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Science communication is important in today's technologically advanced society. A good part of the adult community is not science saavy and lacks the background to make sense of rapidly changing technology. My blog attempts to help by publishing articles of general interest in an easy to read and understand format without using mathematics. I also give free lectures in community events - you can arrange these by writing to me.

Friday, 17 August 2012

Announcing Population Growth and Sustainability Talks in September 2012...

In partnership with Glasgow University and Scottish Enterprise, Lanarkshire, and following the initial announcement of the planned talks
I can confirm that I have arranged

four talks lasting 90 minutes each on
Saturdays 8, 15, 22 and 29 September 2012. 
Talks start at 11 am and end at 12:30 pm. The venue is
James Watt Auditorium, E.K. Technology Park, G75 0QD
with ample free parking on site. 

The talks are free to attend and require no science background. 
The talks are particularly suitable for school pupils and general community. 
Everybody is invited to the discussion of this highly relevant subject -
Talks promise to be informative, exciting, somewhat controversial and I am sure will be followed by thought-provoking exchanges.

The contents of the talks are:

Talk 1:  Population: Exponential Growth and Ecosystem Response
Talk 2:  Managing Climate Change:  Oceans and Atmosphere
Talk 3:  Managing Food and Water Resources
Talk 4:  Managing Energy Resources 

For further information and if you wish to express interest in attending the talks then write to 
Come along to the talks and support the popular community education initiative. 
Inform your family, friends, neighbours about the talks - it is your programme.

Thursday, 16 August 2012

Explaining Exponential Growth - its basic features...

One can find examples of Exponential Growth (EG^) in almost all fields of life.  EG^ mathematically describes how some fundamental attribute of a system will change with time.  Systems with EG^ can show non-intutive bizarre behaviours and makes exponential growth a difficult concept to comprehend and accept its conclusions.  
Mysterious as it may sound, an understanding of EG^ is crucial to appreciate what is going on in our daily lives and to plan for the future.

From calculating the interest earned on your capital to using Moore's Law to predict the number of transistors on a chip, or to calculate the power output in a nuclear reactor, EG^ is there to help. Its twin brother, exponential decay (ED^) only differs in the direction of change but shares all the concepts of EG^.

There are three ways to describe EG^ - they are equivalent but one is used in preference to others depending on the situation:  In EG^

1. Rate of change (% Change) depends on the amount present. e.g. 
Annual interest rate is 5% (interest earned per year is 0.05 times the money at the start of the year). 
Inflation index which measures the % change in the cost of a basket of goods over a year, was 2.5%. 
Global population increased by 1.4% per year in the 20th Century.
E.Coli colony increases is size at 3.5% per minute.  etc...

2.  The quantity present doubles after a certain time.
(Doubling Time) 
If you leave your money in a bond, it will double in 14 years
Inflation will double the cost of goods in 28 years.
Global population doubled every 50 years in the 20th Century.  
E Coli colony doubles in size in 20 minutes.  etc...

3.  Doubling steps: 
Accumulate something with the added amount doubling in successive steps.

The only important parameter in exponential growth is
% rate of change or doubling time. 
Rate of change and doubling time are measured in the same units of time - be it years, minutes, seconds, centuries, nanoseconds or whatever. 
They are simply related as follows (called the rule of 70):

% rate of change = 70 divided by the doubling time, and of course
The doubling time = 70 divided by the % rate of change

If we start with 1 unit and the doubling time is T then at time

10T the number of units will be 1,000 (actually 1024)
11T                                          2,000
20T                                              1,000,000
30T                                              1,000,000,000
40T                                                 1,000,000,000,000 
41T                                                 2,000,000,000,000
What quantity (population, money, no of transistors) and  the unit of time (years, seconds, minutes etc.) you choose  depends on the problem.

The thing to note is that at 10T after one doubling time, the growth was 1,000;
while at 40T after one doubling time, the increase was 1,000,000,000,000 - a billion times greater. 
This is true of all systems showing exponential growth - this is simple maths.

