Letters

IN RESPONSE to the letters about climate change, I think the sceptics are not seeing the big picture. Whether you believe that climate change is happening or not, it's time we took responsibility for our impact on the environment. Don't you think that we have caused enough damage already? One of the implications of climate change is that we each have to reduce our carbon emissions and recycle. After more than three centuries of industrialisation, it's time for us to take responsibility for our actions. We are finally recognising the consequences of our actions on the environment. And if you still do not believe that we need to take action, well, I have two words for you: Grow up.

Valentina Tan

Responsible Individual and economics student of Monash University, Malvern East

Evaluated computer models just invalid

YOUR correspondent David Jones (BusinessDay, 17/7) claims that there are many studies that "validate" computer models of the climate.

This is just not true. I have been an "expert reviewer" to the Intergovernmental Panel on Climate Change (IPCC) for the past 18 years. The IPCC's first report in 1990 actually had a chapter "Validation of Climate Models" and the same title appeared in the first draft of the next report.

At the time I said that since no climate model had ever been validated the term was wrong. The IPCC agreed. It changed the word "validated" to "evaluated" no less than 50 times in the next draft, eliminated the word "validated" from every one of the subsequent reports and used "evaluated" instead.

The term "validated" is used by computer engineers to describe the procedures that have to be carried out before a computer model can be considered suitable for forecasting. The procedure must include successful prediction, to a satisfactory level of accuracy, for all the future circumstances for which the model is intended.

No computer model has been subjected to such a discipline, and the IPCC reports have never included a discussion of the procedures that are needed before a computer climate model could be considered a reliable means of predicting future climate.

As a result, the IPCC never "predicts" the future climate. It only "projects" it. A "projection" is a result of the particular assumptions made in a particular model, but it cannot be taken seriously unless it is actually successful. So far, no such model has ever been successful in predicting any future climate

Vincent Gray, Crofton Downs

Inflated wealth not substantial

I FOUND part one of The Sum of Us very interesting, but I would take issue with the assertion that "average household wealth is substantially inflated by a relative few". Statistically, the median must be less than the average. Having the median at 60% of the average is much higher than I would have expected. It indicates a society where most people can expect to increase their wealth as they go through life.

Yes, average family wealth is inflated by the wealthy few, but this difference cannot be termed substantial.

Cliff Strahan, Greensborough

We did not assess

Hegarty payout: Mercer

WE AGREE with Michael West that the whole point of performance pay is performance, not retirement (BusinessDay, 15/7). We would point out that Mercer was not involved in advising Oxiana on Owen Hegarty's retirement package.

The work undertaken by Mercer with regard to Oxiana's executive pay program has been to provide actuarial evaluations of the options in its long-term incentive plan.

We were not asked to, nor did we express, a view on the reasonableness or otherwise of the managing director's retirement package. We were simply asked to provide a present value of the unvested options, in accordance with accepted accounting standards.

West is on the mark in noting that: "This year, in the first bear market for many years, it is crunch time for executive pay." The debate about executive remuneration should be alive and one can only hope that future contributions are more accurately informed.

Yolande Foord, Business leader, executive remuneration, Mercer