"Please post info that specifically proves that global warming is a product of man and not a cycle the Earth would move through anyway regardless of humans being here or not. " So writes a normally rational correspondant I have known for a long time.
Among the many, many studies and reports available today...
The US National Academy of Sciences, 2001 (and here)
“Greenhouse gases are accumulating in Earth’s atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise. Temperatures are, in fact, rising. The changes observed over the last several decades are likely mostly due to human activities, but we cannot rule out that some significant part of these changes are also a reflection of natural variability.”
Professor Peter Barrett FRSNZ (Director of the Antarctic Centre, Victoria University of Wellington), May 10, 2002
"The claim (that global warming has nothing to do with human activity) denies a huge body of contrary published scientific evidence amassed over the last 15 years. Thus it trivialises this effort, and by implication all science.... A few people are saying that the recent warming could be part of a natural cycle. But a further fact from IPCC. "The present CO2 concentration has not been exceeded in the last 420,000 years." This is based on CO2 concentrations measured directly from Antarctic ice cores, which also record 4 glacial-interglacial cycles over this time period. In fact, IPCC think that there is more CO2 in the air we are breathing now than at any time in the last 20 million years."
American Meteorological Society, February 9, 2003
"There is now clear evidence that the mean annual temperature at the Earth's surface, averaged over the entire globe, has been increasing in the past 200 years. There is also clear evidence that the abundance of greenhouse gases in the atmosphere has increased over the same period. In the past decade, significant progress has been made toward a better understanding of the climate system and toward improved projections of long-term climate change... The report by the IPCC stated that the global mean temperature is projected to increase by 1.4°C-5.8°C in the next 100 years... Human activities have become a major source of environmental change."
BBC News, Feb 17, 2005
The Times of London, Feb 18, 2005
"The debate about whether there is a global warming signal now is over, at least for rational people," said Tim Barnett, of the Scripps Institution of Oceanography in La Jolla, California. "The models got it right. If a politician stands up and says the uncertainty is too great to believe these models, that is no longer tenable."
Joint science academies’ statement: Global response to climate change, June 7, 2005
"There will always be uncertainty in understanding a system as complex as the world s climate. However there is now strong evidence that significant global warming is occurring. The evidence comes from direct measurements of rising surface air temperatures and subsurface ocean temperatures and from phenomena such as increases in average global sea levels, retreating glaciers, and changes to many physical and biological systems. It is likely that most of the warming in recent decades can be attributed to human activities. This warming has already led to changes in the Earth's climate.
"I simply do not see how man is creating more hurricanes," she wrote. "I've been reading the links provided and I don't see the scientific evidence that these are a product of man and not a natural rise in Earth's temperature as part of its natural heating and cooling cycles."
As I stated, the issue is resolved. Humans cause global warming, global warming causes more intense hurricanes.
Meanwhile, Marcel Crok, in the Financial Post, January 27, 2005, spreads the work of Ross McKitrick and Stephen McIntyre - described as "is a professor of economics (and) a mineral exploration consultant" but both actually affiliated with the Fraser Institute.
Crok describes their work as follows: "This undercuts both Mann's supposed proof that human activity has been responsible for the warming of the earth's atmosphere in the 20th century and the ability to place confidence in the findings and recommendations of the influential Intergovernmental Panel on Climate Change (IPCC). The political implication is a serious undermining of the Kyoto Protocol with its worldwide agreements on reducing emissions of carbon dioxide and other greenhouse gases. "
It's a sham article.
False Claims by McIntyre and McKitrick regarding the Mann et al. (1998) reconstruction
The claims of McIntyre and McKitrick regarding the Mann et al (1998) temperature reconstruction have recently been discredited by the following peer-reviewed article to appear in the American Meteorological Society journal, "Journal of Climate":
Rutherford, S., Mann, M.E., Osborn, T.J., Bradley, R.S., Briffa, K.R., Hughes, M.K., Jones, P.D., Proxy-based Northern Hemisphere Surface Temperature Reconstructions: Sensitivity to Methodology, Predictor Network, Target Season and Target Domain, Journal of Climate, in press (2005).
[McIntyre and McKitrick have additionally been discredited in a recent peer-reviewed article by Rutherford et al (2004)].
"On Yet Another False Claim by McIntyre and McKitrick" which discredits the claimed "Monte Carlo" Experiment Results from the Rejected McIntyre and McKitrick comment to Nature]
Note on Paper by McIntyre and McKitrick in "Energy and Environment"
"The recent paper by McIntyre and McKitrick (Energy and Environment, 14, 751-771, 2003) claims to be an "audit" of the analysis of Mann, Bradley and Hughes (Nature, 392, 779-787,
1998) or "MBH98". An audit involves a careful examination, using the same data and following the exact procedures used in the report or study being audited. McIntyre and McKitrick ("MM")
have done no such thing, having used neither the data nor the procedures of MBH98. Thus, it is entirely understandable that they do not obtain the same result. Their effort has no bearing on the work of MBH98, and is no way a "correction" of that study as they claim. On the contrary, their analysis appears seriously flawed and amounts to a gross misrepresentation of the work of
Letters for Climate Change
" I know of no independent scientific group that has found any of McIntyre and McKitrickâ€™s claims to be valid. Nor is that surprising. Energy & Environment is not a peer reviewed scientific journal; it is a journal primarily devoted to policy rather than science that appears to engage in, at most, haphazard review of its articles."
Proxy-based Northern Hemisphere Surface Temperature Reconstructions: Sensitivity to Method, Predictor Network, Target Season, and Target Domain
"The close reproducibility of the MBH98 reconstruction based on both (a) the use of an independent CFR method and (b) the use of the individual proxies used by MBH98 rather than the Multiproxy/PC representation used by MBH98, discredits the arguments put forth by McIntyre and McKitrick (2003) in support of their putative 'correction' to the MBH98 reconstruction."
And a little about the players...
There's more, but I don't have time for this nonsense.
In short, the McIntyre and McKitrick report has been thoroughly repudiated.
And in closing, I would like to say - especially in the wake of the death and destruction wrought by Katrina - that the continued promotion of pseudo-science and outright lies in order to foster global warming scepticism is not merely morally bankrupt, it disgusts and sickens me.
It's time we, at the very least, swept the lies fostered by the Fraser Institute and its ilk from the pages of our newspapers.