Ant, my son, writes to me from time to time from his hometown in Philadelphia, USA and the following is part of his recent letter.
I value his views, particularly as a Senior Scientist and pleased of his reasoning on this issue having held simular views for many years, mind you I haven't done the research he has.
I've spent some time reading up on what is going on with global warming after the release of emails and documents from the CRU at the University of East Anglia. Previously I was inclined to give the experts, a la Al Gore, the benefit of the doubt and accept the global warming conclusion without doing much research of my own.
Regardless of global warming (or cooling) I still think it is prudent, and just plain common sense, to look after our environment and minimize our impact. So energy efficiency, reducing pollution, reducing the burning of fossil fuels, preservation of forests and natural habitats, are all aims I support and think governments and companies should be doing more to support.
What I've found from digging into global warming is that it isn't true.
When I look at broader data sets and raw data, without fudging selected data and omitting other data, you find there is no warming trend, and most likely there has been a cooling trend over the past 5-10 years. Another thing too is that our life on earth depends upon a greenhouse effect of about +33°C, without which the global average temperature would be -18°C instead of the +16°C it currently is.
Historically CO2 levels are lower now than they have been for millions of years, and the temperature is also less than it has been for most of the past 600 million years (apart from a few brief cold spots). Over the past 600 million years the global average temperature has fluctuated between 10 and 25°C.
The average temperature over the past 600 million years has been around +18°C, and the average CO2 concentration has been about 8x what it currently is. Temperature has fallen steadily from around +22°C to its present value over the past 50 million years, and CO2 has fallen steadily from 8x to its current level over the past 150 million years. There is a case for expecting the CO2 and temperature to be higher and closer to the norm.
The second problem I've found is that the hypothesis that increased CO2 causes increased temperature is also almost certainly not true, and is definitely not true in the simplistic way that it is presented in the media. When CO2 and temperature data are compared it is clear that CO2 increases have historically occurred with a lag of at least 5-10 years following temperature increases.
In a simple system (like a closed box) you can calculate that an increase in CO2 will result in an increase in absorbed radiation and consequently an increase in temperature; and I agree with these calculations. But the problem is that in a real world case the calculations are too complex and can't be solved (at least not with current knowledge and not without many assumptions and fudge factors and simplifications). Since historical data show that CO2 increases happen after temperature increases, you can't conclude that increasing CO2 will cause an increase in temperature. There's more conflicting data, such as tree ring data, tree growth, and temperature being found to correlate with cosmic rays; solar output variability correlating with temperature; the effects of volcanic activity correlating with CO2 and temperature; and recent reports that anthropogenic CO2 is rapidly removed from the atmosphere.
I think what's happened has been collusion between environmentalists and speculators, and politicians have jumped on the bandwagon to further their own ambitions for power and money.
There's trillions to be made trading carbon credits, and there are now new financial instruments (like the infamous credit default swaps) for speculators to gamble with. For a scientist, the goal is to dispassionately record and analyze data. In global warming the stakes are high (doing good or making tons of money, or both), and the problem is so complex that no one really knows how to make a valid model.
I think many of the scientists involved have allowed their ambition (for career, doing good, or profit) to cloud their judgment, much like Shakespeare's Macbeth. Sadly, I think it makes all scientists and science look bad and undermines motivation to reduce emissions, including CO2, reduce waste, and take better care of the environment.
Comments by Ant Van Dyk Ph.D