Dear Eddie:
Thank you for trying to debate your case (and for not joining the clack of Boris and Jeb whose further postings here I shall not answer). We learn from disagreement, but nothing is learned from being disagreeable.
I hope the following adequately addresses your points to me.
You assert that I was “disingenuous” to consider the period since 1998 when the last period of warming stopped, saying to me;
“if you had chosen 1997 or 1999 you could not claim that global warming had “stopped”.”
You ignore my explanation of why consideration of the period since 1998 is very proper. Please read it.
All AGW predictions were for continuous global warming with variable rate: none of the predictions were for a decade of near stasis with slight cooling (as has happened). I was addressing why global Warming stopped in 1998.
It would be cherry-picking to assess the periods from 1997 or 1999 because the start of the present cooling period was 1998. The Earth was still warming in 1997, it peaked in 1998 (an El Nino year) and although its temperature plummeted in 2000 (as the El Nino passed) by 2001 it had recovered to almost reach the high of 1998. The Earth has been cooling since.
And you say;
“Fact is, on a global scale the decade from 1998 has been around 0.8 deg C warmer on average than the first decade of the 20th century. In other words, the long-term trend is upwards”
I address your substantive point and will ignore your exaggerated value of “0.8 deg C warmer”.
I explained that the “long term trend” is recovery from the Little Ice Age (LIA). The Earth has been warming out of the LIA for 300 years. So, the first decade of the 19th century was colder than the first decade of the 20th century that was colder than this first decade of the 21st century. (Around 1700, Londoners used to have “Ice Fairs” on the frozen Thames each year. The last Ice Fair was held in 1814, and the Thames has not frozen solid since.) Having explained that the Earth has been warming from the cold LIA, I said, “Nobody knows if the decade-long halt to global warming is temporary, but the following points warrant consideration.” etc.
The halt to recovery from the LIA that happened in 1998 does not support claims of AGW; indeed, it provides doubt to those claims. But that recovery may resume in future. Please read my explanation of that, too.
You then make bold assertions, saying;
“Levels of CO2 in the atmosphere have increased by at least 30 percent over the past 200 years, almost all due to human activities. CO2 has the effect of retaining heat in the atmosphere, hence the warming.”
Several publications including an analysis I co-authored and a report of the UN Intergovernmental Panel on Climate Change (IPCC) state that available data does not – repeat, not – support a claim that the rise in atmospheric CO2 concentration is “almost all due to human activities”. I explain this as follows.
The data concerning atmospheric carbon dioxide concentrations in past centuries are hotly disputed. Many direct measurements of atmospheric carbon dioxide concentration in the nineteenth century showed higher atmospheric CO2 levels than now. Stomata data indicate that similar atmospheric CO2 levels to now have repeatedly existed in recent previous centuries. But ice core data do not show such high values. This may be due to smoothing of concentration peaks in the ice during its formation or merely because – as Neftel reports – he and others who analyse the data reject all values higher than the assumed 280 ppmv pre-industrial level because “high” values are assumed to be contamination.
Since the late 1950s the Keeling series of atmospheric CO2 concentration measurements has been conducted on the side of the active Mauna Loa volcano. And other series have also been accumulated elsewhere since then. They indicate ~30% rise in atmospheric CO2 concentration since 1958.
I and co-workers used the Keeling series in our assessment of possible causes of the rise in atmospheric CO2 concentration increase. In my first posting here I cited a URL where you can hear a presentation of that work. We concluded;
“Hence, using the available data it cannot be known what if any effect altering the anthropogenic emission of CO2 will have on the future atmospheric CO2 concentration. This finding agrees with the statement in Chapter 2 from Working Group 3 in the IPCC’s Third Assessment Report (2001) that says; “no systematic analysis has published on the relationship between mitigation and baseline scenarios”.(9)”
Please note that the IPCC says “no systematic analysis has published on the relationship between mitigation and baseline scenarios”. In other words, the IPCC states that available data does not support your claim that the rise in atmospheric CO2 concentration is “almost all due to human activities”.
Your assertion that, “CO2 has the effect of retaining heat in the atmosphere, hence the warming” is so wrong that there is not room to provide a full refutation of it here. Suffice it to say there are several other explanations of recent warming. For example, clouds reflect solar heat and a mere 2% increase to cloud cover would more than compensate for the maximum possible predicted warming due to a doubling of carbon dioxide in the air. Good records of cloud cover are very short because cloud cover is measured by satellites that were not launched until the mid 1980s. But it appears that cloudiness decreased markedly between the mid 1980s and late 1990s. Over that period, the Earth’s reflectivity decreased to the extent that if the Sun were constant then the reduced cloudiness provided an extra surface warming of 5 to 10 Watts/sq metre. This is a lot of warming. It is between two and four times the entire warming estimated to have been caused by the build-up of human-caused greenhouse gases in the atmosphere since the industrial revolution. (The IPCC says that since the industrial revolution, the build-up of human-caused greenhouse gases in the atmosphere has had a warming effect of only 2.4 W/sq metre).
Your concluding assertions to me say;
“On a geological scale, this is very fast warming. A warming gas is unstable, hence the concern over the long-term effects. The safest and most effective way of mitigating the warming is to reduce emissions of CO2.”
There is no evidence that “On a geological scale, this is very fast warming”. Indeed, if the CO2 is responsible for the recent warming then it is certainly not “very fast”.
The warming of the twentieth century was during two periods of 1910 to 1940 and 1970 to 1998. The rate of warming was very similar in both periods: indeed, the warming rate was slightly higher in the earlier period. But more than 80% of the human emissions were after 1940. So, it cannot be said that any warming induced by the emissions is “very fast” because warming was less fast in the warming period after 80% of the emissions than in the previous warming period.
And CO2 is a very stable.
There is no reason to suppose that reducing the emissions of CO2 would mitigate the warming. As I quote and reference above, even the IPCC says “no systematic analysis has published on the relationship between mitigation and baseline scenarios”.
And such reduction to the emissions would not be “safe” or “safest”. It would kill millions of people (mostly children). Indeed, the Precautionary Principle says it should not be done.
Constraint of CO2 emissions would inhibit use of fossil fuels with resulting economic damage. The effects would be worse than the ‘oil crisis’ of the 1970s because the constraints would need to be more severe, they would be permanent, and energy use has increased since then. The economic disruption in the developed world would disrupt economic activity everywhere. The major effects would be in the developed world because it has the largest economies. But the worst effects would be on the world’s poorest peoples: people near to starvation are starved by disrupted economic activity. And this in a probably futile to attempt to affect the climate of the entire world.
So, the Precautionary Principle states that we should not accept the certain risks of certain economic disruption in attempt to modulate the world’s climate on the basis of assumptions that have no supporting evidence and merely because they have been described using computer games.
I hope these answers to your points are sufficient. And I again thank you for attempting dialogue and not abuse.
Richard
