China's export restrictions on resources for semiconductors

The Financial Times reported last week (paywalled):

Chinese export controls on crucial semiconductor materials are hitting supply chains and stoking fears of shortfalls in western production of advanced chips and military optical hardware.

Beijing’s curbs on shipments of germanium and gallium, which are used for semiconductor applications and military and communications equipment components, have led to an almost twofold increase in the minerals’ prices in Europe over the past year.

China introduced the restrictions, which it says safeguard its “national security and interests”, last year in response to US-led controls on sales of advanced chips and chipmaking equipment.

The FT article focuses on the effect of the export controls on Europe. However, I want to look at the effect of the export controls (an export quota) on the prices of the resources (gallium and germanium) in China. However, let's start by considering why China is an exporter, and the gains from trade for China. This is demonstrated in the diagram below. China has a comparative advantage producing these resources. That means that China can produce gallium (or germanium) at a lower opportunity cost than other countries. On a supply-and-demand diagram like the one below, it means that the domestic market equilibrium price of gallium (PD) would be below the price of gallium on the world market (PW). Because the domestic price is lower than the world price, if China is open to trade there are opportunities for traders to buy gallium in the domestic market (at the price PD), and sell it on the world market (at the price PW) and make a profit (or maybe the suppliers themselves sell directly to the world market for the price PW). In other words, there are incentives to export gallium. The domestic consumers would end up having to pay the price PW for gallium as well, since they would be competing with the world price (and who would sell at the lower price PD when they could sell on the world market for PW instead?). At this higher price, the domestic consumers choose to purchase Qd0 gallium, while the domestic suppliers sell Qs0 gallium (assuming that the world market could absorb any quantity of gallium that was produced). The difference (Qs0 - Qd0) is the quantity of gallium that is exported. Essentially the demand curve with exports follows the red line in the diagram.

In terms of economic welfare, if there was no international trade in gallium, the market would operate at the domestic equilibrium, with price PD and quantity Q0. Consumer surplus (the gains to domestic gallium consumers) would be the area AEPD, the producer surplus (the gains to domestic gallium producers) would be the area PDEF, and total welfare (the sum of consumer surplus and producer surplus, or the gains to society overall) would be the area AEF. With trade, the consumer surplus decreases to ABPW, the producer surplus increases to PWCF, and total welfare increases to ABCF. Since total welfare is larger (by the area BCE), this represents the gains from trade.

Now consider what would happen if there is an export quota limiting the quantity of gallium exports below (Qs0 - Qd0). This is shown in the diagram below. Let's say that the quantity of exports is reduced to the amount between B and G on the diagram (about half the amount of exports that were previously occurring). Now consider what happens to the demand curve (including exports). The upper part represents the domestic consumers with high willingness-to-pay for gallium. Then there is a limited quantity of exports that are allowed under the export quota, at the world price PW. After that, there are still profit opportunities for domestic suppliers (that is, there are still some domestic consumers who are willing to pay more than what it costs the suppliers to produce gallium). So, the demand curve (including the export quota) pivots at the point G, and follows a parallel path to the original demand curve (i.e. the demand curve including exports follows the red line in the diagram). The domestic price is the price where supply is equal to demand (P1). The domestic consumers choose to purchase Qd1 gallium at the price P1, while the domestic suppliers sell Qs1 gallium at that price. The difference (Qs1 - Qd1) is the quantity of exports of gallium.

Now consider the areas of economic welfare. The consumer surplus is larger than it was without the restricted exports (it is now the area AJP1), the producer surplus is smaller than it was without the restricted exports (it is now the area P1HF). There is a new area of welfare KLHJ, which is the profit that exporters of gallium would receive from exporting, because they can purchase the gallium at the price P1 domestically, and then sell it to the world market at the price PW. This area KLHJ is the licence-holder surplus. Total welfare is smaller than without the restricted exports (it is now the area AJHF+KLHJ). There is a deadweight loss (a loss of total welfare arising from the restricted exports) equal to the area [BKJ + LCH] - these areas were part of total welfare with trade and no restricted exports, but have now been lost. The reduction in exports makes domestic gallium suppliers worse off, as well as society overall (in terms of economic welfare in total). However, domestic gallium consumers benefit in terms of higher consumer surplus, and the export licence holders are a new group that gains from these restrictions.

