Global Warming: Who Said It's Over?

Recently such proponents of Global Warming as Al Gore have declared victory and announced the debate over. Well, the debate isn't as over as it would seem. Below I have listed both sides of the argument, and I would be interested in hearing opinions from the Peanut Gallery.

Listed here are some of the assertions made by supporters and opponents of the hypothesis of anthropogenic global warming. Assertions are included solely because they have been made by one side or the other, without comment on their scientific validity or lack thereof.

Assertions by supporters
Supporters of the anthropogenic global warming hypothesis assert that:

• The fact that carbon dioxide absorbs and emits IR radiation has been known for over a century.[34]
• Gas bubbles trapped in ice cores give us a detailed record of atmospheric chemistry and temperature back more than eight hundred thousand years,[35] with the temperature record confirmed by other geologic evidence. This record shows a correlation between atmospheric carbon dioxide and temperature.[36]
• The recent rise in carbon dioxide and other greenhouse gases is greater than any in hundreds of thousands of years[37] and this is human-caused, as shown by the isotopic signature of CO2 from fossil fuels.
• The historical temperature record shows a rise of 0.4–0.8 °C over the last 100 years.[38]
  The current warmth is unusual in the past 1000 years (see Temperature record of the past 1000 years).
• Climate change attribution studies, using both models and observations, find that the warming of the last 50 years is likely caused by human activity; natural variability (including solar variation) alone cannot explain the recent change.
• Climate models can reproduce the observed trend only when greenhouse gas forcing is included.[39]
• The IPCC reports correctly summarize the state of climate science.
  Humankind is performing a great geophysical experiment, and if it turns out badly—however that is defined—we cannot undo it. We cannot even abruptly turn it off. Too many of the things we are doing now have long-term ramifications for centuries to come.[40]
• Climate models predict more warming, sea level rise, more frequent and severe storms, drought and heat waves, spread of tropical diseases, and other climactic effects in the future.
• The current warming trend will accelerate when melting ice exposes more dark sea and land that will reflect less sunlight; and when the tundra thaws and releases large quantities of trapped greenhouse gases.[41]
• Atlantic hurricane trends have been recently linked to climate change.
• The Precautionary principle requires that action should be taken now to prevent or mitigate warming.
• Proponents of the anthropogenic global warming hypothesis tend to support the IPCC position, and thus represent the scientific consensus (though with considerable differences over details, and especially over what action should be taken).
  
  Assertions by opponents

Some of the assertions made in opposition to the hypothesis of anthropogenic global warming include:

• IPCC draws firm conclusions unjustified by the science, especially given the acknowledged weakness of cloud physics in the climate models.[60][61]
• The influential "Hockey Stick" study by Mann has been shown to contain errors .
  Using "consensus" as evidence is an appeal to the majority argument rather than scientific discussion. Some have proposed that, because the issue has become so politicized, climatologists who disagree with the consensus may be afraid to speak out for fear of losing their positions or funding. [62]
• Climate models will not be able to predict the future climate until they can predict solar and volcanic activity, [63] changes in sea temperature [64], and changes to cosmic ray levels that make the low level clouds that cool the earth [65], and take into account other recently discovered feedback mechanisms.
• Water vapor, not CO2, is the primary greenhouse gas. Depending on the referenced source, water vapor and water droplets account for 36-70% of the greenhouse effect, while CO2 accounts for 9-26%.
• Global warming is largely a result of reduced low-altitude cloud cover from reduced Galactic cosmic rays (GCRs). It is similar in concept to the Wilson cloud chamber but on a global scale, where earth's atmosphere acts as the cloud chamber.
• The concern about global warming is analogous to the concern about global cooling in the 1970s. The concern about global cooling was unnecessarily alarmist. Therefore, the concern about global warming is equally alarmist.
• The Medieval warm period, which lasted from the 10th to the 14th century, had above-average temperatures for at least Western Europe, and possibly the whole Earth. This period was followed by the Little Ice Age, which lasted until the 19th century, when the Earth began to heat up again.
• Satellite temperature records show less warming than surface land and sea records.
  The relationship between historic temperatures and CO2 levels, based on ice-core samples, shows that carbon dioxide increases have always followed a rise in temperature rather than the other way around. [66]
• Climatic changes equal to or even more severe than those on Earth are also happening on other bodies within this solar system, including Mars, Jupiter, Pluto and Triton. [67]
  Opponents tend to define themselves in terms of opposition to the IPCC position. They generally believe that climate science is not yet able to provide us with solid answers to all of the major questions about global climate. Opponents often characterize supporters' arguments as alarmist and premature, emphasizing what they perceive as the lack of scientific evidence supporting global-warming scenarios.

Many opponents also say that, if global warming is real and man-made, no action need be taken now, because:

• Future scientific advances or engineering projects will remedy the problem before it becomes serious, and do it for less money.
• A small amount of global warming would be benign or even beneficial, as increased carbon dioxide would benefit plant life, thus potentially becoming profitable for agriculture world-wide.
• There is a distinct correlation between GDP growth and greenhouse-gas emissions. If this correlation is assumed to be a causation, a cutback in emissions might lead to a decrease in the rate of GDP growth [68].