Also note that in each doubling time, the increase is as much as has happened in all the previous doubling steps. 
So when we say that energy consumption will double in 40 years; it means that in the next 40 years we shall consume as much energy as we have used since the beginning!  To make it clearer:
From 1970 to 2010 we used as much energy as we had used from 1800 to 1970.  (1800 is used as a reference point - energy used before 1800 was very small)

If we were to plot the quantity against time then the graph will show very little change in the beginning but after 10 or 20 doubling times the numbers would have grown to thousands of times bigger and the graph will show an almost vertical swing.

Another interesting property of EG^ graph is that it looks the same no matter what section of the graph you are looking at.  For example, in the picture, you can change the x-axis (time axis - doubling steps) from the current range of 0 to 14 to a range from 20 to 34.  The y-axis (quantity) will be changed to start at 1000,000 (the actual value at 20 doubling times) and go to 4,000,000,000 (at a doubling time of 34).  The curve on the graph will be exactly the same. 
Isn't that wonderful?

Here is a chart of how world population grew in the past 

Wednesday, 15 August 2012

Human Population Dynamics on a Finite Earth....

Growing human population with its habit of over consumption on a planet with finite space and resources provides some fascinating scenarios.   Population quadrupled in the 20th century.  The momentum of population growth will almost certainly take us from 7 billion in 2011 to over 9 billion by 2050. 
Where do we go from there?  the situation is serious enough that I shall deliberately make some provocative statements to start a serious debate.  We need to look at the big picture and come out of the habit of theoretically solving a local limited problem and announce that as a solution to everything.

In examples  1 and 2  we set out the nature of exponential growth.  Example 2 is directly applicable to human population on earth for which the doubling period is not one week (as it was in example 2) but somewhat longer - 50 years in the 20th century and may be of the order 100 years in the 21st century.  The increase in doubling period might partly be a result of humans hitting the earth's resource ceiling although many experts think that we reproduce less as we grow richer and doubling in numbers takes longer.  Some even feel that if we all got much richer then population will start decreasing.  Let me explain the problem with this line of thinking:

On average, about a quarter of us are living very well - are rich.  One third of us (China and India with a combined population of 2.5 billion) would like to increase consumption seriously to reach at least the European levels.  The remainder live at or below subsistence levels.  Currently we use resources in excess (1.5 times) of what is considered sustainable.  To raise every body's standard of living to European level will require resources of 4 Earths; to reach US levels will require 15 Earths.  And we are talking about 7 billion population.  Consumption by 9 billion rich humans will be correspondingly greater.

Look at it another way:  To support US style living for everybody on earth, we need to reduce our numbers by a factor of 15 - the population can only be about 500 million.  The reproduction rate will be no problem according to experts when we are all rich but how do we reduce the population to 500 million.  Please send me an e-mail (ektalks@yahoo.co.uk) if you think I have missed something here.
The conclusion I draw is that we have already hit the resource ceiling and increase/decrease in human population will now be governed by the resource limits of our ecosystem. 
It is not possible for our visionary world leaders to make the 7 billions of us rich quickly.

Some say that science and technology will solve the resource problems.  NanoTechnology (NT) will produce limitless food without waste, will be nonpolluting, even clean up past pollution, etc. etc...  
NT will also improve medical care, may be even allow people to live for ever (much longer than 100 years would not be unreasonable); thus decreasing the death rate drastically.  Population growth is the difference of birth rate minus the death rate.  For stable population birth rate must be zero if nobody dies.  Imagine a world full of 100 year old rich people.  Who will do the work?  Robots probably?  But then will these robots no get fed up with humans and decide to do something about it - after all they will think logically!  Now this is the subject of my blogs in 2013. 
Let us go back to human population scenarios:

The reason I think zero or negative population growth is not possible is the way exponential growth works.  This was explained in example 2.  We looked at doubling steps.  Even if 99% of the population dies the remaining 1% will grow back to original numbers within 7 doubling steps - 350 years in the case of humans.  What this means is that if a natural or human generated catastrophe eliminates 99% of the population - it will be 7 billion again in 350 years.