Now, the model we used above relies on an assumption that Chinese decisions about gallium (or germanium) exports do not affect the world price. In fact, because China produces 98 percent of the world's gallium, and 60 percent of the world's germanium (according to the FT article), this is unlikely to be true. When China restricts exports through the quota, the world price will increase. That has the effect of increasing the surplus for the export licence holders, but otherwise doesn't affect domestic consumers or producers. However, it will make international consumers worse off, since they would now have to pay a higher price for gallium. And that's what the FT article shows. However, now we know that it isn't just the global consumers of these resources who are worse off, but Chinese mining companies, and Chinese society generally, as well.

The effect of timber export restrictions on the domestic market for timber

The housing crisis is causing the government to search frantically for solutions. As the New Zealand Herald reported last week:

The Government was warned its efforts to tackle New Zealand's housing affordability issues could be hampered by wood shortages.

The issue has become so significant, Building and Construction Minister Poto Williams is considering limiting timber exports to ensure there is enough in the country.

What happens if the government limits timber exports, by implementing an export quota? Before we can answer that question, we need to consider the effect of exports on the domestic market, without any restrictions on exports. That situation is shown in the diagram below. New Zealand is an exporting country, which means that New Zealand has a comparative advantage producing timber. That means that New Zealand can produce timber at a lower opportunity cost than other countries. On a supply-and-demand diagram like the one below, it means that the domestic market equilibrium price of timber (PD) would be below the price of timber on the world market (PW). Because the domestic price is lower than the world price, if New Zealand is open to trade there are opportunities for traders to buy timber in the domestic market (at the price PD), and sell it on the world market (at the price PW) and make a profit (or maybe the suppliers themselves sell directly to the world market for the price PW). In other words, there are incentives to export timber. The domestic consumers would end up having to pay the price PW for timber as well, since they would be competing with the world price (and who would sell at the lower price PD when they could sell on the world market for PW instead?). At this higher price, the domestic consumers choose to purchase Qd0 timber, while the domestic suppliers sell Qs0 timber (assuming that the world market could absorb any quantity of timber that was produced). The difference (Qs0 - Qd0) is the quantity of timber that is exported. Essentially the demand curve with exports follows the red line in the diagram.

In terms of economic welfare, if there was no international trade in timber, the market would operate at the domestic equilibrium, with price PD and quantity Q0. Consumer surplus (the gains to domestic timber consumers) would be the area AEPD, the producer surplus (the gains to domestic timber producers) would be the area PDEF, and total welfare (the sum of consumer surplus and producer surplus, or the gains to society overall) would be the area AEF. With trade, the consumer surplus decreases to ABPW, the producer surplus increases to PWCF, and total welfare increases to ABCF. Since total welfare is larger (by the area BCE), this represents the gains from trade.

Now consider what would happen if there is an export quota limiting the quantity of timber exports below (Qs0 - Qd0). This is shown in the diagram below. Let's say that the quantity of exports is reduced to the amount between B and G on the diagram (about half the amount of exports that were previously occurring). Now consider what happens to the demand curve (including exports). The upper part represents the domestic consumers with high willingness-to-pay for timber. Then there is a limited quantity of exports that are allowed under the export quota, at the world price PW. After that, there are still profit opportunities for domestic suppliers (that is, there are still some domestic consumers who are willing to pay more than what it costs the suppliers to produce timber). So, the demand curve (including the export quota) pivots at the point G, and follows a parallel path to the original demand curve (i.e. the demand curve including exports follows the red line in the diagram). The domestic price is the price where supply is equal to demand (P1). The domestic consumers choose to purchase Qd1 timber at the price P1, while the domestic suppliers sell Qs1 timber at that price. The difference (Qs1 - Qd1) is the quantity of exports. Notice that the price of timber that timber consumers pay has fallen, and more timber is purchased domestically - we'll come back to those points shortly.

Now consider the areas of economic welfare. The consumer surplus is larger than it was without the restricted exports (it is now the area AJP1), the producer surplus is smaller than it was without the restricted exports (it is now the area P1HF plus the area KLHJ. The first area (P1HF) is producer surplus as if the farmers sold all of their products to the domestic market, while the second area (KLHJ) is the extra profits the suppliers get from selling the quota of exports. Total welfare is smaller than without the restricted exports (it is now the area AJHF+KLHJ). There is a deadweight loss (a loss of total welfare arising from the restricted exports) equal to the area [BKJ + LCH] - these areas were part of total welfare with trade and no restricted exports, but have now been lost. The reduction in exports makes timber suppliers worse off, as well as society overall (in terms of economic welfare in total). However, timber consumers benefit in terms of higher consumer surplus.

