Dinosaurs and the Himalayas

About 30 years ago I heard of the new controversial theory that an asteroid impact caused the extinction of most dinosaurs.  I immediately embraced this as an interesting and plausible possibility.  However, evidence soon appeared that seemed to contradict the theory.  It appears that many dinosaur species existed for some time after the event.  For example, dinosaur fossils were found in sedimentary layers laid down hundreds of thousands or even millions of years after the boundary that marked the event.  (There is a clear line in sedimentary layers all over the world that has much more Iridium precisely marking the impact of the asteroid about 65 million years ago.)

Recently a new possibility occurred to me.  The idea was triggered by a recent question/challenge on QI (one of my favourite TV shows).  The challenge was to put 4 things in chronological order.  Two of the things were a picture of a dinosaur and a picture of Mt Everest.  (I can't remember the other two.)  This got me thinking that maybe the event that wiped out the dinosaurs also created the Himalayas, as I explain below.

But first I go back to the 1980's....

A Bad Idea

After the abovementioned theory was proposed it was quickly disputed but it still seemed likely to me that the events were linked.  The dinosaurs had been around for hundreds of millions of years.  To suddenly disappear within even a few million years of such a huge event seemed to be more than coincidence.

Now when I began this blog (see Intro) I promised to document some ideas that I had when I was younger.  Some were good.  Here is a bad one.

One idea that occurred to me at the time (1980?) was that the asteroid had hit with such force that it had increased the tilt of the Earth.  With greater yearly fluctuations in temperature this advantaged mammals (and birds) which had hair (and feathers) which could be shed during the warmer months.  So, over the next few million years, dinosaurs lost out to species more suited to the new climatic conditions.   Of course, I now know that the asteroid was too small to affect the tilt of the Earth.  (The tilt was caused by a planetoid almost the size of Mars that hit the Earth more than 4,000 million years ago).

Root Cause

The initial event that, I believe, lead to the demise of the dinosaurs, occurred in the asteroid belt over 70 million years ago.  Apparently there was a major collision event that caused a large rock to be placed in an orbit that intersected the Earth's.  It was just a matter of time before it hit the Earth.  Unfortunately (for them) the dinosaurs were oblivious.

Volcanoes

Another proposal for the extinction of the dinosaurs was the massive volcanoes in India at about the same time.  These resulted in huge amounts of basalt being spewed onto the surface of the Earth, resulting in the feature that is now called the Deccan Traps.

What if all these events are related?

Another Idea

My latest idea is that the asteroid that hit the Earth 65 million years ago was not the only one, and not the largest one, to do so at around that time.  Perhaps the earlier collision event in the asteroid belt placed not one but several rocks in an orbit that intersected the Earth's.  Perhaps the largest such asteroid was 50 km across and hit the ocean just south-west of India.  (At the time India was a true sub-continent languishing in the middle of the Indian Ocean.)  There is actually some evidence of an impact crater of the right size in the ocean bed there.  The asteroid was so large as to puncture a large hole in the Earth's crust which caused the massive volcanic activity that created the Deccan Traps.  This in turn propelled India towards Asia with enough momentum to cause the Himalayas to be formed.

So why didn't this 2nd impact cause another sedimentary layer of Iridium?  Probably the asteroid was so large that most of it went through the thin ocean crust and ended up in the mantle.  Also the fact it landed in the ocean meant that there would be less dust thrown up.

So perhaps the dinosaurs were wiped out not by a single event but by two asteroid impacts which occurred hundreds of thousands (or even millions) of years apart.  The repeated blows to the ecosystem, occurring on different sides of the planet, and perhaps also the subsequent volcanic activity, eventually took its toll.  Perhaps there were even more impacts - I believe the first Hawaiian Islands were also formed about 65 million years ago.

This would explain several things:

• Why the Himalayas could be formed by such a small continent hitting Asia.  Nothing remotely similar happened when even larger continents collided, such as Africa and Europe.
  
• Why there are massive volcanoes at Hawaii, which is far from any plate boundaries.
  
• How the asteroid that killed the dinosaurs happened to hit land rather than the much more likely event that it landed in the ocean.
  
• Why fossils of many dinosaurs are found in layers above the Iridium layer (which marks the time of the impact of the asteroid that hit land).
  
• Why so many big Earth events happened around 65 million years ago.

The Earth Is Safer Now

The good news is that if I am right then the Earth is probably safer than we thought!

To cause something as large as the extinction of the dinosaurs might require a 50 km asteroid to hit the Earth.  The largest object that could possibly hit the Earth in the next few hundred years is not much more than 1 km in diameter.  It's possible that something could come from afar (such as from the asteroid belt), but even then we would probably have a long time to spot something that big and do something about it.

Global Warming - Accuracy

A lot has been written about climate change, especially in the last decade or so.  So what can I add to the debate?  Well I have been following the debate for almost 40 years.  I have read many articles and books on the subject in that time and I think I can present the sort of balanced view that I have not seen presented in anything I have yet read.  I consider this to be the most important topic I have discussed since I have probably read and thought about it more than any other.

I will state from the outset that I have always been a keen proponent of minimising human effects on the environment.  I first began worrying about the effects of increases in atmospheric carbon dioxide in the early 1970's, when I read about predictions that sea-levels could rise up to 10 metres by the year 2000.  Since then I have (with good reason don't you think) become a little more sceptical.  However, just because some predictions have failed to eventuate does not mean that we can ignore them all forever more; after all the boy who cried wolf was proven right in the end.

