The global macroeconomics of a trade war

贸易战的全球宏观经济学

2019/04/25 00:00
对照中文英文原文
不断增加的保护主义将减缓世界贸易,并可能抑制全球经济增长。

Increasing protectionism will slow down world trade and may dampen global economic growth. This column examines the global macroeconomic consequences of a major trade conflict between the US and China, and shows that the two countries would be the biggest losers from a 10% ‘tit-for-tat’ trade war between them. As long as it does not get involved in the conflict, the euro area may temporally gain from trade diversion, as competitiveness improves and imports from regions whose exports are blocked elsewhere become cheaper.

不断增加的保护主义将减缓世界贸易,并可能抑制全球经济增长。本专栏探讨了中美之间重大贸易冲突的全球宏观经济后果,并表明这两国将是他们之间10%“针锋相对”贸易战中最大的输家。只要它没有卷入冲突,欧元区可能暂时从贸易转移中获益,因为竞争力提高,从其他地方出口受阻的地区进口变得更便宜。

After a decades-long gradual move towards free trade, US President Donald Trump has recently shaken the foundations of the global trading system by imposing steep tariffs on imports from China and other countries.1 It is not yet clear how the US-China trade conflict will end, but there is widespread concern that an ongoing trade war between the two largest world economies may derail the recovery from the Global Crisis (Berthou et al. 2019).

经过长达数十年的自由贸易逐渐走向,美国总统唐纳德特朗普最近通过对来自中国和其他国家的进口产品征收高额关税,动摇了全球贸易体系的基础.1目前尚不清楚美中贸易冲突如何将会结束,但人们普遍担心两大世界经济体之间持续的贸易战可能会破坏全球危机的复苏(Berthou等,2019)。

To gauge the macroeconomic effects of a trade war between the US and China, we use the De Nederlandsche Bank (DNB) variant of the ECB’s multi-region, general equilibrium EAGLE (Euro Area and Global Economy) model. This model encompasses the world economy and models bilateral trade flows and their relative prices for each region explicitly. Imposing trade tariffs in the model harms world output, while causing trade diversion towards the euro area. Output in the US and China contracts as their bilateral exports drop. Instead, the euro area may benefit from an appreciated effective exchange rate that boosts private consumption.

为了衡量美中贸易战的宏观经济影响,我们使用了欧洲央行多区域,一般均衡EAGLE(欧元区和全球经济)模型的De Nederlandsche Bank(DNB)变体。这种模式包括世界经济,并明确模拟双边贸易流量及其各区域的相对价格。模型中强加的贸易关税损害了世界产出,同时导致贸易转向欧元区。随着双边出口下降,美国和中国的合同产量下降。相反,欧元区可能会从提高私人消费的升值有效汇率中受益。

The EAGLE model with tariffs

EAGLE模型与关税

EAGLE is an open economy DSGE model that accounts for international macroeconomic interdependence – within the  euro area, but also globally (Gomes et al. 2012). It contains four regions: the home country (in this case, the Netherlands), the rest of the euro area, the US, and the rest of the world (RoW). We take the RoW as representing China (and other non-EU targets of current US trade policy).

EAGLE是一个开放经济的DSGE模型,它解释了国际宏观经济的相互依赖 - 在欧元区内,但也在全球范围内(Gomes等,2012)。它包含四个区域:本国(在本例中为荷兰),欧元区其他国家,美国和世界其他地区(RoW)。我们将RoW视为代表中国(以及当前美国贸易政策的其他非欧盟目标)。

We extend the model to allow for import tariffs. In the model, setting a tariff on imports translates in to imposing a distortionary tax on the marginal cost of exporters. Specifically, when the US imposes tariffs on imported intermediate goods from China, it essentially imposes a tax on Chinese exporters to the US. The US fiscal authorities then collect those revenues and rebate them lump-sum to US households. A similar mechanism holds when China imposes tariffs on imported intermediate goods from the US.

我们扩展该模型以允许进口关税。在该模型中,设定进口关税意味着对出口商的边际成本征收扭曲税。具体而言,当美国对来自中国的进口中间产品征收关税时,它基本上对中国出口商征税。然后,美国财政部门收取这些收入并将其一次性退还给美国家庭。当中国对来自美国的进口中间产品征收关税时,类似的机制就成立了。

Given the downward-sloping demand curve and the upward-sloping supply curve that monopolistically competitive firms face, the tax burden is shared between the (domestic) consumer and the (foreign) producer. A higher elasticity of substitution between product varieties implies less market power – then exporters bear most of the tax burden and vice versa. The model outcomes display Lerner-symmetry – import tariffs are equivalent to export taxes.2 That is, higher tariffs lead to lower imports but, equally, to lower exports. The trade balance response depends on what happens to intertemporal variables (e.g. real interest rates, and gradual changes in the real exchange rate, possibly phasing out tariffs).

