In addition, volcanoes generally cause global cooling through the emissions of cloud-forming sulfur dioxide and water-cycle feedback.
Once again this is probably an over-simplification.
"Climate modeling following the eruption of Mount Pinatubo in the Philippines in 1991 (using both aerosol and non-aerosol starting inputs) produced a general cooling of the troposphere (the band of the atmosphere where most clouds circulate), but also, the models yielded a pattern of winter warming of surface air temperature over the Northern Hemisphere. Dual effects such as these complicate longer-term climate impact predictions.
To what extent this tropospheric cooling is mitigated or “canceled out” by other sources of warming, such as from solar activity, build-ups of CO2 and other greenhouse gases, and long-term variation in Milankovitch cycling (currently only one cycle, precession, favors glaciation), depends on the timing and duration of all these factors, and makes for the highly complex science that is climatology."
Planetsave (
Volcanoes: The ‘X Factor’ in Climate Change | Planetsave)
The same website also says, "Numerous volcanoes presently active and erupting across the planet will impact short-term warming and climate change. Longer-term impacts are unknown."
In other words, the jury is still very much out on how much natural forces are also impacting the observable climate changes. Some changes attributed to man-made emissions might very well be (at least partially) due to other natural inputs also.
I do not deny that man made pollution has been a problem since the industrial revolution and we should be making efforts to reduce it. But how about making the changes where they are needed?
The jury is still out on whether CO2 is actually a 'problem.' Yes, there might be a considerable number of people and even some governments who tow that line and once upon a time there were a considerable number of people (scientists included) who believed the earth was flat and that the sun revolved around the earth also. I say, even still,
even if CO2 is a problem, Australia's net contribution of 576 million tonnes of carbon dioxide equivalent is only
1.5 percent of world emissions! In any computation of cost vs return, one seriously has to ask whether there will be any measurable return on the enormous cost that the carbon tax imposes on Australians. Not only that, but the deck is stacked so that the biggest players (industry) get compensated to keep on doing what they have always done while the smaller fish in the pond have to caugh up.
There are those like peterc005 who will happily pay his tax and exhibit no change in his emissions behaviour (essentially nullifying the point of having a tax to alter people's emissions behaviour), while others will get compensated to make them feel that they are not out of pocket for the tax either (at least for this year, and also essentially nullifying the point of having a tax to alter people's emissions behaviour). So with everyone maintaining their behaviour while the tax man goes around with his hand out makes no sense at all to me. I'm sure the net effect on our 1.5% contribution to global man-made CO2 will be even less, and the net effect on a global scale will not even register. Meanwhile, back on planet weird, everything now costs more for no good reason because no one is capable of stopping the ALP/Greens policy freight train.