Last Gasp

Boris was still frowning. 'It's possible that the man who attacked Cheryl was with your State Department?'

Theo nodded.

'He would make the threat so openly?'

'Sure, that's nothing,' Cheryl said, making herself comfortable on the foot of the bed nearest the window. 'I'm surprised he didn't shoot me in the back and leave a note pinned to my panties. Threats, coercion, blackmail, frame-ups, these people are experts.' She gave a sardonic smile. 'America is a democracy, don't forget. You're free to threaten anybody you want to.'

Chase was mystified by all this. He said, 'That paper of yours must be pure dynamite, Dr. Detrick. What were you intending to speak about?'

'Its title is 'Back to the Precambrian,' Dr. Chase,' and when he saw Chase's blank expression, went on, ' 'Precambrian' is the term I have given to describe the reversion of the earth's atmosphere to what it was two billion years ago when the constituents were principally a highly corrosive mixture of hydrogen, ammonia, and methane. But no oxygen,' he added significantly.

'You believe the earth is reverting to that state?'

'Unfortunately, I do,' Theo said gravely. 'I wish I could draw other conclusions from the work I've done, but . . .' He shook his head sadly.

'Your work on diatoms, you mean?'

'On the phytoplankton species in general. In the equatorial Pacific, which is normally one of the most productive regions of the ocean, all classes of phytoplankton are in drastic decline. As the oceans provide most of the oxygen requirement there must inevitably come a time when ths level of oxygen produced is reduced. Possibly within the next twenty to fifty years. Within a hundred years all the free oxygen at present circulating in the atmosphere will either have been consumed or will be locked up in various oxidation compounds, such as rocks, decaying matter, and so on. When that happens we shall be left with an atmosphere similar in composition to what it was in the Precam-brian period, two billion years ago.' He gave a wan smile. 'Man is a most arrogant species, Dr. Chase. He forgets that for millions of years this was a sterile planet with a poisonous atmosphere. It was only with the liberation of oxygen into the air that our form of organic life was able to evolve--but the biosphere doesn't owe us a living. We take it as a God-given right that oxygen is there for us to breathe, when in fact it is an accident, a biological quirk, so to speak, of nature.'

Chase said diffidently, 'I don't question the validity of your research, Dr. Detrick, but frankly I find your prognosis hard to take. I don't know the actual figure, but the amount of oxygen in the atmosphere is immense--' '1,140,000,000,000,000 tons,' Theo said.

'Surely that's more than enough to meet our needs for the foreseeable--indeed, the unforeseeable--future? I assume that phytoplankton growth won't cease altogether, so presumably the oxygen level will continue to be 'topped up.' And there are the green plants on land that supply a sizable proportion of oxygen, at least thirty percent.'

Theo sipped his drink, sunk for a moment in thought. 'I take your point, Dr. Chase,' he said finally. 'You are absolutely right to make it. But in considering the oxygen yield of the biosphere and whether it is sufficient for our long-term needs, there are two sides to the equation. Let us call them 'profit and loss' and draw up a global balance sheet.

'On the profit side we have an abundance of green plants, in the oceans and on land, which daily perform the miracle of photosynthesis, absorbing the rays of the sun and through the chlorophyll in bacteria producing energy that is used to break down water molecules into their component parts. The hydrogen thus released is combined with carbon to supply sugar for the plant's own needs, while the oxygen is given off as a waste product.' Theo held up his fist, which shook slightly. This process, far more complex than that taking place in a petrochemical plant-- and, what's more, happening inside a group of cells less than one billionth of an inch in diameter--is the unique factor that allows animal life to exist on this planet. Without it'--the fist flicked open to become a knife blade that sliced the air--'nothing!'

'I think it's safe to assume that Dr. Chase is familiar with the miracle of photosynthesis,' Cheryl said mildly.

'Yes, yes, please forgive me.' Theo spread his hands in apology. 'You must understand that this and little else has occupied my thoughts for a long time.' He eased back in the chair, his profile etched against the lamplight. 'That, as I say, is the profit side of the equation. On the loss side we have the consumption of oxygen: every form of life that respirates, including man, and every kind of combustion process-- power plants, factory furnaces, automobiles, aircraft, domestic boilers --everything in fact that burns fossil fuels.

'Now, it has been estimated, based on the most reliable sources available, that every year we consume between ten and fifteen percent of the free oxygen in the atmosphere. Until today that annual deficit has, as you point out, been 'topped up' by the photosynthetic activity of green plants.

'However, we must now take into account several new factors. First, the increase in world population, which by the year 2000 will be approximately six and a half billion. If we progress as we have been doing, this will mean more of everything--power plants, factories, cars, aircraft--all of which will demand more and more oxygen. Each year that ten to fifteen percent deficit will grow larger. Maybe that wouldn't matter too much if the production of oxygen continued at its present rate; but when we look closely at the balance sheet we find that the profit side is getting more and more into the red.

'As well as the declining phytoplankton we're also losing the world's major forests. Deciduous forests have an oxygen-producing capacity one thousand times greater than the average land surface, and in the United States alone we cover an area the size of Rhode Island--five thousand square miles--with new roads and buildings every year.

'We all know about the great forests in South America, Southeast Asia, Borneo, New Zealand. They're being destroyed at an alarming rate, but even more disastrously they're being burned--which at a stroke turns that item on our balance sheet from profit to loss. Instead of being net producers of oxygen, the forests have become net consumers. ' Theo looked at Chase, a tired smile plucking at the corner of his mouth. 'I could go on, but I think you see my point.'

'Which is,' Boris put in somberly, 'less profit, more loss. The equation does not balance. We consume more of what isn't there no longer.'

The Russian, with his quaint English, had come up with a clumsy yet telling description, thought Chase. We consume more of what isn't there no longer.

'Must the earth revert to its primordial atmosphere?' he wanted to know. 'Isn't there another possibility, another direction it might take?'

Theo was prepared to admit he might be wrong, but added a killing rider: 'I've tried to make the equation balance and found it impossible; believe me, Dr. Chase, I have tried.'

For all that man had done to the environment, the planet's complex web of self-regulating mechanisms had always in the past managed to compensate for his use and abuse of natural resources. But that, as Chase now realized, was begging the question. Detrick wasn't talking about what had happened in the past but of the earth's ability to cope in the future--with all the additional burdens man was imposing on it year by year.

Boris drank some beer and said, 'You were perfectly correct, Dr. Chase, to speak of the hugeness of our planet.' He smothered a belch and Chase raised his hand to hide a smile. Boris stared accusingly at his glass and went on, 'In one year the volume of water recycled by evaporation is three hundred and eighty thousand cubic kilometers. In one year over one hundred thousand million tons of carbon dioxide are absorbed in the oceans and nearly two hundred thousand million tons are converted into plant material by photosynthesis. To recycle a single molecule of water from the ocean, via the atmosphere, through photosynthesis, and return it to water by animal respiration, takes two million years. The resources are enormous, yes, the processes incredibly complex, yes, but I am always reminded of something Buckminster Fuller once said. You remember, Theo?'

After a moment Theo nodded and said, 'The steel ball.'

The Russian smiled and swiveled his shorn head toward Chase. 'Fuller said that to get a true picture of the depth of the oceans, think of a steel ball the height of a man. Breathe on the surface of the steel ball and your condensed breath represents the average depth of the oceans. You see? While it is true that man lives on a planet that is vast in comparison with himself, he actually survives thanks to a thin layer of