(Response to "Efforts to Stop the Climate From Changing Are Sure to Fail," @Guelph, Sept 13)

Titanic in the fog off the coast of Labrador:

Physicist: Captain, there's a large iceberg ahead.

Economist: I dispute this. Your binoculars are dirty, visibility is poor, and I don't see anything.

Physicist: OK, let's be specific: I'm 90-per-cent sure there's something big out there and 50-per-cent sure it's an iceberg.

Economist: Since you can't prove it, we must continue straight ahead and not disrupt our schedule.

Physicist: Let's take a detour to be safe.

Economist: That would be too expensive. Again, you have failed to prove there's an iceberg out there, so we must continue full speed ahead.

Physicist: Sir, these are arctic waters, so an iceberg would not be unexpected.

Economist: I have this weather report from Panama claiming there are no icebergs off the coast of Labrador.

Physicist: Sir, that report is 10 years old. Icebergs have been sighted in the region for many years, according to the shipping charts.

Economist: Even if there were icebergs around here, a small detour would probably lead us into another iceberg with the added cost of an expensive delay. As it is, we are running late. Captain, you must order an increase in speed.

Physicist: Sir, as we come closer, the object ahead indeed looks more and more like a massive iceberg.

Economist: This ship is tough. And the relative importance of icebergs in causing damage to ships is highly disputed. Even if there were an iceberg dead ahead, we could just plow through it.

Physicist: Sir, if we start a small course change now, it will cause less delay than if we wait until we're closer.

Economist: We can't afford any delays. Maybe this physicist can afford to arrive later, but it would be unfair to our passengers and they won't stand for it. In fact, the faster we go, the better chance we have of plowing through any obstacles. Captain, I must insist we increase speed to the fullest possible.

Who gets the last word?

Climate is always changing. But the rate at which we are imposing long-term changes on components of the radiative energy balance of the Earth's climate system has no geological analogue back to at least the K-T boundary (when dinosaurs disappeared). Prof. Ross McKitrick seems happy to ignore this and is more comfortable replacing uncertain science with sloppy science using an outdated citation of correlations (which, without physical links, do not imply causation, at least in the physical sciences). He also ignores geological evidence that variations in atmospheric CO2 have driven past climate change (e.g., Shackleton, Science, Sept 15, 2000).

When dealing with complex non-linear systems with layers of feedbacks such as the climate system, certainty is often unattainable. But when faced with uncertainty and risk, most of us will take some precautions. Those who ignore the possible/probable effects of increasing greenhouse gases decry scientific uncertainty, but appear to claim enough certainty in their own positions that precautionary reductions in greenhouse gas emissions aren't warranted.

Economists are happy to impose large-scale socioeconomic dislocations in the name of the free market. They then complain that changes to the economic order will most hurt the poor and conveniently ignore that it's the current economic order that is most hurting the poor. Prof. McKitrick's bottom line appears to be that both the biosphere (which includes us) and the climate system must adapt to the current economic/energy system. I guess the free market has replaced God.

Lev Tarasoff, Atmospheric Research Group, University of Toronto

On Oct. 1 at about 2 a.m., two U of G students were assaulted and beaten to the ground by a group of eight to 10 assailants. This vicious attack took place on Gordon Street across from the Macdonald Stewart Art Centre. One of the individuals received serious injuries and was transported to Guelph General Hospital. He underwent surgery later that day to repair a compound fracture in his jaw.

This letter goes out as a plea to any individuals who witnessed this assault to please come forward and aid the police in apprehending those who caused this physical and emotional pain.

Anyone who was a witness is asked to contact Const. Hoyer at Guelph City Police, 824-1212, Ext. 7247.

Many thanks in advance to those who come forward for their honesty, courage and assistance. It will be much appreciated by his family and all his friends.

David Thwaits, Undergraduate student

It is praiseworthy that one with such excellent accomplishments as Prof. Maureen Mancuso be named associate vice-president (academic). It testifies to the far-sightedness of the present administration. I wish to add my heartfelt congratulations.

Hendrik Kahar, Undergraduate student