Nations of the world do not all think the same way.  Population, largely poor, in African and South American (A&SA) countries is doubling in 25 years or less.  Rest of the world might stabilise its population but in 100 years, A&SA will have increased their population by a factor of 16.  India's population is projected to reach 1.6 billion in 2050 from 1,2 billion now.   Indigenous US population is not expected to grow but to do the work they will allow 100 million new immigrants over the next 40 years who will demand US style standard of living.  Effectively US population will grow by more than 25% over the next 40 yaers. European population trends will not be much different from US - I believe.  It seems clear to me that eventhough local population in rich countries does not grow by itself, new immigrants will boost the population - and the arguments about reproduction rates decreasing with prosperity do not hold out - unfortunately.

So where do we go from here - if global population continues to incrase with a doubling period of 100 years then in 1000 years (10 doubling periods) the population will hit a number of 7000 billions.
what it means in terms of space and resources is quite obvious.  As I had said previously - it won't happen.


Tuesday, 14 August 2012

Population and Exponential growth ... (part 2)

Exponential Growth produces some surprising results. 
The next example has been discussed in different forms - I prefer my version.

A clump of alien life (A.L) falls on Earth in the middle of an abandoned wall garden somewhere in Italy. 
It can grow by using energy from the Sun and gases from the atmosphere - doubling in size every week.  It is bright orange in colour so easy to see, and spreads in a single layer to maximise energy capture. And, 
It can be killed by spraying coke.  

Let us assume that by the end of 40th weeks, A.L had covered 1/16th  or 6.25% of the surface area in the walled garden  
By the end of 41st week, the area covered has increased to 1/8 - 12.5%
By the end of 42nd week, the area covered has increased to 1/4 - 25%
By the end of 43rd week, the area covered has increased to 1/2 - 50%
By the end of 44th week, A.L fills the whole area in the walled garden!

Notice that it took A.L 40 weeks to occupy the first 6.25% of the garden (and during the first 40 weeks of observation, the garden would have looked relatively free from alien life) but in the next 4 weeks A.L occupied the remaining 93.75% leaving no free space.

In 4 weeks, the unoccupied area reduced from 93.75% to 0%
In the last week, A.L added as much area as it had done since the start.

Getting worried by the spread of alien life, coke was sprayed killing 99% of A.L
1% of A.L, that survived, grew as before doubling every week and in just over 6 weeks it had covered the whole area again.

Cloudy weather would prevent Sun reaching A.L and reduce its growth rate to say half - A.L doubling every two weeks. Then A.L will take 88 weeks to cover the garden.  The growth rate could vary from one week to the next and an average rate will prevail.  Different parts of the garden could grow at different rates but again an average rate will determine how long it takes A.L to cover the garden.

Extinctions, variable rates, geographically different rates etc. only affect the time it takes to cover the garden - end result is the same. 
What matters is the number of doubling periods.

Remember 1 grows to 1000 (actually 1024) after 10 doubling periods
1 grows to 1,000,000,000 after 30 doubling periods
1 grows to 1,000,000,000,000,000 after 50 doubling periods; that is 1000 trillion.
Rule of thumb is that numbers increase by 1000 after 10 doubling periods.

Exponentials, % Growth Rate, Doubling Time...

The dynamics of money supply, debt, inflation, population, energy use, digital electronics, green house gas concentrations, bacterial colony growth, radioactivity and many many other phenomena show exponential behaviour.

The science is so simple to comrehend but the consequences can be totally counterintutive, fascinating, baffling and many a times frightening.
And it always starts with a nice slow pace gaining momentum as it goes along and before you know it, it has become a monster.

Let us start with a couple of fun examples; I use them as party games:

1.  Take a big sheet of paper - normal paper is 0.1 mm thick.
      Fold it 1 times - the thickness of folded paper will be 0.2 mm.
      Fold it again - the thickness is now 0.4 mm.
      Fold is again - the thickness is now 0.8 mm.
     continue this folding for a total of 50 steps
     What do you think the thickness of the folded paper will be??

   The height of the folded paper will be more than 100,000 km!

2.   A chess board has 64 squares.  Place
      1 grain of rice on the first square,  (Total grains = 1)
      2 grains of rice on the second square, (Total grains = 3)
      4 grains of rice on the third sqaure, (Total grains = 7)
      8 grains of rice on the 4th square,   (Total grains = 15) 
      16 grains of rice on the 5th square and so on...

      Continue doubling the number of grains on the next square  
      Fill up to the 64th square on the board.
      How much rice will you need to fill up the board?
      You will need 400 billion tonnes of rice to fill up the board!
       This is about 1000 times annual global rice production. 