Now consider the goals of the export quota. If the government is worried that domestic timber prices are too high, the export quota will lower the price (from PW to P1). If the government is worried that not enough timber is available and sold locally, the export quota will increase that quantity (from Qd0 to Qd1). It sounds like the export quota will have all the effects that the government might want. However, there is no free lunch here. Domestic timber producers are made worse off, and by more than the amount that domestic timber consumers gain (we know this because total welfare overall declines).

The negative impact on domestic timber producers is going to create a couple of negative incentives. First, at the margin it will dissuade timber growers from planting forests, because the return on investment will be lower (as timber prices are lower). Of course, that's not going to impact the market until 20-25 years into the future, so the current government might not care. Second, timber growers might prefer to leave their forests uncut, hoping that the export quota is lifted after the next change in government. If prices are low now, but there is an anticipated higher price in the future, then holding back supply might be a good strategy for some timber growers. That will have the opposite effect from what the government intends, because a reduced domestic supply of timber raises the domestic price, and decreases the quantity of domestic timber sold. This effect seems very likely to me.

The government needs to tread carefully, lest they create incentives that actually make the problem worse in the long run. Policy alternatives that encourage timber supply, rather than discouraging it, are likely to be more effective overall.

Reduced exports due to border restrictions and the domestic market for strawberries

Last week, my ECONS102 class covered international trade, including the effects of trade restrictions on economic welfare. Usually, the examples I use involve the government interfering in the market, through the use of quotas or tariffs, and those trade policies invariably lead to a loss of economic welfare (a deadweight loss). However, sometimes other things get in the way of international trade, such as this recent example from HortNews:

Strawberry prices fell 43% in November 2020 as Covid-19 border restrictions reduced exports, Stats NZ said.

Consumer prices manager Katrina Dewbery says that fewer exports have meant there is more supply available for domestic consumption.

Prices averaged $3.45/250g punnet in November, down from $6.04 in October.

“Prices are lower than we typically see for a November month with December generally being when they are cheapest. Some people may be seeing even cheaper prices during the first half of December,” Dewbery said.

There was no government intervention here, but a lack of capacity to export strawberries due to the COVID-19 border restrictions reduced the quantity that could be exported. We could interpret that as being similar to an export quota on strawberries (where the quantity of exports was restricted to less than it would have been with open borders), so let's look at the effect on the market for strawberries.

First, consider the case without any border restrictions. This is shown in the diagram below. New Zealand is an exporting country, which means that New Zealand has a comparative advantage producing strawberries. That means that New Zealand can produce strawberries at a lower opportunity cost than other countries. On a supply-and-demand diagram like the one below, it means that the domestic market equilibrium price of strawberries (PD) would be below the price of strawberries on the world market (PW). Because the domestic price is lower than the world price, if New Zealand is open to trade there are opportunities for traders to buy strawberries in the domestic market (at the price PD), and sell it on the world market (at the price PW) and make a profit (or maybe the suppliers themselves sell directly to the world market for the price PW). In other words, there are incentives to export strawberries. The domestic consumers would end up having to pay the price PW for strawberries as well, since they would be competing with the world price (and who would sell at the lower price PD when they could sell on the world market for PW instead?). At this higher price, the domestic consumers choose to purchase Qd0 strawberries, while the domestic suppliers sell Qs0 strawberries (assuming that the world market could absorb any quantity of strawberries that was produced). The difference (Qs0 - Qd0) is the quantity of strawberries that is exported. Essentially the demand curve with exports follows the red line in the diagram.

In terms of economic welfare, if there was no international trade in strawberries, the market would operate at the domestic equilibrium, with price PD and quantity Q0. Consumer surplus (the gains to domestic strawberry consumers) would be the area AEPD, the producer surplus (the gains to domestic strawberry producers) would be the area PDEF, and total welfare (the sum of consumer surplus and producer surplus, or the gains to society overall) would be the area AEF. With trade, the consumer surplus decreases to ABPW, the producer surplus increases to PWCF, and total welfare increases to ABCF. Since total welfare is larger (by the area BCE), this represents the gains from trade.

