Next post: Global Warming -- The Truth and The Myth

February 28, 2010

Global Warming -- The Truth and The Myth - 2

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The history of climate temperature trends

History is greatest source of knowledge. After all history is nothing but an accumulated knowledge of innumerable minds, events. To have a better future we must learn history. We observe, analyze, learn, correct and better ourselves which leads to evolution. But what if history itself is a puzzle? What if the hands which pass on the history to new generations mishandle it? For better or worse - how to trust?

The question arose and man baffled. He is common man, like me. 

Ask a psychologist on why a person is behaving as he is and he will explain it to you. Ask him to observe and link the behavior of all family members of that particular person and that will be a challenge for psychologist. Then ask him to link the behavior of all the citizens in that city, state or country. And then to interconnect behavioral nature of human being in whole globe! The probability of making a mistake increases in each stage. Why does it happen? When you need to interlink two data you need to find some relation between the two. In simple terms you need a formula that should hold good for all and satisfy all conditions. To find it is real tough task ahead. Something similar happened with global warming. There were theories to explain warming of the climate. Now people wanted to connect them because they strongly felt or their theory pointed to an overall increase in average temperature on Earth. The real challenge was to study the pattern of changes in average temperature over the past and the present. This could demonstrate us how temperature varied all the while in the past, how it is changing[increasing] in recent years rapidly and if it continues this way how would our future look like?

But it is not as simple as it looks. There are many challenges involved in this. First, collect the historical data of temperature on Earth. It requires an answer to, from what all locations we should pick temperature data which could give a meaning to what we say ‘Global’. Next, need to find the mean temperature with all collected information. Also you need to determine on differentiating the data based on factors such as ocean, land, which layer of the atmosphere, etc. The factors in a particular location which could have been exposed to some sudden climate changes due to natural/manmade pollution also need to be taken care of owing to the impact it might have on the mean value of the data.

As I have mentioned earlier there was no temperature data available until recently. A team of scientists used paleo-climatic data from about 17 sites around the world to generate a thousand year long records for both northern and southern hemispheres. This used multi proxies of temperature sources such as tree rings, ice core. Jones et al. came up with a report which affirmed 20th century is the warmest of last 600 years. 

But later it received high criticism over the methodology used in constructing temperature trends and to correct the UHI effects [UHI refers to the tendency for urban areas to have warmer air temperatures than the surrounding rural landscape, due to the low albedo of streets]. Different individuals reported their studies indicating, in regions as in Australia, northern or southern hemisphere the stations that are considered for the study by Jones et al 1986 were affected with UHI. Considering Australia, Jones et al 1986 looked at 86 Australian stations and rejected 46 (25 Short term – 21 long term). Of the 40 they used 27 were short term and 13 long term. Of the long term there were 5 large cities. There are claims that Jones et al systematically truncated data and ignored more rural data.

Even the Peterson 2003 report which claimed there is no observable difference in urban and rural trends in its network has been criticized by many. If we consider both rural and urban trends there is a difference of about 0.7 0C. And when you consider cities with major league sports franchise along with rural you will find over 2 0C per century!!

Moving little back in time, IPCC 2001 report came up with a terrifying graph:

This is famously known as ‘Hocky Stick Graph’ with its look-alike pattern. The debate concerning the methodology started in 2003 with Stephen McIntyre, the editor of Climate Audit, and Professor Ross McKitrick, a Canadian economist, raising voices against Mann et al.’s [Michael E. Mann, Raymond S. Bradley and Malcolm K. Hughes] hocky stick graph claiming that the graph has serious flaw/defects in its data and calculations. This led to two important investigations. One by scientists convened by NRC [National Research Council] and other one by three statistician chaired by Edward Wegman, statistics professor who was also past chair of the National Research Council’s Committee on Applied and Theoretical Statistics.

Interestingly the outcomes of two investigations differed. NRC report supported MBH [Mann et al.] reconstructed temperature graph and mentioned that though there are shortcomings in the statistics they are small in effect. And the Wegman report [committee on energy and commerce report] mentioned that MBH98 and MBH99 were found to be "somewhat obscure and incomplete" and the criticisms by McIntyre and McKitrick were found to be "valid and compelling." Both listed the reasons of their findings.

Also Mann did not wish to make the data/source code used in their study public. But finally he had to make the data public after a lot of criticism and pressure. Once it was available reviews are done and in 2005 McIntyre and McKitrick mentioned that 7 of their 10 findings are confirmed by reviews. But again in 2008 Mann et al. published updated reconstruction of Earth’s surface temperature and again McIntyre and McKitrick reported new studies with criticisms.

