The truth is very different. Most of the media articles you will see refer to reports issued by the IPCC. The IPCC is the Intergovernmental Panel on Climate change, a political body appointed by the UN. Many of the 3,000 members of this panel are not scientists, but simply political appointees. The few real scientists on the panel have disputed the panel's findings but have been silenced by having their comments deleted from the reports.
Several of these scientists have asked to have their names removed from the IPCC report, but have had their requests denied. Several have actually sued the panel to have their names removed, but few have been successful.
The actual fact regarding consensus on this issue is that there are many more scientists who dispute the claims regarding global warming than there are who support them.
The IPCC reports rely on a particular computer model which projects temperature changes due to "positive feedback" reactions in the atmosphere. The IPCC report claims that as CO2 levels rise, temperatures will also rise causing more water to be evaporated into the air. Since water vapor is by far the leading greenhouse gas, increased water vapor is supposed to accelerate the global warming process in a runaway feedback loop. The actual scientific data, however, do no support the positive feedback model. The basic methodology used by the IPCC cannot be supported by actual data so the panel relies on the news media to filter the news that reaches the public. This article is an attempt to set the public record straight.
The link I have provided here will take you to a petition, signed by over 17,200 scientists who think that the currently available scientific data do not support the conclusion that global warming is anything other than a naturally occurring cyclic phenomenon. The site also contains a peer reviewed scientific paper that gives an overview of the existing climate science. This peer reviewed paper demonstrates that the positive feedback model is not valid and that therefor, the entire hypothesis of man-made global warming is also not validated.
Here are a few quotes from the paper and the petition:
The empirical evidence actual measurements of Earth's temperature shows no man-made warming trend. Indeed, over the past two decades, when CO2 levels have been at their highest, global average temperatures have actually cooled slightly.
Regarding carbon dioxide in the atmosphere:
The observed increases are of a magnitude that can, for example, be explained by oceans giving off gases naturally as temperatures rise. Indeed, recent carbon dioxide rises have shown a tendency to follow rather than lead global temperature increases.
Follow, rather than lead? Yes that is what the data show. In Al Gore's famous ice core data, showing the supposed correlation between temperature and CO2, what he neglected to say was that there was an 800 year time lag between a rise in global temperatures and the following rise in CO2. Yes, temperature goes up 800 years before CO2 levels rise.
Global warming alarmists claim that the temperatures we are seeing now are the highest in several thousand years. The science actually shows that:
During the Medieval Climate Optimum, temperatures were warm enough to allow the colonization of Greenland. These colonies were abandoned after the onset of colder temperatures. For the past 300 years, global temperatures have been gradually recovering . ... they are still a little below the average for the past 3,000 years. The human historical record does not report ''global warming'' catastrophes, even though temperatures have been far higher during much of the last three millennia.
The paper also presents a large amount of temperature measurement data, from a variety of sources, such as balloon and satellite, all of which show a slight downward trend in global temperatures, not a rise as would be expected from the IPCC computer models.
Disregarding uncertainties in surface measurements and giving equal weight to reported atmospheric and surface data and to 10 and 19 year averages, the mean global trend is minus 0.07 ºC per decade.
In short, the findings presented in the paper are:
The global warming hypothesis has been thoroughly evaluated. It does not agree with the data and is, therefore, not validated.
As for the coming disaster scenarios presented by the global warming advocates, such as sea levels rising:
The reported current global rate of rise amounts to only about plus 2 mm per year, or plus 8 inches per century, and even this estimate is probably high . The trends in rise and fall of sea level in various regions have a wide range of about 100 mm per year with most of the globe showing downward trends.
Most of the globe showing "downward trends?" Interesting. I will also tell you that by personal experience as a sailor, water levels aren't rising anywhere that I have sailed, and I have sailed from the Atlantic Ocean, to the Great Lakes to the Gulf of Mexico. The Great Lakes are actually falling significantly.
How about the claim that severe weather is increasing due to global warming?
Similarly, claims that hurricane frequencies and intensities have been increasing are also inconsistent with the data. Figure 16 shows the number of severe Atlantic hurricanes per year and also the maximum wind intensities of those hurricanes. Both of these values have been decreasing with time.
As temperatures recover from the Little Ice Age, the more extreme weather patterns that characterized that period may be trending slowly toward the milder conditions that prevailed during the Middle Ages, which enjoyed average temperatures about 1 ºC higher than those of today.
The paper concludes with statements like:
There are no experimental data to support the hypothesis that increases in carbon dioxide and other greenhouse gases are causing or can be expected to cause catastrophic changes in global temperatures or weather. To the contrary, during the 20 years with the highest carbon dioxide levels, atmospheric temperatures have decreased.
We also need not worry about environmental calamities, even if the current long-term natural warming trend continues. The Earth has been much warmer during the past 3,000 years without catastrophic effects. Warmer weather extends growing seasons and generally improves the habitability of colder regions. ''Global warming,'' an invalidated hypothesis, provides no reason to limit human production of CO2, CH4, N2O, HFCs, PFCs, and SF6 as has been proposed.
The Petition Project Site also includes a petition to the US Congress. The wording of the petition is:
We urge the United States government to reject the global warming agreement that was written in Kyoto, Japan in December, 1997, and any other similar proposals. The proposed limits on greenhouse gases would harm the environment, hinder the advance of science and technology, and damage the health and welfare of mankind.
There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gasses is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate. Moreover, there is substantial scientific evidence that increases in atmospheric carbon dioxide produce many beneficial effects upon the natural plant and animal environments of the Earth.
Given the fact that over 17,200 scientists have signed this petition, I would have to say that there certainly is no consensus among scientists that global warming is real or that it is man made. Those who promote the global warming hypothesis have a political agenda, not a scientific one. They are on a malicious mission to shut down the world's industrial societies and prevent the 4 billion or so human beings living in the third world from ever improving their condition. I find this to be unconscionable and inhuman. I condemn these people.
Perhaps it may be as simple as Michael Crichton said in his book "State of Fear." The politicians of the world have a vested interest in keeping the people in a state of fear. It enables the politicians to continually undermine the freedoms and rights of the people in the name of making them safe.
For myself, I side with Benjamin Franklin who said "Those who will sacrifice essential liberty for the promise of safety deserve neither liberty nor safety, and neither is what they will have."