|Image source: The Encyclopedia of Earth
But while there is no such thing as a greenhouse gas, atmospheric carbon dioxide does affect the Earth's temperature by absorbing infra-red radiation, or heat. In particular, it absorbs some, a very small amount, of the heat that the Earth radiates to space. When global temperature is constant, the Earth radiates to outer space an amount of energy exactly equal to the amount it receives from the sun. If the atmospheric carbon dioxide concentration is raised, a tiny additional fraction of the heat emitted by the Earth in the direction of the sky is absorbed by the newly added carbon dioxide, thus warming the planet. As the Earth warms, it emits an increasing amount of heat to space until a new balance between incoming and outgoing radiation is reached.
In terms of climate, therefore, the significance of carbon dioxide is that it is a heat absorbing gas. But it is not a very powerful heat absorbing gas. Water vapor, for example, absorbs heat radiation about ten times as strongly as carbon dioxide and occurs in the atmosphere at a concentration about ten times that of carbon dioxide. Methane, or natural gas, is an even more powerful heat absorbant than carbon dioxide (one hundred times more powerful), and it leaks to the atmosphere in massive quantities from gas pipelines, oil drilling operations, and many natural sources.
So, yes, rising atmospheric carbon dioxide concentrations will, all other things being equal, cause some climate warming. But all other things will never be equal. And many of the other things that are not equal are subject to human influence. Particles of black carbon or soot, for example, injected into the atmosphere by diesel powered vehicles, oil-burning ships, and forest fires, absorb heat and may be as significant as carbon dioxide in accounting for any human-caused climate change. But sulfur emitted to the atmosphere by the combustion of coal, for example, gives rise to white sulfate particles, which reflect sunlight and thus cool the planet. Sulfate particles also seed cloud formation, and clouds have a huge impact on global temperature in many and complex ways, some tending to raise global temperature, some having the opposite effect. There's also the impact of human activity on the surface features of the planet. Deforestation, for example, has a long-term cooling effect, because trees reflect less solar energy back to space than do bare ground or agricultural crops, but in the short run, deforestation may have a warming effect by causing the transfer of carbon from the biosphere to the atmosphere.
So, no, the science of climate change is not settled, and when Al Gore says it is he only demonstrates that, scientifically, he is a moron. Either that, or he sees the global warming scare a means to psych the semi-educated American and European populations to regard themselves as some kind of disease on the planet, with a moral obligation to commit racial suicide by having no children. That is what the elite desire and what they promote. What, after all, in this age of automation, is the use of the consuming masses: best be rid of them.
CanSpeccy: Rising Atmospheric Carbon Dioxide Concentration, Part IV: Reversing the Trend
CanSpeccy: Rising Atmospheric Carbon Dioxide Concentration, Part III: Induced Stupidity and the Decline of the West
CanSpeccy: Rising Atmospheric Carbon Dioxide Concentration, Part II: Ecosystem Disruption