Now consider what would happen if the quantity of strawberry exports was restricted below (Qs0 - Qd0). This is shown in the diagram below as an export quota. Let's say that the quantity of exports is reduced to the amount between B and G on the diagram (about half the amount of unrestricted exports). Now consider what happens to the demand curve (including exports). The upper part represents the domestic consumers with high willingness-to-pay for strawberries. Then there is a limited quantity of exports that can get through the border restrictions, at the world price PW. After that, there are still profit opportunities for domestic suppliers (that is, there are still some domestic consumers who are willing to pay more than what it costs the suppliers to produce strawberries). So, the demand curve (including the export quota) pivots at the point G, and follows a parallel path to the original demand curve (i.e. the demand curve including exports follows the red line in the diagram). The domestic price is the price where supply is equal to demand (P1). The domestic consumers choose to purchase Qd1 strawberries at the price P1, while the domestic suppliers sell Qs1 strawberries at that price. The difference (Qs1 - Qd1) is the quantity of exports. Notice that the price of strawberries that consumers pay has fallen, just as the article linked above noted.

Now consider the areas of economic welfare. The consumer surplus is larger than it was without the restricted exports (it is now the area AJP1), the producer surplus is smaller than it was without the restricted exports (it is now the area P1HF plus the area KLHJ. The first area (P1HF) is producer surplus as if the farmers sold all of their products to the domestic market, while the second area (KLHJ) is the extra profits the farmers get from selling the limited amount of exports that are able to get through the border restrictions. Total welfare is smaller than without the restricted exports (it is now the area AJHF+KLHJ). There is a deadweight loss (a loss of total welfare arising from the restricted exports) equal to the area [BKJ + LCH] - these areas were part of total welfare with trade and no restricted exports, but have now been lost.

The lost exports make strawberry farmers worse off, as well as society overall (in terms of economic welfare in total). However, strawberry consumers are the unwitting recipients of a gain. The interesting thing here is that the government is not responsible for the deadweight loss - this is a deadweight loss caused by a more general disruption in international trade. And it was not just strawberries that were affected - domestic consumers will have been made better off in all exported commodities that cannot be stored for long periods of time.

Why restricting natural gas exports is not a good idea

This week in ECON110 we are covering international trade (and globalisation). The arguments against free trade often focus on the harms to workers (and firms) in import-competing industries - that is, those firms where jobs would be lost by having to compete with lower-cost foreign producers. The counter-argument is that consumers are made better off in these markets by being able to buy the imported products at much lower prices (increasing their consumer surplus).

Much less attention is focused on the impacts of trade restrictions on exporting industries. Consider for example, this 2013 New York Times story about the exporting of natural gas in the U.S.:

As Dow Chemical’s chief executive, Andrew N. Liveris has made himself into something of an outcast among his fellow business leaders.

The reason? He is spearheading a public campaign against increased exports of natural gas, which he sees as a threat to a manufacturing renaissance in the United States, not to mention his own company’s bottom line. But many others say such exports would provide far more benefits to the country than drawbacks, all part of a transformation that promises to increase the nation’s weight in the global economy...

By 2020, new oil and gas production could increase the country’s economic output by 2 to 4 percent beyond what it otherwise would be, add as many as 1.7 million jobs and perhaps reduce the bill for energy imports to zero, according to a report by the McKinsey Global Institute.

“This is a giant turnaround,” said Daniel Yergin, a longtime energy expert and author of a recent book, “The Quest: Energy, Security and the Remaking of the Modern World.” “This is fundamentally improving the competitive position of the United States in the world economy.”

But that windfall is at risk if the government permits natural gas exports to increase quickly, Mr. Liveris warns.

Natural gas is valuable, and on the surface the argument to restrict exports of natural gas in order to keep the value in the U.S. economy makes some intuitive sense. But it would also be quite wrong, and actually make the U.S. worse off.

To see why, let's take a step back and compare an exporting country with trade and without trade. Consider the diagram below, and we'll assume that the U.S. has a comparative advantage in producing natural gas - that means that the domestic price of natural gas (PD) would be below the price of natural gas on the world market (PW). This indicates that U.S. natural gas producers can produce and sell natural gas at a lower cost than foreign producers. Because the domestic price is lower than the world price, if the country is open to trade there are opportunities for traders to buy natural gas in the domestic market (at the price PD), and sell it on the world market (at the price PW) and make a profit (or maybe the suppliers themselves sell directly to the world market for the price PW). In other words, there are incentives to export natural gas. The domestic consumers would end up having to pay the price PW for natural gas as well, since they would be competing with the world price (and who would sell at the lower price PD when they could sell on the world market for PW instead?). At this higher price, the domestic consumers choose to purchase Qd0 natural gas, while the domestic suppliers sell Qs0 natural gas (assuming that the world market could absorb any quantity of natural gas that was produced). The difference (Qs0 - Qd0) is the quantity of natural gas that is exported. Essentially the demand curve with exports follows the red line in the diagram.