If that is one story few skeptics also came up with below interesting graph:

It is crystal clear from this graph that there is dramatic increase in average temperature starting 1990. But the point to note is there is dramatic decrease in number of stations starting 1990!! Is this merely a coincidence? Is the loss in number of stations uniform across the world? From the data it was found that this loss in stations occurred mostly in former Soviet Union, China, Africa and South America. Now, that is called cherry-picking the data to prove that global warming is happening and very fast.

In recent time, especially after climategate incident the temperature data reliability has become most suspicious. At the end of 2009 New Zealand Government’s chief climate advisory unit NIWA is put under fire for manipulating raw climate data to depict a strong global warming trend which did not exist. And similarly it happened in Russia as well. IEA [Institute of economic analysis] issued a report which claimed Hadley center for climate change based at British Meteorological Office headquarters had probably tampered the Russian-climate data. It is said that while Russian meteorological stations cover most of the country’s territory, the Hadley Center had used data submitted by only 25% of such stations in its reports. And the data of stations that are not listed does not show any substantial warming in late 20th century.

To understand this cherry-picking is not really difficult. Consider below:
The temperature patterns in both look different. If I want to support global warming I use only Bangalore’s data skipping Cochin’s. While this is just a very raw example to show what can be done to prove global warming.

And coming to very recent time, while I am certain most of us felt January 2010 is mostly found to be the coldest one. But surprisingly it is found that, considering sea surface temperature January 2010 is second warmest in last 130 years. But at the same time land temperature is not that significant [12th warmest]. And coming to sea surface temperature it is attributed to El Nino conditions in the pacific.

Now the question is - With all this information what do we understand? The only answer I can give is, the history of temperature trend itself is still a big question.

We need to check few things before we move further or else this discussion becomes incomplete.

Truth always emerges out of a contradiction. Contradiction raises questions. And the truth that contradiction cannot exist starts a quest for a higher truth which will clear the contradiction. In this way, contradictions play a very important role in growth of science and hence the society. But on the other side, there are forces that create contradictions to mislead us from the path of truth. What is the motive behind these forces - is a different question.

So where does the questions, concerns or claims of the skeptics stand? Are they to mislead us? Are they delaying the steps that need to be taken to avoid a global disaster?

Existence of Global warming is not a claim or an idea with little importance. You started with an idea that global average temperature is raising. And you wanted to prove it. Now, to prove it you must prove that it exists. In order to do that you need to compare temperature data over many thousands of years and not mere few tens/hundreds of years. But the fact is we don’t have such data available. When we tried to get the data generated using proxies they are being questioned for which there no satisfactory answer is given.

Even when it seems that most agree to the point that in recent years temperature definitely increased there are certainly great differences in the views over many questions such as ‘what is average increase in temperature?’ or ‘as global warming supporters really claim, is it mainly due to greenhouse effect?’

But for this complexity of the situation do we see any solution? Is there a way to achieve consensus over a methodology to clear our views over the temperatures trends in the past? One probable solution I can see is to go public. Make the information, every source code public. Don’t make any adjustments to the raw data. Let all men of related section debate over the approach. I am certain we will find a more correct and efficient approach. No one can hide any truth; mishandle any data without letting know others. Don’t you think then people will have more satisfaction over the way things are moving. If you want to put up a theory let others observe, analyze and scrutinize it so that the validity of your theory is established. In this process your theory might undergo few changes for the better and correct itself. Don’t you think this will avoid any chances of creating a contradiction with an intention to mislead people?

And finally, don’t you think this is possible? It just requires an open debate with a chance for everyone to review the data. While there might be concerns over financial terms like funding for the research which force the scientists in corresponding research field to withhold information they have. But yes, if it continues that way I really don’t see any other way to establish the truth in simple way; not at least in the short period we expect. It might really take tens of years just to clarify all questions relating to history of temperature trend. The truth has to emerge one day. But with the approach we have right now it is going to take more time.

In order to move further to other topics let’s consider the point that global warming is happening and leave aside the question ‘At what rate?’ Further sections will deal with questions such as, ‘Is it something we need to really worry about? Is it natural or man-made? What are policies brought up to curb global warming? What should we do to avoid any possible disaster? ...’

Next post on the factors contributing to global warming...

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Madhan said...

I always thought Global warming was a phenomenon POST industrial revolution. Why do we need data for thousands of years, shouldn't we take any action even if GW is natural, shouldn't we look at the options of slowing it ? If we extrapolate current rate, the result will devastating isn't it ?

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Daniel Milstein said...

That is true,Manoj. As an author and business man, I can relate to how you said, "Even the Peterson 2003 report which claimed there is no observable difference in urban and rural trends in its network has been criticized by many". I hope more people discover your blog because you really know what you're talking about. Can't wait to read more from you!

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