I'll try not to reveal my power-level this early in the morning, but suffice to say that all the anti-climate-change arguments in this thread are just rehashes of already-debunked arguments.
"Climate change does not exist because we're undergoing a natural temperature/CO2 cycle"
[1] [2]Is global warming a natural cycle? Or is global warming affected by human influence? What does the science say? Both are true. In the natural cycle, the world can warm, and cool, without any human interference. For the past million years this has occurred over and over again at approximately 100,000 year intervals. About 80-90,000 years of ice age with about 10-20,000 years of warm period, give or take some thousands of years.
The difference is that in the natural cycle CO2 lags behind the warming because it is mainly due to the Milankovitch cycles. Now CO2 is leading the warming. Current warming is clearly not natural cycle.
"Climate change exists but does not have any meaningful negative effects"
[1] [2]Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 percent.
Between 2030 and 2050, climate change is expected to cause approximately 250 000 additional deaths per year, from malnutrition, malaria, diarrhoea and heat stress.
The direct damage costs to health (i.e. excluding costs in health-determining sectors such as agriculture and water and sanitation), is estimated to be between US$ 2-4 billion/year by 2030.
"Climate change doesn't exist because Al Gore falsely predicted a bunch of doomsday stuff would happen"
I don't have an authoritative source on this one, but Al Gore is not a scientist and the majority of actual climate scientists are not predicting Armageddon in a matter of decades. They're confident that bad stuff will happen, but the consequences shown in An Inconvenient Truth don't necessarily reflect the scientific consensus.
edit: There have been climate scientists that have gone out and criticized some of the catastrophic outcomes Al Gore talks about in his book/movie.
[1]One concern among scientists in the film was the connection between hurricanes and global warming, which remains contentious in the science community. Gore cited five recent scientific studies to support his view.[38] "I thought the use of imagery from Hurricane Katrina was inappropriate and unnecessary in this regard, as there are plenty of disturbing impacts associated with global warming for which there is much greater scientific consensus," said Brian Soden, professor of meteorology and oceanography at the University of Miami.
Though, I wouldn't be too hard on Al Gore. For a non-scientist, he actually conveyed the science surprisingly accurately, and he deserves credit for starting a modern, science-based dialog on environmentalism.