We can also use the diagram to demonstrate the gains from trade for an exporting country. Without trade, the market would operate at the domestic equilibrium, with price PD and quantity Q0. Consumer surplus (the gains to domestic natural gas consumers) would be the area AEPD, the producer surplus (the gains to domestic natural gas producers) would be the area PDEF, and total welfare (the sum of consumer surplus and producer surplus, or the gains to society overall) would be the area AEF. With trade, the consumer surplus decreases to ABPW, the producer surplus increases to PWCF, and total welfare increases to ABCF. Since total welfare is larger (by the area BCE), this represents the gains from trade. So, the U.S. is better off with trade, because the total welfare is larger than it is without trade.

Now consider an intermediate case. Instead of having no trade, or having unlimited trade, what would happen if the government allows trade up to some limit? In other words, what happens when there is an export quota? This is demonstrated in the diagram below. Whereas previously, we assumed that the world market could absorb any quantity of exports of natural gas, now the quantity of exports is limited to the agreed quota amount. Let's say that the export quota is limited to the amount between B and G (about half the amount of unrestricted exports). Importantly, the export quota is implemented using licenses - only holders of export licenses are allowed to export natural gas.

Now that there is a quota on exports, consider what happens to the demand curve (including exports). The upper part represents the domestic consumers with high willingness-to-pay for natural gas. Then there is a limited quantity of export demand, at the world price PW. After that, there are still profit opportunities for domestic suppliers (that is, there are still some domestic consumers who are willing to pay more than what it costs the suppliers to produce natural gas). So, the demand curve (including the export quota) pivots at the point G, and follows a parallel path to the original demand curve (i.e. the demand curve including exports follows the red line in the diagram). The domestic price is the price where supply is equal to demand (P1). Export license holders can purchase natural gas at this price, and then sell it on the world market and receive the higher world price (PW), and pocket a profit. The domestic consumers choose to purchase Qd1 natural gas at the price P1, while the domestic suppliers sell Qs1 natural gas at that price. The difference (Qs1 - Qd1) is the quantity of exports (which is also the quantity of the quota).

Now the consumer surplus is larger than it was without the export quota (it is now the area AJP1), the producer surplus is smaller than it was without the export quota (it is now the area P1HF). The export license holders now receive a surplus (profit), equal to the area KLHJ. Total welfare (which is now made up of the consumer surplus, producer surplus, and license holder surplus) is smaller than without the export quota (it is now the area AJHF+KLHJ). There is a deadweight loss (a loss of total welfare arising from the export quota) equal to the area [BKJ + LCH] - these areas were part of total welfare with trade and no export quota, but have now been lost.

Importantly though, note that the total welfare area is larger with the export quota (AJHF+KLHJ) than with no trade at all (AEF). So, the argument that restricting exports of natural gas makes the U.S. better off and will "fundamentally improve the competitive position of the U.S. economy" is simply untrue. Up to the point where the market-determined quantity of natural gas is exported, there are gains to be had from additional exports. That doesn't mean that more exports are always better. For instance, export subsidies that increase exports beyond the quantity shown in the first diagram above are also bad. And, you might want to restrict natural gas production for environmental reasons (which haven't been accounted for in the diagrams above). But those are stories for another day.

Read more:

• Why export quotas probably failed to help coffee farmers

Why export quotas probably failed to help coffee farmers

Last year, my wife and I both read the same story from Daily Coffee News, entitled "A Brief History of Coffee Price Volatility in the Modern Era (1963-2013)". Probably unsurprisingly given our different disciplinary backgrounds, we had completely different takeaways from the story. On the one hand, you could take away that free market forces are a bad thing, because they led to volatility in the price of coffee on world markets - as the International Coffee Organization is quoted in the article as saying, this "makes it difficult for roasters to control processing costs and affects profit margins for traders and stockholders, making their activities less attractive".

What I took away from the article was how the International Coffee Organization ensured price stability in the period from 1963 to 1989 - by using a system of export quotas in producing countries. My overall comment was "wow, the coffee farmers were probably worse off, but I bet the middlemen were happy". And now I'll explain why (which I've been promising my wife I would do here for some time).