UNBELIEVABLE - Of course one hits reality limits before you can finish.  You cannot fold a piece of paper so many times and there is not enough rice to fill the whole board. 
These are examples of Exponential Growth.

There are a few important observations one makes here:

1.  Size of each step is double the size of the previous step
2.  Amount added in a step is greater than the total amount added in all the previous steps by one unit 

Let us now consider an example where time is involved:
Look at the next blog for this ...



Sunday, 12 August 2012

Critical Thresholds in Earth's Ecosystem...

Feedbacks, Tipping Points, Planetary Boundaries, Ecological Footprint, Irreversible Changes, Ecosystem Collapse are mentioned frequently. 
Lot of these are matters of opinion and the time scales associated with such predictions are important.  
When will we reach a tipping point and how long after that the ecosystem will change in a way never to return to the current state are relevant questions.  How long is 'never'?
In planning and making decisions, human time scales range from a decade to a millenium. 
Politicians and policy makers largely work on a timescale determined by the next general election - and that is most unfortunate in the present context.

In relation to the Earth's Ecosystem, Tipping points or Critical Thresholds are real.  They have occurred in the past.  Great extinctions have happened when the world's living species have been reduced to a small fraction of their pre-event numbers.  Even as recently as 12,000 years ago, global temperatures had risen by a massive 5 or 6 degrees in a matter of decades making a transition from the ice age to the warmer interglacial that we enjoy just now.

As human population grows, the rate at which we consume Earth resources and produce waste increases.  Ecosystem services (worth a cool $33 Trillion) have limits.  Earth can produce services we demad and clean up the waste we produce only up to an extent.  We are already using resources of the earth 50% faster than they may be replenished.
There are signs that Earth's capacity is being adversely affected by our overuse and may be weakening.  Increasing consumption will only quicken the weakening setting up a spiral towards collapse.  One can see how a tipping point may be reached if business as usual (increasing population and overconsumption) continues.

Scientists in Journal Nature (2009) have identified nine processes in the ecosystem which have critical thresholds or tipping points (subject to limits or planetary boundaries).  According to the study, three of these processes have already passed the tipping points with the others under serious stress.  Remember, however, it is difficult to identify the actual point when a prcess passes its critical threshold or even to know what the critical threshold is.
National Economic Council Report (January 2010) discusses these processes in deatil.  
At this stage we shall only list them.

1.  Climate Change
2.  Rate of biodiversity loss (terrestrial and marine)
3.  Interference with the nitrogen and phosphorus cycle
4.  Stratospheric ozone dpeletion
5.  Ocean acidification
6.  Global freshwater use
7.  Change of land use
8.  Chemical Pollution
9.  Atmospheric aerosol loading

We shall look at some of these in future blogs.

Saturday, 11 August 2012

Nature Services - a Cool $33 Trillion Worth!

The 1997 study of the value of services that Nature or the Ecosystem provides us was estimated to be worth a minimum of $33,000 billion!  Global GNP was $18,000 billion then. 
The estimates only included renewable ecosystem services, excluding non-renewable fuels & minerals, and the atmosphere.

What are we talking about? 

One way to think about it is to calculate what it would cost to replace the goods and services that nature provides us.  In fact, zero natural capital implies zero human welfare - it is not possible to totally substitute ecosystem services.  Their value is infinite.   

Again, what are we talking about?  Let me give some examples:

Pollination of crops by bees is required for 15-30% of US food production. 

In the drainage basin of Yangtze River, the annual economic benefits of maintaining forests for flood control and power services are estimated to be 3 times than harvesting them once for timber.  China now pays loggers not to cut trees but plant new ones.

Nature provides, we think free of charge, sea food, crops, fresh water, energy (hydro, biomass fuels), climate regulation, waste decomposition, pest and disease control, purification of water and air, nutrient dispersion and cycling... etc.  The list goes on and on.

So, what is the problem?  Why are we talking about it now?

The problem is that most of our decision making does not take into account the effect of our decisions on the health of the ecosystem services.  It seems to have mattered little in the past when the population and pressures on the ecosystem were small, but now the stresses created by humans are such that unless we start to give proper consideration to restoring the health and wellbeing of the ecosystem in our decision making processes then future human welfare may suffer in a big way.

