Curious case of taxes and greenhouse gas

By Associate Professor Allan Blackman

This article was orignally published in the Otago Daily Times on Monday 1 November 2004.

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Tax. It’s a word that’s never far from the news, and lately, certain alleged infelicities with respect to it by particular MPs have generated extensive coverage in the media.

While I’m sure that, given the chance, we’d all like to pay no tax at all, it is generally recognised that it is necessary for the good of the country.

An example of this is the Marsden Fund, a competitive fund administered by the Royal Society of New Zealand on behalf of the Government to support excellence in research.

Air and water . . . Henrik
Kjaergaard studies “hydrated
complexes” to learn more about
the atmosphere.

In early September, the results of the latest funding round were announced, and one of my colleagues in the Chemistry Department, Dr Henrik Kjaergaard, was successful in obtaining money ($707,250, including GST, over three years) to support his research into “The role of hydrated complexes in atmospheric reactions”.

Here’s a brief explanation of where your hard-earned tax dollars will go.

You’re all probably familiar with the terms “global warming” and “greenhouse gas”, and both terms are usually associated in the media with a single chemical species, namely carbon dioxide. While there does appear to be a correlation between the increasing amount of carbon dioxide in the atmosphere and gradual warming of the planet, there are many other species in the atmosphere that can potentially contribute to global warming.

If we are ever to understand the chemistry of the atmosphere, it is essential that some basic science concerning these species be undertaken, and this is where Henrik’s proposed research enters the picture.

If you’ve ever been to Rotorua, you’ll know that the place stinks (literally, not figuratively).

The smell is due to hydrogen sulfide, a gas with the chemical formula H2S, and just one of many naturally occurring small molecules that contain the element sulfur.

Of these, the most important are dimethyl sulfide, carbonyl sulfide and carbon disulfide, three molecules which are emitted in significant quantities from the oceans and which undergo reaction in the atmosphere to ultimately give sulfuric acid, a component of acid rain. In addition, sulfur-containing molecules are also produced by the combustion of fossil fuels, and these too eventually end up as sulfuric acid. However, not enough is known about how such atmospheric reactions occur, and this has led to a discrepancy between the calculated and observed amounts of sulfur in the atmosphere.

It is well known that small molecules in the atmosphere can collide with water molecules to form what are called “hydrated complexes”.

The simplest example of this is the water dimer, a species formed by collision of one water molecule with another.

Henrik and his co-workers were the first to show that this species behaves completely differently to individual water molecules and, as a result of this work, the presence of water dimer in the atmosphere was confirmed only last year.

It has been postulated that there may be many undiscovered hydrated complexes composed of a sulfur-containing molecule and a water molecule in the atmosphere, and that these may hold the link to understanding the atmospheric reactions of sulfur-containing molecules.

Henrik’s proposed research involves using sophisticated computer programs on minisupercomputers to calculate the structures of these unknown hydrated complexes, and to predict the way in which these complexes interact with infrared and visible light. This will allow these species, if present, to be detected in the atmosphere, and an estimation of their importance in the formation of acid rain constituents will be possible for the first time.

Henrik and his group are world leaders in this aspect of atmospheric chemistry, and this was recently recognized by Henrik’s promotion to the rank of Associate Professor.

I guess this means he gets to pay more tax now.