Tuesday, December 8th 2009, 1:16 PM EST
This is what I call plain stupid, we have an AGW supporter giving answers on our behalf. No wonder the public are confused about what is going on, why not have a Climate Realists giving answers to questions for AGW!
How can scientists claim to predict climate change over 50 or more years when they can’t even get next week’s weather forecast right?
They can’t tell us in detail. But forecasting climate change is more like forecasting the seasons than the weather. We know winters are cold and summers are warm. Always. And it’s like that with greenhouse gases. Physicists have known for 200 years that gases like carbon dioxide trap heat. These gases are accumulating in the atmosphere, thanks to our pollution. They will heat up the atmosphere just as certainly as the summer sun heats us.
But surely it’s the job of scientists to deal in irrefutable evidence rather than predictions?
Nothing is absolutely certain or irrefutable. We could be hit tomorrow by an asteroid or a mega-volcano that wipes out warming for centuries. But I’d say climate science is a good deal more reliable than most economic predictions, because it is based on natural laws rather than how markets behave.
Anyway, how can they be sure that the earth has warmed in the last few centuries?
It hasn’t. Evidence from tree rings, the pollen in the bottom of lakes, gas bubbles in ice cores and a lot else, all suggests strongly that it was warm 800 or 900 years ago; then cooler during the little ice age; then warmer again in the 19th century. All this was due to explainable natural cycles. But during the second half of the 20th century there was fast global warming for which there are no known natural explanations. Only the known physics of our soaring emissions of greenhouses gases can explain events.
But increases in CO2 follow periods of warming don’t they, not the other way round?
Both are true. The evidence here comes from gas bubbles in ice, which give us a timeline of atmospheric temperatures and CO2 levels. The two go in tandem in and out of the ice ages over hundreds of thousands of years. But temperatures change a few years earlier than CO2. That’s not surprising. The ice ages come and go because wobbles in the Earth’s orbit change solar radiation, heating the earth. So temperature changes first. But a lot of the subsequent warming (or cooling) is due to CO2 switching between the ocean and the atmosphere as a result of the initial temperature change. The world starts to warm because of a wobble; and as it warms, CO2 bubbles out of the oceans, adding to the warming.
Isn’t it a complete myth that the Arctic ice cap is melting?
Haven’t you seen the satellite pictures? It melts every summer, of course. But in recent years the melt has been greater. In 2008, probably for the first time in thousands of years, both the northwest and northeast shipping passages through the Arctic, north of Canada and Siberia, were ice-free.
And hasn’t the world stopped warming since 1998?
Yes. For now. Global temperatures have been more or less stable since the super-warm El Nino year of 1998. Even so, 2009 is expected to be the fourth or fifth warmest year on record. Some researchers predict stable temperatures, or even modest cooling, for another five years or so. This is due to natural cycles in the oceans that affect air temperature. Nobody ever said that man-made global warming would abolish natural cycles. Or if they did, they were dumb. But greenhouse gases are still accumulating in the atmosphere. Once natural cycles move back to a warming phase, global warming will go into overdrive.
If there is warming, isn’t solar radiation really to blame?
Obviously we would be frozen without the sun. But changes in solar radiation cannot explain what has happened in the past half century. If anything, they would have cooled us since about 1980, during the period of most rapid warming.
And what about water vapour?
Water vapour is a major natural greenhouse gas. Always has been. It didn’t start recent warming, but it roughly doubles the warming caused directly by CO2. That is because if you add CO2 to the air and warm it, then evaporation increases, putting more water vapour into the air, causing further warming.
Didn’t those email leaks from the University of East Anglia prove that global warming scientists suppress opinions they don’t agree with?
Yes. Sometimes. To be fair, how many of us would come up smelling of roses if a selection of our most ill-advised emails were published on the internet? But even so, the emails showed a bunker mentality among some climate researchers, who have a hard time dealing with critics who work outside the "priesthood" of peer-reviewed research. But trying to shut out the critics, however disruptive they may be, is bad for science, which is (and should be) an adversarial process of open debate. Did the researchers succeed in suppressing opinions they disagreed with? No. Did the emails reveal a conspiracy to lie to us about the climate science? I have read most of them. I am a journalist. I love conspiracies. But the answer is no.
Isn’t the whole climate change scare a plan hatched by governments as a justification to hike up taxes?
Hardly. Governments have been dragged kicking and screaming to get serious about climate change. They’d just love it to go away.
Isn’t the suggestion of Lord Stern and others that we divert 1 per cent of the world’s GDP to prevent climate change a colossal misuse of money that could be better spent on improving human life – eradicating killer diseases such as malaria, for instance?
Stern says it will cost us a great deal more in the long run if we don’t tackle climate change. The trouble is that if climate change isn’t halted, it will carry on getting ever worse. Carbon dioxide hangs around in the atmosphere for centuries. So even if current emissions stayed as they are, we won’t stop at 1 or 2 degrees of warming, we will go on up to 4 and 6 and even 8 degrees. How hot can you handle? Ultimately, the only question is whether we stop it, or it stops us.