Let's start with an exporting country - a country that has a comparative advantage producing the product (coffee in this case). That means that the country can produce coffee at a lower opportunity cost than other countries. On a supply-and-demand diagram like the one below, it means that the domestic market equilibrium price of coffee (PD) would be below the price of coffee on the world market (PW). Because the domestic price is lower than the world price, if the country is open to trade there are opportunities for traders to buy coffee in the domestic market (at the price PD), and sell it on the world market (at the price PW) and make a profit (or maybe the suppliers themselves sell directly to the world market for the price PW). In other words, there are incentives to export coffee. The domestic consumers would end up having to pay the price PW for coffee as well, since they would be competing with the world price (and who would sell at the lower price PD when they could sell on the world market for PW instead?). At this higher price, the domestic consumers choose to purchase Qd0 coffee, while the domestic suppliers sell Qs0 coffee (assuming that the world market could absorb any quantity of coffee that was produced). The difference (Qs0 - Qd0) is the quantity of coffee that is exported. Essentially the demand curve with exports follows the red line in the diagram.

We can also use the diagram to demonstrate the gains from trade for an exporting country. Without trade, the market would operate at the domestic equilibrium, with price PD and quantity Q0. Consumer surplus (the gains to domestic coffee consumers) would be the area AEPD, the producer surplus (the gains to domestic coffee producers) would be the area PDEF, and total welfare (the sum of consumer surplus and producer surplus, or the gains to society overall) would be the area AEF. With trade, the consumer surplus decreases to ABPW, the producer surplus increases to PWCF, and total welfare increases to ABCF. Since total welfare is larger (by the area BCE), this represents the gains from trade. So, coffee farmers are better off with trade, because the producer surplus is larger than it is without trade.

What happens when there is an export quota? This is demonstrated in the diagram below. Whereas previously, we assumed that the world market could absorb any quantity of exports of coffee, now the quantity of exports is limited to the agreed quota amount. Let's say that the export quota is limited to the amount between B and G (about half the amount of unrestricted exports). Importantly, the export quota is implemented using licenses - only holders of export licenses are allowed to export.

Now that there is a quota on exports, consider what happens to the demand curve (including exports). The upper part represents the domestic consumers with high willingness-to-pay for coffee. Then there is a limited quantity of export demand, at the world price PW. After that, there are still profit opportunities for domestic suppliers (that is, there are still some domestic consumers who are willing to pay more than what it costs the suppliers to produce coffee). So, the demand curve (including the export quota) pivots at the point G, and follows a parallel path to the original demand curve (i.e. the demand curve including exports follows the red line in the diagram). The domestic price is the price where supply is equal to demand (P1). Export license holders can purchase coffee at this price, and then sell it on the world market and receive the higher world price (PW), and pocket a profit. The domestic consumers choose to purchase Qd1 coffee at the price P1, while the domestic suppliers sell Qs1 coffee at that price. The difference (Qs1 - Qd1) is the quantity of exports (which is also the quantity of the quota).

Now the consumer surplus is larger than it was without the export quota (it is now the area AJP1), the producer surplus is smaller than it was without the export quota (it is now the area P1HF). The export license holders now receive a surplus (profit), equal to the area KLHJ. Total welfare (which is now made up of the consumer surplus, producer surplus, and license holder surplus) is smaller than without the export quota (it is now the area AJHF+KLHJ). There is a deadweight loss (a loss of total welfare arising from the export quota) equal to the area [BKJ + LCH] - these areas were part of total welfare with trade and no export quota, but have now been lost.

Of most interest to us though is that the export quotas don't help the coffee farmers - producer surplus has fallen. In contrast, the export license holders (the middle men, who buy coffee from the farmers and sell it on the world market) are made better off by the export quota system.

But wait - what if the export quota system makes world coffee prices higher? That seems a reasonable possibility - if all coffee producing countries are restricting the supply of coffee to the world market, then that should raise prices for all. I'm sure that's what the International Coffee Organization was probably trying to do all along.

The diagram below demonstrates what happens, if the quota is kept the same size as the previous diagram, but the world price increases from PW to PX. The demand curve (including the export quota) now follows the purple path (since the license holders can now sell at the higher price PX instead of PW), but notice that the resulting domestic price is exactly the same (P1). In terms of welfare effects, the resulting consumer surplus and producer surplus are unchanged even though the world price is now higher. The license holder surplus increases to MNHJ.

So, even if the export quota system successfully raises the world price of coffee, it is the middle men who benefit, not the coffee farmers. Which is why, after the coffee export quota system collapsed in 1989, we would expect coffee farmers to have been made better off.

[Update: Fixed missing label in second diagram]