft.com.

And the absolutely lovely thing about this is it also gives carbon dioxide levels against global temperatures! This is the exact thing that everyone is so extremely worried about. Everyone points to it and forecasts gloom, doom and bad hair days. So please, please look at the graph and tell me *exactly* what human-kind's impact will be on global climate. I will give you a minute. Take two.

Take a coffee break.

Need to study some courses? You might try some on vulcanology, paleontology and plate tectonics so you can put how high the continents are riding against time on that graph.


So, you have now taken exactly two aspirin, one cup of coffee and decided it is too difficult to understand. Welcome to the world of chaos theory. You *did* skim that subject as it came up in paleontology and climactic conditions, didn't you? And the best answer for what will happen due to increased carbon dioxide emissions from the burning of fossil fuels is....?

The answer is: Unknown, but minor.

Now, mind you, we live in a meta-stable world for climactic conditions, so minor changes can have a large influence in the short run. But (and it is a big BUT) taken as a whole, the very worst that can happen is a minor extinction event, like those seen after the big K-T extinction. And *that* is the worst we can do.

Except, of course, we are one species. And for each extinction event each species will take a weighted set of dice and throw them. They don't know how the dice are weighted. They don't know what the magic number of species survival is for their species. They just roll them and see what the results are. At the very, very worst we are taking a gamble on the order of a minor asteroid impact.

Much, much, much more worrying is a caldera event in Yellowstone National Park. That sucker will be huge.

And it is overdue.

And the ground is moving there... slowly...

Carbon dioxide? Not a big worry.

See that big dip at 600,000 [amended, much thanks to ABF! 160,000 years ago was a *different* caldera event from Mt. Toba[22 JUN 06] ] years ago? THAT is Yellowstone.[or another caldera maker, there are a few of them 22 JUN 06]

Sleep well!

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