DESPITE THE nation's business-as-usual approach to energy consumption in recent months, the industrialized world is facing a potential oil shortage as serious as those in 1973 and 1979 that lead to gas lines and the doubling of oil prices.

Faced with a large number of uncertainties, particularly as we move from one administration to another, one must take great care not to overstate or understate the problem. Markets -- especially something as massive as the world oil market -- are often as sensitive to psychological stimuli as to underlying fundamentals.

Premature bleak news can set off a panic and produce results -- like the doubling of world oil prices in 1979 -- that are not justified by the actual facts. But given the need to inform public opinion and plan public policy, the total absence of alarms in the face of deteriorating market conditions might well mean that an unconditioned and shocked public suddenly faces a real crisis unprepared.

The balance between these two extremes is a delicate one. Nevertheless, striking it should be attempted. It is better to be prepared and then be pleasantly surprised than the other way around. Since any such market assessment could rapidly degenerate into a complicated debate over an endless stream of numbers, let's start with simple, general observations over which there is no disagreement:

When the Iran-Iraq war started in late September, the world lost approximately 4 million barrels per day of oil exports, or 16 percent of OPEC's then 25 million barrels per day of production. At the same time, world petroleum inventories were at a record high level -- some 500 million barrels in excess of normal requirements.

Adding in a 1-million-barrel-per-day production increase by various countries (led by Saudi Arabia) in response to the crisis, and making appropriate downward revisions in demand because of greater than expected conservation and a general economic downturn, the world entered the winter needing to draw approximately 2 million barrels per day of additional oil out of these record high inventories to balance supply and demand.

Historically, it is the relatively low-volume spot market -- individual, quick sales not made pursuant to long-term contracts -- where the price first rises, thereby foreshadowing a later official OPEC contract price increase. Although spot crude and product prices have risen modestly since the war started, the world has thus far avoided the kind of panic, giant price increases and shortages that plagued us in 1973/74 and 1979. In essence we have been living off our high inventories.

To date, our borrowing from reserves has caused us to use about half of the 500-million barrel inventory surplus that existed at the beginning of the war. Without some meaningful additional production from Iran and/or Iraq, the entire 500-million-barrel inventory cushion could be gone some time this spring, leaving worldwide petroleum inventories only slightly above the level that existed in the spring of 1979 when the U.S. experienced its most severe gas lines. If our current inventory surplus is exhausted by spring and there are still no prospects for additional production, normal summer restocking will not take place, leading to serious supply and price difficulties next fall.

As a practical matter, it is unlikely that the oil industry would allow petroleum inventories to sink to spring 1979 levels in view of the marked changes which have occurred since that time. The major multinational oil companies control less of the oil in world trade. There are fore more individual traders -- independents, who relied on the majors have now become direct purchasers. Awareness of the political instability and supply undependability of the Gulf has also increased. All of these developments mean that today's minimum stock levels for individual companies should be higher than in 1979.

But there are individual companies and countries whose specific stock situations are worse than the average. Without extensive help from other countries or companies through the consuming nations' energy organization, -- the International Energy Agency -- these countries will have to resort eventually to major new purchases on the spot market, triggering a wave of buying that could rapidly escalate prices. This could occur well before total inventories are drawn down to minimum levels.

So, setting aside the implications of a continued inventory drain for next fall and winter, under current conditions spot prices and volumes could begin rising sharply before the latter part of spring if:

There is no additional production from Iran, Iraq or somewhere else and/or;

No practical way is found of providing relief to specific countries and companies who now find themselves in poor stock positions.

The news is mixed about the possibility of a major restoration of production in Iraq during the first quarter of 1981. Iraq was exporting a little over three million barrels a day of oil prior to the war, about two million barrels a day through their southern Persian Gulf terminals and one million barrels a day through northern pipelines leading from their major producing fields to the Mediterranean.

The bad news is that the Persian Gulf facilities appear to be seriously damaged and will take several months to repair or replace even partially, and probably a year to rebuild completely. Since the fighting currently shows no sign of stopping, it could be well into 1981 before these repairs are complete. s

The good news is that the relatively undamaged northern pipelines leading to the Mediterranean through Syria and Turkey have a total capacity available to Iraq of slightly more than 1 million barrels a day, and with several months of repair work could attain flows of as much as 2 million barrels a day. In late November and early December, some of the sections of these lines were reopened for the first time since the way began and flows reached as much as 900,000 barrels per day before being shut down the second week in December because of unspecified damage. As best as can be determined from contacts in the industry, some portion of the lines were again reopened in late December, and are currently running at several hundred thousand barrels per day.

Since the Iraqi Persian Gulf facilities cannot be counted on for a long time, the greatest single variable is whether Iraq can maintain reliable, significant flows through its Mediterranean pipelines. The record to date is not encouraging. As long as the war continues, interruptions of varying durations can be expected. An optimistic average for the first quarter might be from half to 1 million barrels a day. While immediate peace could perhaps bring 2 million barrels a day by the end of the quarter, something closer to zero for most of a quarter during which the war continues is also possible.