I also come from a scientific background and have the utmost respect for scientists.  However, scientists are human, and are subject to the foibles that we all have.  History has shown that accepted science is not always correct and that scientists are often not as rational and unbiassed as they would have us believe.

This is a fairly large topic so I have split it according to my four A's, that is:

accuracy - how accurate are the measurements and predictions
avoidance - assuming the predictions are accurate how easily can we avoid the consequences
adaptation - assuming we can't avoid some or all of consequences how can we adapt
acceptance - finally how can we accept what we can't avoid or adapt to

Accuracy

There are two aspects to accuracy.  First, there are reports that the effects of global warming have already been measured, such as rising global temperatures.  Second, there is the accuracy of the predictions to consider.

Temperatures

It is commonly stated that global temperatures have risen by about one degrees Celsius since the start of the industrial revolution based on millions of readings mainly from weather stations.  Any one of these readings could easily be inaccurate for any number of reasons but the hope is that the inaccuracies will average out.  However, there are systematic errors that could mean that the perceived trend of rising temperatures is not real.

One problem is that the thermometers that were used till the middle of the last century tended to give higher readings as they aged.  I believe this means that global temperatures were perceived to have risen until about 1950 after which they were perceived to have fallen for a while, when in fact no such changes took place.

Another problem that I think would have a larger, though difficult to quantify, effect is human activity on local climate.  Most weather stations are *not* located in isolated locations.  I believe human activity in the immediate vicinity of many weather stations means that local temperatures would rise over time.  However, this does not mean temperatures in remote locations have risen or even that global temperatures have risen very much.

For example, in the country town where I went to high school the weather station was located at the airport which was far from the town.  Since then the land around the airport has been cleared (eg for a golf course), there is probably more air traffic at the airport, and there is also a new taxi-way not far from the weather station.  All these factors mean that the air temperature is warmer in the immediate area.

Glacier Retreat

Most of the worlds glaciers are currently retreating.  However, this is mainly due to the fact that the glaciers built up during the "mini ice age" about 200 years ago.

The mini ice age is generally not considered to be caused by any sort of human activity.  I believe it was due to increased volcanic activity at the time.

Due to time-lags most glaciers are still retreating to their natural size for the current global temperature.

There is some evidence that glacier retreat has accelerated in the last few decades.

Sea Level

Rises in the level of the oceans will be the biggest repercussion of global warming.  It is due to reduction in the size of glaciers (see above) and to thermal expansion of water.  Some studies seem to indicate that man-made global warming is causing a rise in sea-levels.

Personally, I think it is very difficult to accurately measure changes in the sea-level except by satellite, since you don't know if your reference point is itself moving.

It is generally accepted that sea-levels have been rising by about 1 mm per year for hundreds of years but this is not due to human-induced global warming.  The best studies indicate that there is little or no acceleration in this trend.

Climate Models

Most predictions of the effect of increased carbon dioxide in the atmosphere are based on very sophisticated computer models.  I believe these models are getting better as computer processing power increases and climatologists begin to understand all the factors involved.  (Certainly weather forecasts are far more accurate than they were 40 years ago.)

I think these models have several problems which I will discuss shortly, but first I will try to give you an idea of how difficult it is to model such complex and chaotic systems.  I believe that the world's climate is at least as complex as the world economy.  Despite all the money spent on climate modeling a lot more is spent on modelling the world economy, given all the cost/benefit involved.  Despite this these models fail to predict risks, as the recent GFC has demonstrated.

There are such a huge number of variables to consider in climate modelling and they involve so many different areas of science (biology, physics, chemistry, geology, etc) it seems likely that there are huge gaps.  Further, it is hard to estimate the exact size of feedback loops, time-lags etc.  Due to the chaotic nature of the systems small variations in one factor can have large an unexpected effects elsewhere.

Another problems is that these models are based on data (such as the global temperatures we saw above) that may be inaccurate.

The main problem I have with these models is that they are not subject to the scientific method - ie make a prediction, test the prediction, then abandon the theory if the prediction is wrong (or else continue making and testing more predictions).  With climate models if a prediction is proved incorrect then it's usually just a matter of tweaking a few variables until the model fits the facts again.  In the best case if a prediction is incorrect then the "scientists" try to find some new factor(s) to explain the results, and then these factors are incorporated into the model until once again the model matches the data.

Never does anyone attempt to disprove the fundamental assumptions on which the model is based.  Scientists should be trying to disprove their theory, not continually changing it to make it work.

Worse still, is that the model may be able to be tweaked in different ways to obtain the same result.  The temptation would be to make adjustments that are more likely to gain more funding or have your latest academic paper pass peer review for publication in the Prestigious Climatologist Journal (not a real publication AFAIK).

Prediction Bias

This brings us to the discussion of whether climatologists tend to exagerate the effects of human-induced climate change.  Unfortunately, recent leaked emails seem to indicate that many have a tendency to distort the facts.  Whether this is purely for personal gain, or with the best of intentions is unclear, but the fact remains that a true scientist always seeks the truth despite personal beliefs or desires.

Their defence is that they are only trying to counter the disinformation being put out there by "skeptics".  While it is true that there is a lot of unscientific nonsense being espoused by all sorts of idiots, I believe this occurs on both sides of the debate and the actual scientists should not get involved in such stupidity.