鉴于垄断竞争企业面临的需求曲线向下倾斜和供给曲线向上倾斜,税收负担由(国内)消费者和(外国)生产者共享。产品品种之间更高的替代弹性意味着更低的市场力量 - 然后出口商承担大部分税收负担,反之亦然。模型结果显示勒纳对称性 - 进口关税等同于出口税.2即,较高的关税导致进口量下降,但同样也导致出口下降。贸易平衡响应取决于跨期变量会发生什么(例如实际利率,实际汇率的逐步变化,可能逐步取消关税)。

Macro impact of a US-China trade war

美中贸易战的宏观影响

Consider a tit-for-tat US-China trade conflict where the US imposes a permanent 10% tariff on all Chinese imports. China retaliates after one quarter with a similar tariff on all US exports to China. Figure 1 shows the global impact. The US trade actions have a significantly negative impact on world output that eventually declines further once the Chinese retaliate. In the graph, one period corresponds to a quarter.

考虑一场针锋相对的美中贸易冲突,美国对所有中国进口产品征收10%的永久关税。中国在一季度后对中国所有出口产品征收类似关税进行报复。图1显示了全球影响。美国的贸易行为对世界产出产生了显着的负面影响,一旦中国进行报复,最终会进一步下滑。在图中,一个周期对应于四分之一。

After five years, aggregate world output is over 0.5% below the baseline (‘steady state’). When China retaliates, world output falls initially less when only the US imposes tariffs. The Chinese retaliation substantially offsets the real appreciation of the dollar and there is a much stronger European increase in demand as China switches its exports from the US to the euro area. However, as relative prices adjust, the negative effects on US and Chinese investment eventually lead to lower world output after all.3

五年后,世界总产出低于基线(“稳态”)超过0.5%。当中国报复时,只有美国征收关税时,世界产量最初下降。中国的报复大幅抵消了美元的实际升值,随着中国将出口从美国转向欧元区,欧洲的需求增长强劲得多。但是,随着相对价格的调整,对美国和中国投资的负面影响最终导致世界产出下降

Figure 1 Effect on world output from US-China import tariffs

图1美中进口关税对世界产出的影响

In Figures 2, 3, and 4, we display the responses of key macro variables in each region. Consider first US tariffs on Chinese exporters only (solid blue line). A striking result is the decline in GDP in the US itself once it imposes the tariffs on imports from China. Employment declines as tariffs also lead to lower exports from, and lower investment in, the US. Although tariffs imply a subsidy to domestic producers, they also imply a tax on all users of imported goods, an effect that worsens the impact on short-run output. Consumption in both variants declines and investment slows down, amplifying the decline in output. This is the Lerner symmetry theorem at work – import tariffs are equivalent to export taxes. A striking result is that the US tariffs initially lead to a deterioration in the US trade balance as lower output more than offsets the fall in investment and consumption.

在图2,3和4中,我们显示了每个区域中关键宏变量的响应。首先考虑美国对中国出口商的关税(实线蓝线)。一个明显的结果是,一旦对来自中国的进口征收关税,美国本身的国内生产总值就会下降。就业下降,因为关税也导致美国出口减少和投资减少。虽然关税意味着对国内生产者的补贴,但它们也意味着对所有进口商品的使用者征税,这种影响会加剧对短期产量的影响。两种类型的消费都在下降,投资放缓,放大了产量的下降。这是工作中的勒纳对称定理 - 进口关税等同于出口税。一个引人注目的结果是,美国的关税最初导致美国贸易平衡恶化,因为产量下降抵消了投资和消费的下降。

Figure 2 Effects on US (quarters on horizontal axis)

图2对美国的影响(横轴为四分之一)

Note: The blue solid lines depict the responses when the US imposes tariffs on Chinese exporters, The black dashed lines add in China’s retaliation. A higher real effective exchange rate (REER) implies a depreciation.

注:蓝色实线描绘了美国对中国出口商征收关税时的反应,黑色虚线增加了中国的报复。较高的实际有效汇率(REER)意味着折旧。

Chinese retaliation (black dashed lines) adds significant injury to the US. US output contracts more, as do the other macro-indicators. China similarly sees a significant slowdown in GDP and investment.

