Do you think those who have reservations about whether man is creating global warming should lose their jobs and be denied the right to present their views?

Over the last few months, there has been a concerted effort to silence those who have doubts about global warming and man's effect on the climate. The OregonState climatologist was fired for disagreeing with the "conventional wisdom." A meteorologist with the weather channel demanded that dissenting views not be broadcast. CNN, in particular, has treated skeptics with great disdain.

As an economist, I do not claim to know for certain who is right and who is wrong in this debate, but I do know that attempts to shut down debate are both wrong and dangerous. When I was a student, Keynesian economics was the "consensus," and those few who disagreed, like Milton Friedman and F.A. Hayek, were ridiculed by the economic establishment, and students in many universities were not even exposed to their views. By the late 1970s, it was apparent to those who cared to look at the data and the world around them that Keynesian economics had all been wrong and Friedman and Hayek had been right. Once Margaret Thatcher, Ronald Reagan and other government leaders adopted the Friedman/Hayek model, their economies and also the world economy, entered the longest and highest rate of growth ever. History is filled with those who dissented against the conventional wisdom but were proved correct, such as Copernicus, Galileo, Albert Einstein and many others.

The doomsayers in the media and political classes were all atwitter last month when the most recent U.N. Intergovernmental Panel on Climate Change (IPCC) report was released, saying humans were partly to blame for global warming -- so I decided to read the report.

Let's do a mind game. The authors of the report predict average temperature will increase between 3.2 and 7.8 degrees Fahrenheit over the next century, and that sea levels will rise between 7 and 23 inches. Assume, for the moment, that mankind can do nothing about this projected climate change. Given that information, how would you change your behavior? If you are like most people, you would do nothing but enjoy the few extra days of summer and swimming. If you were going to build a house on the sea, you might build it a couple of feet higher than the existing codes require -- no big deal. Unless you enjoy shoveling the snow, having a little less of if to contend with each winter probably would bring more pleasure than pain.

Now, let us assume mankind might be able to slowly reduce global warming by drastically reducing carbon emissions. This can be done by increasing the cost of power and fuel. How much would you be willing to pay to make these changes for something you would barely notice over your lifetime? Would you be willing to take on these extra costs, knowing they would accomplish very little if the citizens of the rest of planet did not do the same?

What do this and other reports about climate change tell us? A majority agrees the most notable temperature increases will be in upper Canada and Siberia, and the moisture these areas receive will increase -- which means much better and longer growing seasons in these areas. These favorable developments will be partially offset by longer droughts in some localities. But given that both these positive and negative changes will occur slowly over a century, humankind will have plenty of time to adapt, and on balance it will be easier and less costly to produce food. If you are a skier, your season will be shortened, but if you play baseball, football, golf or swim, your season will be longer.

However, if the politicians on the left operate true to course, they will propose even more costly regulations and higher taxes, without any offsetting tax reduction. This will unnecessarily make the poor poorer and reduce job creation. The brains of many on the left (and some on the right) seem unable to understand second-order effects of policies and actions, which tends to make them overstate problems and come up with solutions that do more harm than good.

Vaclav Klaus, who is both a distinguished economist and president of the Czech Republic, criticized the new U.N. report on global warming, saying it was a political document, "without scientific basis." He also said, "a sane person can't conclude that we are ruining the planet" as Al Gore has said, given that the planet is now far more user friendly for humans than it has ever been in the past.

It is worth remembering that, as recently as the 1970s, a consensus held we were in a period of global cooling and might face a new ice age. Those who seek to shut down the debate are only revealing their ignorance of history and disdain for liberty.

Richard W. Rahn is a director and board member of several economic policy organizations, including the EuropeanCenter for Economic Growth.