“CO2 is going to turn the climate of Earth into an oven. We’re all gonna bake and die.”
– Exaggeration. Average global temperature will increase. Some localities may get colder: cutting down trees near polar latitudes makes those areas cooler, whereas cutting down trees near the equator increases temperature in the tropics. This change in local temperature is directly related the photosynthesis of plants, which is implicitly and directly related to the concentration of CO2 in the atmosphere. Also, the trend is towards more extreme, erratic, and unusual weather patterns across the globe. For example: increased drought in the tropics, more and stronger hurricanes generated by warmer ocean surface water.
“We might have raised the temperature by 1/10 of 1 degree – maybe.”
– Wrong. Average global temperature has increased by 0.8 degrees Celsius since the beginning of the Industrial Revolution. Earth has warmed 1° Celsius since 1500, half of it in last 100 years. The global temperature is presently increasing at the rate of 0.2 degrees Celsius per decade. If current emissions rates continue to rise, we could warm another one degree Celsius by 2050, which would threaten civilization, and lead to runaway global warming. A concentration greater than 450 ppm of carbon dioxide in the Earth’s atmosphere will lead to a runaway greenhouse effect that will threaten all life on Earth. The atmosphere’s temperature works in a positive feedback loop. The warmer the atmosphere gets, the more the rate at which the atmosphere warms increases. Once that happens, there is no stopping it. Carbon Dioxide is increasing at the rate of 2.5 parts per million each year; at this rate carbon dioxide levels will exceed 400 parts per million by the year 2014. This is a level not seen by the Earth for several hundred thousand years.
“CO2 is a natural compound in the atmosphere. It’s not a pollutant. Plants have to have it…I breathe out. I create it. It is no big deal. And it’s certainly not going to end the world.”
– Misleading. The CO2 people breathe out is not the problem at all. Fossil fuels, deforestation, and combustion reactions are the main problem. CO2 itself is not a pollutant, but higher percentages of it are a problem because more solar heat gets trapped – hence, why it is called a greenhouse gas.
Two-thirds of the carbon dioxide entering the Earth’s atmosphere comes from natural sources such as animal respiration and volcanoes, while one-third is anthropogenic (caused by humans). The sun’s effect has also been demonstrated to be insignificant: over the past 50 years, the troposphere (layer of atmosphere next to Earth’s surface) has been steadily warming while the stratosphere has been steadily cooling. This is the opposite of what would be expected if the sun were having a pronounced effect on Earth’s warming. However, due to human activities such as the combustion of fossil fuels and deforestation, the concentration of atmospheric carbon dioxide has increased by about 36% since the beginning of the Industrial Revolution.
In addition to data from tree rings, there are also of measurements of the 13C/12C ratio in the CO2 trapped in ice cores. The tree ring and ice core data both show that the total change in the 13C/12C ratio of the atmosphere since 1850 is about 0.15%, which is very large relative to natural variability. The results show that the full glacial-to-interglacial change in 13C/12C of the atmosphere — which took many thousand years — was about 0.03%, or about 5 times less than that observed in the last 150 years.
Another, quite independent way that we know that fossil fuel burning and land clearing specifically are responsible for the increase in CO2 in the last 150 years is through the measurement of carbon isotopes. CO2 produced from burning fossil fuels or burning forests has quite a different isotopic composition from CO2 in the atmosphere. This is because plants have a preference for the lighter isotopes (12C vs. 13C); thus they have lower 13C/12C ratios. Since fossil fuels are ultimately derived from ancient plants, plants and fossil fuels all have roughly the same 13C/12C ratio – about 2% lower than that of the atmosphere. As CO2 from these materials is released into, and mixes with, the atmosphere, the average 13C/12C ratio of the atmosphere decreases.
The cost of avoiding the worst impacts of climate change can be limited to 1 percent of economic output while doing nothing could lead to damage costing as much as 20 percent of the world’s gross domestic product. By 2050, when the global population will be an estimated 9 billion people, per-capita gas emissions will need to have fallen to about 2 tons a year, compared with levels as high as 20 tons a person currently in the U.S.
“It’s no different than water vapor.”
– Completely false! Carbon dioxide is CO2; water vapor is H20. CO2 is heavier than H2O, and can’t hydrogen bond. It has a completely different chemistry than water vapor. In fact, they only thing they have in common is that they both contain atoms, and are both gases in standard conditions.
“[CO2] is just a substance that’s out there.”
– Non-point. Neurotoxins are “out there”, too. Does that automatically mean they’re healthy? Are you going to go breathe sulfur dioxide because it’s also “out there”?
The rest is ad hominem attacks making people who accept the evidence for global warming look like unquestioning and intolerant religious fanatics – they were even called “freaks” by the host.