中国的报复(黑色虚线)给美国带来了重大伤害。与其他宏观指标一样,美国产出收缩更多。中国同样看到GDP和投资大幅放缓。

Figure 3 Effects on China (quarters on horizontal axis)

图3对中国的影响(横轴为四分之一)

Note: The blue solid lines depict the responses when only the US imposes tariffs on Chinese exporters. The black dashed lines add in China’s retaliation. A higher real effective exchange rate (REER) implies depreciation.

注:蓝色实线表示只有美国对中国出口商征收关税时的回复。黑色的虚线增加了中国的报复。较高的实际有效汇率(REER)意味着折旧。

The euro area has some short-run benefits though. It benefits from the trade flow effects of the trade war. Chinese exports are now diverted to the euro area at lower prices. Equally, prices of Chinese goods in the US (post-tariff) go up, which improves the euro area’s export competitiveness vis-à-vis Chinese exporters in the US. The employment across regions shows striking differences (figure 4 below) – China and the US hurt each other significantly, but European employment picks up as exports become more competitive in the US and Chinese imports become cheaper.

欧元区虽然有一些短期利益。它受益于贸易战的贸易流动效应。中国出口现在以较低的价格转移到欧元区。同样,美国的中国商品价格(关税后)也在上升,从而提高了欧元区对中国出口商在美国的出口竞争力。各地区的就业情况存在显着差异(见下图4) - 中国和美国相互之间存在巨大冲突,但随着出口在美国的竞争力提高以及中国进口商品变得更便宜,欧洲就业人数增加。

Figure 4 Regional employment responses (quarters on horizontal axis)

图4区域就业反应(横轴为四分之一)

Figure 5 gives more details about the impact on Europe. The US tariffs lead to higher European exports to the US as European competitiveness against Chinese exporters improves. And imports from China increase as Chinese producers divert goods to the euro area.

图5提供了有关对欧洲影响的更多细节。随着欧洲对中国出口商的竞争力提高,美国关税导致欧洲对美出口增加。随着中国生产商将商品转移到欧元区,来自中国的进口增加。

Figure 5 Effects on euro area (quarters on horizontal axis)

图5对欧元区的影响(横轴为四分之一)

Note: The blue solid lines show the responses when only the US imposes tariffs on Chinese exporters. The black dashed lines add in China’s retaliation. An increase in the real effective exchange rate (REER) and the real exchange rate (RER) corresponds to a depreciation.

注:蓝色实线表示只有美国对中国出口商征收关税的回复。黑色的虚线增加了中国的报复。实际有效汇率(REER)和实际汇率(RER)的增加对应于折旧。

Conclusion

结论

The analysis, stylised as it is, yields some stark conclusions. Whether tariff wars “are easy to win” we do not know, but they do inflict real harm on the US itself. Even the 10% tit-for-tat tariff war leads to almost a full percentage point lower output for several years running and a decline in consumption and investment. China experiences similar effects. In line with economic theory, the import tariff acts like an export tax – US exports decline significantly as their competitiveness is undermined by the appreciating dollar.

分析,风格化,得出一些明确的结论。关税战争是否“容易获胜”我们不知道,但它们确实对美国本身造成了实际伤害。即使是10%针锋相对的关税战,导致几年来产量几乎降低了整整一个百分点,并且消费和投资也在下降。中国也有类似的影响。与经济理论一致,进口关税就像出口税一样 - 美国出口大幅下降,因为美元升值削弱了它们的竞争力。

While two dogs (the US and China) are fighting for a bone, a third (the euro area) runs away with it. That is, the euro area may benefit from the US-China trade conflict in the short-run. The analysis suggests that as long as it does not get involved in the conflict, the euro area profits from cheaper imports from China as they get diverted from the US, and it gains improved competitiveness in the US in response to tariffs against the Chinese and the appreciating dollar. This differential impact also shows in the employment responses – down in the US and China but up in the euro area. But overall the global impact of the US trade actions is negative for world output and even more so when the Chinese retaliate.

虽然有两只狗(美国和中国)正在争夺骨头,但是第三只(欧元区)却随之而去。也就是说,欧元区可能在短期内受益于美中贸易冲突。分析表明,只要它没有卷入冲突,欧元区就会从中国进口更便宜的进口中获利,因为它们从美国转移,并且在对美国的关税和中国的关税方面提高了竞争力。欣赏美元。这种差异影响也表现在就业反应中 - 在美国和中国下降,但在欧元区上升。但总的来说,美国贸易行动的全球影响对世界产出是负面的,而当中国报复时则更是如此。

为提升阅读体验,智堡对本页面进行了排版优化 查看原文