Iran's major export facilities (as opposed to refineries) have not suffered as much damage as Iraq's. During the early part of the war, however, exports dropped from the already reduced prewar level of under 1 million barrel per day to just several hundred thousand barrels per day, primarily due to the dangers of operating in the Gulf during the early days of heavy bombing. According to press and industry reports, Iranian exports have climbed back close to prewar levels in recent days. Without major new war offenses, Iran might be able to attain as much as 1.5 million barrels per day of exports before the end of the first quarter. However, with renewed fighting in the early spring, exports could drop back to just several hundred thousand barrels per day.

Under the best conditions, it would therefore be possible to begin making up the 2 million barrels or so per day worldwide shortfall at some point in the first quarter from Iran and Iraq. The overall average from these two countries, however, is more likely to run at the level of the first several weeks of the first quarter, or about 1 million barrel a day. This shortfall is substantial enough to delay the theoretical exhaustion of the inventory cushion from spring until later in the summer. The possibility that Iran/Iraq production increases could be offset by a reduction in the temporary emergency increases of other producers such as Saudi Arabia also must be considered. If the conflict broadens or the fighting increases, and Iran and Iraq together cannot maintain 1 million barrels per day of production, this theoretical reckoning day accordingly moves closer.

Superimposed on these theoretical assessments is a psychological climate often governed by the weakest link in a chain of countries and oil companies whose supply situations are at the lowest end of the curve. Turkey and Portugal -- two of our 20 allies in the IEA -- are moving dangerously close to the bottom of their reserves. Other IEA countries are waiting to see if U.S. companies continue their spot market restraint in view of declining inventories. A fair number of independents and even some multi-national majors are now approaching their minimum inventory requirements. Well before the hypothetical minimum average stock level is reached, some country or company could find it necessary to go to the spot market for substantial replacement volumes, and the panic could be on.

For all its shortcomings -- and there are many -- the avoidance of a panic to date is in lare part due to the coordinative efforts of the IEA in urging countries and companies to make maximum use of the massive stock levels at the beginning of the war. On Oct. 1, the IEA urged all member countries to meet the shortage by drawing on existing stocks until the end of the year and to refrain from spot market purchases. In early December, at an IEA ministerial meeting in Paris chaired by then-U.S. Energy Secretary Charles Duncan, the IEA strengthened this action by urging stockdraws or demand restraint measures in the first quarter, sufficient to reduce by 10 percent total IEA demand for oil on the world market, as well as continued avoidance of spot purchases.

To date, the approach has worked. The market has stayed relatively calm. But how much longer can it last? As in most international accords, participation is untimately voluntary. Perhaps most troubling, the centerpiece of this successful IEA strategy is a rapidly depleting asset -- surplus inventories that in just 18 weeks are already about one-half gone. Will companies worried about their own plans to rebuild stocks help out Turkey or other severely affected countries at competitive prices? Will companies with higher stocks voluntarily help companies with lower stocks in the face of U.S. antitrust laws and the perception that eventually all companies will have to resort to the spot market?

If calm is to be maintained in this increasingly tense situation, it is clear that strong leadership from a U.S. government with a realistic understanding of the situation will be esential. The moment our international partners sense that the United States may be content to go it alone in 1981, the delicate house of cards erected by the IEA will collapse and the cutthroat bidding for limited world oil supplies that saw an unnecessary doubling of the oil price in 1979 could be repeated. The economic devastation associated with this route is almost unthinkable.

The first step then, is a realistic assessment of the potential problem. If everything that can possibly go right does -- and it would be a first in oil market history -- we might squeak through 1981 with no major market disruptions, thanks to a rapid peace settlement and quick restoration of maximum exports through the Mediterranean pipelines together with Iranian exports in excess of prewar levels. Based on everything we know today, this is wishful thinking.

The most likely case is that traditional restocking this summer will be difficult, raising the very real possibility of substantial price increases and actual shortfalls this coming fall and winter.

Whether we like it or not, the energy consuming free world will be looking to the United States to set the tone in the delicate days and weeks ahead. In a very real sense it is a question of whether we sit back and let it happen to us again, or whether -- in the face of a fairly well defined danger -- we try to get in front of the next major oil shock and in so doing help reduce its impact.

If we accept our position of world leadership on this matter, there are tools at our disposal for appropriate reductions in demand and increases in supply. Speeded -up decontrol fo crude oil prices is one such action that has already been taken. An import fee, a gasoline tax, fuel switching, increased use of natural gas (including gas imports) and new conservation incentives are just a few of other initiatives that could help the United States reduce the worldwide shortfall in 1981, while enhancing our effectiveness and credibility in urging our allies to do the same. The more we act together, the greater are our chances for success.

These and other appropriate measures should be put in a state of readiness while we closely monitor the critical signs of this potential crisis (inventory levels, spot market activity, demand trends, the war) and keep the public informed and educated about the situation as it unfolds. The American people will be ready to respond when that response is needed if they are made aware of the possible dangers as they develop. Government must find that middle ground between overstating and understating the problem, so that we can break the boom and bust psychology of recent years that has either put us in the middle of a full-fledged energy emergency (May and June of 1979) or general energy complacency (today).

If recent history teaches us anything, it is that our energy future always seems worse than what we predicted, and our ability to deal with each new situation less satisfactory than we might have hoped. Unless we face up to reality now, we may soon find ourselves again in the midst of an unnecessarily severe energy crisis, the third in six years.