In a proper market, ecosystem services must be valued and paid for.  The price of goods that use ecosystem services directly or indirectly would then be much greater.  For example, the true cost of burning oil, including repair to the environment, is calculated to be about $15 per gallon but in USA they pay $4 per gallon.  Cheap Energy has caused serious damage to the ecosystem.

Some parts of the ecosystem have already passed critical thresholds or tipping points and others may do so in future.  This will impact adversely on human welfare - already it is reckoned that since 1970, even though global GNP has gone up, human welfare index has not.

We shall look at the ecosystem stresses annd what we can do about it in the next blog.

Friday, 10 August 2012

Stability, Feedback and Tipping Points - (Part 3)

These days, Tipping Point is frequently used in discussions to describe a point of no return or a point of sudden and large change.
The change may be undesirable, catastrophic, unpleasant, unplanned, unexpected or irreversible.
Alternately the change may be sought for, as in marketing a product, or in social media to generate a lot of contacts. 

Stable systems return to their normal state of stability after they are  disturbed slightly by an external agent;  Remember the example of a marble in a bowl  Negative Feedback

However, if the marble is pushed more and more until it reaches the top of the bowl,  then a slight further push will take it to a new state from where it can not return to the original state.
The marble has passed the tipping point.  Beyond the tipping point, there may be a new state of stability, as shown in the diagram, or there may be a precipice, cliff edge – a point implying catastrophe.

Small changes can build up to bring a system to a state (tipping point) that even a further small change can cause large and irreversible shift in the state of the system. 

The pressures that human activities are placing on the Earth's ecosystem are increasing and we may be reaching a tipping point when serious undesirable and damaging changes to the ecosystem become inevitable. 
Earth is rapidly approaching a tipping point
Ecosystem collapse?

When the tipping point happens is difficult to predict.  In a complex system with many parameters it is not possible to exactly say when the system will switch to a new stable state or collapse.  One looks for signs of stress and forms an opinion about the future behaviour of the system.

A good read is Malcolm Gladwell's book in which he describes The Tipping Point as that magic moment when an idea, trend, or social behaviour crosses a threshold, tips, and spreads like wildfire. Just as a single sick person can start an epidemic of the flu, so too can a small but precisely targeted push cause a fashion trend, the popularity of a new product, or a drop in the crime rate.  He describes several examples such as a New Yorker district which becomes more and more dangerous because of small changes such as broken windows which convey the message to people that the neighborhood became less caring.

Wednesday, 1 August 2012

Stability, Feedback and Tipping Points - (Part 2)

In positive feedback, a change in one parameter causes other changes which then amplify the magnitude of the original change.

Example:  Arctic Ice Loss.  Global temperatures have risen but temperatures in the Arctic have increased much more rapidly over the past century.  This has resulted in melting of the ice cover in the Arctic circle.

Change (increase) in the one of the climate parameters (temperature) has caused change of a second parameter ( area covered by ice in the Arctic).

Ice is highly reflective.  Fresh snow sends back about 80% of Sun's energy falling on it, while ice is ~50% reflective. 
Melting converts the ice to darker water that reflects less than 10 percent of solar energy and absorbs the rest.
Greater absorption of solar energy increases the temperature which then causes more ice to melt...
A positive feedback cycle operates...

Another example of positive feedback is thawing of the permafrost - frozen earth in Siberia, Alaska and Canada. 

Positive feedback causes a drift away from the original stable situation. 
The drift may continue and become uncontrollable. 
Alernately, due to changes happening, other internal mechanisms of the system may come in and pull it back towards stability.
If the drift due to positive feedback continues then we can reach a tipping point - we shall discuss this in Part 3

World's Wittiest Best Quotes...

It is amazing how some people can say so much in a few words...

