Other Answers (15)

• Yes indeed, you are wrong. The CO2 output (e.g. %26quot;hot air%26quot;) coming from the %26quot;left%26quot; and %26quot;right%26quot; (it would bias the data too much if we didn%26#039;t include the %26quot;hot air%26quot; of people like Rush Limbaugh) could not possibly be responsible for the 100+ ppm atmospheric CO2 rise since pre-industrial times.
  
  When you also consider the fact that isotope analysis of the atmospheric CO2 demonstrates conclusively that it comes from fossil fuel sources, the truth becomes clear.
  
  Greenhouse gases have always kept the planet warmer (by about 31 C) than it would be without them. Humans (including CO2 coming out of some big mouths, but mainly from power generation and transportation) have raised the level of greenhouse gases significantly. Therefore, the planet is warming up.
  
  It%26#039;s really quite simple. All one has to do to understand the reality of AGW is to put their anti-environmental Al-Gore-hating Rush-Limbaugh-Dittohead-loving Government-conspiracy bias away for a few moments and look honestly at the evidence from actual climate scientists.
  
  We know it%26#039;s warming, and we%26#039;ve measured how much:
  
  http://www.epa.gov/climatechange/science...
  
  Scientists have a good idea how the Sun and the Earth%26#039;s natural cycles and volcanoes and all those natural effects change the global climate, so they%26#039;ve gone back and checked to see if they could be responsible for the current global warming. What they found is:
  
  Over the past 30 years, all solar effects on the global climate have been in the direction of (slight) cooling, not warming. This is during a very rapid period of global warming.
  
  http://news.bbc.co.uk/2/hi/uk_news/62902...
  http://www.pubs.royalsoc.ac.uk/media/pro...
  
  A recent study concluded:
  
  “the range of [Northern Hemisphere]-temperature reconstructions and natural forcing histories…constrain the natural contribution to 20th century warming to be %26lt;0.2°C [less than one-third of the total warming]. Anthropogenic forcing must account for the difference between a small natural temperature signal and the observed warming in the late 20th century.”
  
  http://www.pnas.org/cgi/content/full/104...
  
  You can see this in the third graph here, where the dotted lines are just from natural causes, and the full lines are natural + human causes:
  
  http://www.pnas.org/content/vol104/issue...
  
  If that’s not enough to convince you the Sun isn’t responsible, consider the fact that no scientific study has ever attributed more than one-third of the warming over the past 30 years to the Sun, and most attribute just 0-10% to the Sun.
  
  http://answers.yahoo.com/question/index;...
  
  So the Sun certainly isn%26#039;t a large factor in the current warming. They%26#039;ve also looked at natural cycles, and found that we should be in the middle of a cooling period right now.
  
  %26quot;An often-cited 1980 study by Imbrie and Imbrie determined that %26#039;Ignoring anthropogenic and other possible sources of variation acting at frequencies higher than one cycle per 19,000 years, this model predicts that the long-term cooling trend which began some 6,000 years ago will continue for the next 23,000 years.%26#039;%26quot;
  
  http://en.wikipedia.org/wiki/Milankovitc...
  http://www.sciencemag.org/cgi/content/ab...
  
  So it%26#039;s definitely not the Earth%26#039;s natural cycles. They looked at volcanoes, and found that
  
  a) volcanoes cause more global cooling than warming, because the particles they emit block sunlight
  
  b) humans emit over 150 times more CO2 than volcanoes annually
  
  http://volcano.und.edu/vwdocs/Gases/man....
  
  So it%26#039;s certainly not due to volcanoes. Then they looked at human greenhouse gas emissions. We know how much atmospheric CO2 concentrations have increased over the past 50 years:
  
  http://en.wikipedia.org/wiki/Image:Mauna...
  
  And we know from isotope ratios that this increase is due entirely to human emissions from burning fossil fuels. We know how much of a greenhouse effect these gases like carbon dioxide have, and the increase we%26#039;ve seen is enough to have caused almost all of the warming we%26#039;ve seen over the past 30 years (about 80-90%). You can see a model of the various factors over the past century here:
  
  http://en.wikipedia.org/wiki/Image:Clima...
  
  This is enough evidence to convince almost all climate scientists that humans are the primary cause of the current global warming.