1) "We have reliable weather statistics for only four centuries - far too short a period to make overarching judgments" - this is true. The information is from many different sources and with something like temperature (which changes locally and frequently) there are understandable problems with measurements based on secondary data from several hundred years ago (i.e. before we started measuring temperature directly).
2) "Geological evidence shows there have been violent shifts in the Earth's temperature in the distant past, so man can't be held solely responsible for dramatic changes in life. Scaremongers posit the ideal of a changeless world, but nothing stays the same" - true, but it still possible that humankind produced a small change that was unprecedented, and as such will have unprecedented consequences.
One of the problems with the current global warming debate is the combination of environmentalist ideologies and ideas of serious global warming amelioration. By this I mean whenever someone comes up with more evidence that global warming is happening and is a serious issue, they have to shout over the eschatologists, doom-mongers, green fundamentalists and other riff-raff who pollute the debate.
It is good that politicians are finally taking part in the debate, but it does rather seem that appearing "green" is more of a career move as opposed to a deeply-held conviction (c.f. David Cameron).
Then you have someone like Freeman Dyson, whose credentials as an actual scientist as opposed to a politician or commentator are impeccable. His recent comments on the paucity of real-world, as opposed to computer model, data to support the current "consensus" (not a word we should be comfortable with when concerned with something as potentially problematic as rapid climate change) of anthropogenic global warming.
Dyson could almost be the individual being satirised (I'm sure it is a spoof, [
"My optimism about the long-term survival of life comes mainly from imagining what will happen when life escapes from this planet and becomes adapted to living in vacuum. There is then no real barrier to stop life from spreading through the universe. Hopping from one world to another will be about as easy as hopping from one island in the Pacific to another. And then life will diversify to fill the infinite variety of ecological niches in the universe, as it has done already on this planet."
This ties into my point that once we create a stable, self-sustaining, self-repairing, and (hopefully) benign technosphere it will evolve independently of basic homo-sapiens. It will then spread across the universe, bringing life, wonder, joy and happiness. If and when such a thing does happen it will probably be a little different, but it will still be worth watching.
Dyson goes on to comment on global warming:
"Concerning the climate models, I know enough of the details to be sure that they are unreliable. They are full of fudge factors that are fitted to the existing climate, so the models more or less agree with the observed data. But there is no reason to believe that the same fudge factors would give the right behavior in a world with different chemistry, for example in a world with increased CO2 in the atmosphere."
This seems to be the underlying argument of most people who deny that anthropogenic global warming is a significant factor in the current trend. I am not qualified to comment on any of the issues concerned, but I do so anyway. What other use has blogging?
This issue bugs me because there seems to be so much controversy and politicking surrounding a simple question: "are human activities the cause of global warming?" It has reached the point where I'm less and less confident in expressing any opinion. I'm almost inclined to just sit back and wait for confirmation either way, but that would be lazy and thoughtless.
Maybe one day I'll know enough to know the answer. Sooner or later we'll find out. Right now we need to be concerned for the lives and livelihoods of those who will suffer because the of direct and indirect consequences of this global temperature rise, regardless of whether it is caused by people or not.