We are living in a world today where lemonade is made from artificial flavours and furniture polish is made from real lemons          ALFRED E. NEWMAN

People are more violently opposed to fur than leather because it's safer to harass rich women than motorcycle gang               JOHN VARLE
We have two ears and one mouth, so that we can listen twice as much as we  speak                 EPICTETUS (c 55-135 AD)
A celebrity is a person who works hard all his life to become known, then wears dark glasses to avoid being recognised                        FRED ALLEN
"We live longer,  but we think shorter.”       MARY CATHERINE BATESON
If you wanted to make an apple pie from scratch, you first had to create the universe              CARL SAGAN
No diet will remove all the fat from your body because the brain is entirely fat. Without a brain, you might look good, but all you could do is run for public office                       GEORGE BERNARD SHAW
Interesting people are nonconformists, swimming tirelessly against the flow of the cultural norm. Only dead fish go with the current.          ROY WILLIAMS
One camel does not make fun of another camel's hump.                   GHANAIAN PROVERB
If things are clear then they will have sharp edges  ANONYMOUS 
My grandfather once told me that there are two kinds of people: Those who do the work and those who take the credit.  He told me to try to be in the first group; there was less competition there.          INDIRA GANDHI
A lot of the people who keep a gun at home for safety are the same ones who refuse to wear a seat belt.                 GEORGE CARLIN
If dandelions were hard to grow, they would be most welcome on any lawn.        ANDREW MASON
How is it that we remember the least triviality that happens to us, and yet not remember how often we have recounted it to the same person.                         DUC DE LA ROCHEFOUCAULD
Why inflict pain on oneself, when so many others are ready to save us the trouble?                GEORGE PACAUD (1879-1937)
Ever notice that 'what the hell' is always the right decision?                 MARILYN MONROE (1926-62)
Quality is never an accident; it is always the result of intelligent effort.          JOHN RUSKIN (1819-1900)
The greatest pleasure I know is to do a good action by stealth, and to have it found out by accident.  
 CHARLES LAMB (1775-1834)
The average man, who does not know what to do with his life, wants another one that will last forever.                               ANATOLE FRANCE (1844-1924)
Often when I pray, I wonder if I am not posting letters to a non-existent address.          CS LEWIS (1898-1963)
Like airplanes, we all leave behind a vapour trail. And though we can easily see others’, we rarely see our own.     RP SIEGEL
If you think you are too small to make a difference, try sleeping in a closed room with a mosquito.             AFRICAN PROVERB
Some cause happiness wherever they go; others, whenever they go.
Everything we hear is an opinion, not a fact.  Everything we see is a perspective, not the truth.   MARCUS AURELIUS (121-180 AD)
The best way to predict the future is to invent it         ALAN KAY
One who is proud of ancestry is like a turnip; there is nothing good of him but that which is underground.   
AMUEL BUTLER (1835-1902)
If you have an apple and I have an apple and we exchange these apples then you and I will still each have one apple. But if you have an idea and I have an idea and we exchange these ideas, then each of us will have two ideas.      GEORGE BERNARD SHAW (1856-1950)
"Because almost everything -- all external expectations, all pride, all fear of embarrassment or failure -- these things just fall away in the face of death, leaving only what is truly important." "Remembering that you are going to die is the best way I know to avoid the trap of thinking you have something to lose. You are already naked. There is no reason not to follow your heart."                 STEVE JOBS (1955-2011)
We are here on Earth to do good to others. What the others are here for, I don't know.        WH AUDEN (1907-73)
Ideas are more powerful than guns. We would not let our enemies have guns, why should we let them have ideas?                   JOSEPH STALIN (1879-1953)
Don't be afraid to go out on a limb. That's where the fruit is.            H JACKSON BROWNE
They say such nice things about people at their funerals that it makes me sad that I'm going to miss mine by just a few days. GARRISON KEILLOR
“Forget Jesus, the stars died so you could be born.” LAWRENCE KRAUSS
“There are thousands and thousands of people out there leading lives of quiet, screaming desperation, where they work long, hard hours at jobs they hate to enable them to buy things they don’t need to impress people they don’t like.” — NIGEL MARSH

All truth passes through three stages.
First, it is ridiculed.
Second, it is violently opposed.
Third, it is accepted as being self-evident                             ARTHUR SCHOPENHAUER

  • Whenever a friend succeeds, a little something in me dies.
  • Never have children, only grandchildren.
  • A good deed never goes unpunished.
  • It's not enough to succeed. Others must fail                                                                                GORE VIDAL(1926 -2012)