I have never been particularly interested in this issue but there is now so much media coverage about it, I thought I'd better do some research to find some answers.
I came across junkscience.com among others and read a few articles. This is where I currently stand:
1. The average temperature of the Earth has increased by around 0.6 C since 1880
So the globe is in fact warming.
And as a_unique_person said, global averages are not all that matter. If the temperature in the arctic increases by 2
oC while it decreases by the same amount elsewhere then the average would stay the same, but the ice would still melt.
2. At least half of this increase can be attributed to increased solar activity
As a_unique_person says, simply not true. The change in average energy recieved from the Sun over the last hundred years is insignificant compared with that from annual variations, and yet we can see no effects from these. The interesting observation that leads to these claims is that there seems to have been a correlation between the cycle of ice ages and the Sun's activity. No mechanism is known that could cause this, although the best current theory is that a more active Sun pushes the heliopause further out and so affects the number of cosmic rays that reach the Earth. This is very speculative however, and, even if true, would have very little relation to any small changes over the past century.
Another observation is that the Sun seems unsually peaceful compared to other similar stars, and it is quite possible that it went through periods of much higher activity in the past. This could explain past climate variations, but, again, is not related to the current changes.
3. CO2 is not a major factor in "greenhouse" gases or global warming
CO
2 is nowhere near a potent as many other gases, but it is one of the most abundant, after oxygen and nitrogen. It is also the one that is being most affected by humans. Yes, other gases could have larger effects, but since we are not doing much to change their concentration we do not generally have to worry about them. CO
2 is something we can see changing and something we know we can do something about.
4. There is no evidence to suggest recent warming is due to man-made factors
Again, as a_unique_person says, this is simply not true. Pirates aside, there is a very clear correlation between the amount of fossil fuels burnt, the amount of CO
2 in the atmosphere and the amount of global warming. Whether there is actual cause is not proven, but to say there is no evidence is just wrong.
5. The planet would generally be better off with a slight increase in temperature than a slight decrease
This is just plain ridiculous. We know the environment is relatively stable at the moment. Any change in temperature would change this, and all the models we have at the moment say this would cause massive change in climate that will have severe effects on all life. If we assume our models are hopelessly inaccurate then we cannot predict what will happen and can say nothing about how "good" it would be.
As an even more important point, better for who (or possibly whom)? The planet is a lump of rock and really doesn't care what it's temperature is. All life on it is adapted to the current environment, so any change will be for the bad, at least until things adapt.
6. It is a waste of money and resources trying to cut emissions before gaining a better understanding of climate change
By the time we understand it it will be too late. If we are even close to correct then we need to act as soon as possible. Even if we are not correct, can it really be a bad thing to have a cleaner environment and a more efficient way of life?
I have to add that I am firmly against all the fuss over global warming. We know it is happening because we can see it. The trouble is that even if it is entirely due to humans, I think it is too late to do anything about it. The climate is alredy warming and ice is already melting. Even if we stop producing any CO
2 tomorrow it will not cool the climate down again until long after major changes have happened. In addtion, civilisation has reached a point where it cannot simply turn off all the factories and so there is no chance of us having a noticable effect in the near future. I would also say that as long as there is oil and coal in the ground, someone will dig it up and burn it. The west may be starting to embrace cleaner technology, but the developing world will always opt for the cheapest and easiest solution. Their response to us trying to stop them will always be "You did it, so why shouldn't we?".
I think there are much more important pollution issues that are ignored in the fuss over global warming. CO
2 is not the ony product of industry. There are many pollutants, even just soot and dust, that have very clear links to illness and environmental damage. The debate over global warming leads to these things being largely ignored. I feel that the whole global warming movement actually causes more damage than it prevents by diverting resources from known, and preventable, pollution sources to unclear ones like CO
2.
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