PERMIT me to reply to the letter "We must attend Rio summit", (NST, April 25) by Dr. Soon Ting Kueh.

As an atmospheric scientist, I want to correct his misconceptions and also explain why I support the US policy of not setting numerical or time limits on the emission of carbon dioxide, thereby allowing bureaucrats to control all energy use by citizens.

Like so many others, Dr Soon mixes up all kinds of environmental issues, some global, some regional and some strictly local.

Let me focus on global issues and point out that stratospheric ozone has nothing to do with greenhouse warming excerpt that they both occur in the Earth's atmosphere.

The temporary thinning of the ozone layer in the Antarctic stratosphere is a genuine phenomenon and a consequence of a uniquely low temperature there.

But there are no ozone "holes" in the Arctic or elsewhere, where temperatures are warmer.

Nor is there a general global decline of ozone as a result of human activities; natural variations are simply too large to establish such a trend.

While I don't oppose the eventual phase-out of CFC production, I see no need to panic and take such hasty actions as many Governments (including my own) are now doing by accelerating the phase-out. I am not sure that the rest of the world can adapt so quickly to the use of high-priced substitutes that haven't yet completed their safety tests.

With regard to greenhouse warming, the fears of a major climate change are purely theoretical speculation.

Even the 1990 UN report (by the Inter-governmental panel on climate change IPCC) states (on page 254) that the climate record doesn't prove any human-related warming, even though greenhouse gases have increased substantially as a result of fossil fuel burning, cattle raising and rice growing, especially since World War II.

We should see evidence of such warming in the climate record by now but we don't. The most accurate global data, taken by satellites, show no upward temperature trend.

Furthermore, the IPCC scientists who wrote the report, when surveyed, ex- pressed profound skepticism about the greenhouse theory that has been used to make the predictions about future warming.

Certainly, the majority of active climate scientists discount the fear of climate catastrophes.

Agriculturalists generally believe that the increased atmospheric concentrations of carbon dioxide should benefit the growing of crops. This is good news for most of the developing countries whose economies depend heavily on agriculture.

The trends of technology are encouraging. Countries are moving towards more efficient energy use; more are installing nuclear power plants that generate no carbon dioxide, and solar energy is becoming cheaper.

Many scientists therefore doubt that we will ever reach the condition of a doubling of atmospheric carbon dioxide.

In view of the shaky scientific base for greenhouse warming, countries should resist the UN-directed regulations that will be considered at the Earth summit in Rio in June.

Imposing energy controls will only damage national economies and cause great hardship, especially to the poor.

Economic development, which brings prosperity, requires greater energy use to build infrastructure and industry at least for several decades. Promoters of the Earth summit, which is supposed to advance both environment and development, do not seem to recognize this fact.