本文是網易研究局獨家稿件，轉載請註明來源
作者|金刻羽（哈佛經濟學博士、倫敦政治經濟學院經濟學終身教授）
從許多方面來看，全球經濟目前的狀況已經超過了1930年代的大蕭條。很多世界聞名的經濟學家，例如2018年諾貝爾獎獲得者保羅·羅默，已經將當前的經濟衰退等同於1930年代的大蕭條，而不是2008年的衰退。我們要做的是分析一些數字。
在美國，股市從今年的峰值下跌了35％到本季度的最低點。[1] 信貸市場已經失靈，垃圾債券的信貸息差比國庫券高出的基點從300點升至超過1000點。[2]我們對經濟的預期越來越悲觀，主流政府和金融機構預測第二季度產出將下降25％至35％。[3][4]在短短2周的時間內，美國申請失業救濟金人數超過660萬，創下歷史新高。[5]在2008年經濟衰退的過程中，美國共損失了880萬個工作崗位。[6]美國財政部長史蒂夫·姆努欽（Steve Mnuchin）預測，到今年夏天，美國失業率可能會上升到20％[7], 甚至更高。
但是，這次經濟事件與大蕭條之間的主要區別在於，大蕭條從1929年開始爆發，對股市和就業市場的影響過了三年才有所體現，這次大約只花了三個星期！
大多數專家已經相信，與2008年的大衰退相比，這次經濟衰退將更加嚴重。幾乎已經沒有人再持有一季度GDP僅僅下降10％，並實現強勁的V型復甦這種溫和衰退的想法。隨著越來越多的數據出爐，這些觀點變得越來越站不住腳。而正如我們已經看到的那樣，經濟經歷了自由落體的過程，幾乎所有的經濟體都停止了運轉——這種情形甚至在大蕭條時期都沒有看到過。
如果當前全球經濟下行的範圍和程度已經可以大蕭條相提並論，甚至比大蕭條還要嚴重，那麼真正的問題是這會持續多久。經濟是像大蕭條之後出現「 L」形的長期停滯，需要十年的時間才能恢復，還是會更快恢復？我認為目前還沒有確定的結論，因為我們對以下三件事尚未足夠了解：1）新冠疫情的流行是否可以被控制；2）疫情在秋季是否會出現第二輪擴散；3）世界各國的政策力度、覆蓋範圍和有效性。
如果有人告訴你，他們知道這些問題的答案，請不要相信他們。
首先，沒有人可以肯定各國採取的緩和措施是否有效。極為諷刺的是，前不久川普還公開宣布這只是一種普通流感，沒有什麼可擔心的，幾周後他就向美國公民宣布，如果」只有」10萬至24萬人死亡，那就說明他的工作很出色！
美國的確診病例已經超過中國，而且這一數字還在不斷攀升。美國的緩和策略或半緩和策略並不一定能夠阻止病毒傳播。兩天前，人們還可以自由前往佛羅裡達州的海灘，那裡的居民大多數都在65歲以上。對美國來說，最樂觀的情況是像日本和韓國那樣，緩和措施已經奏效，確診人數增長趨於平緩。但是日本和韓國這些國家進行了很多次病毒檢測，並且隔離措施高度嚴格。而美國真的達到了這個標準嗎？
第二，即使在本國，我們也不能排除第二輪傳染的發生。它可能在復工時發生，也可能在秋天發生。病毒隨時可能發生突變，並且以更大的侵略性襲擊人類。西班牙大流感突變了幾次，而第二波是最致命的。
此外，入境封鎖措施能持續多久？只要世界上某些地區還沒有控制住病毒/疫情——比如很多發展中國家會很快淪陷——入境封鎖就必須存在。但是封鎖邊境意味著GDP的損失。
中國的復甦進程與歐洲和美國等其他經濟體相比是相當樂觀的。我們不能指望全球供應鏈會立刻恢復正常，也不能指望美國的失業工人能夠立即找到工作。實際上，由於疫情過後很多公司將開始更多地使用數位化技術，很多人將面臨永久性失業。我們也不能假設需求端會立刻恢復正常：如果你習慣了每周去餐廳3次，像美國人或歐洲人那樣每周看一次電影，那麼你會通過每周去6次餐廳並且看兩次電影來彌補失去的這部分需求嗎？不會。那部分需求會永遠消失。
正如經濟學家約翰·科克倫（John Cochrane）所說，這就像重啟核反應堆一樣，你無法將其關閉然後立刻重新打開，這需要花時間。重啟的過程越拖延，經濟損失就越大。
第三，我們假設現在是最樂觀的情況，各國政府採取的政策都是正確有效的——那麼這意味著世界主要經濟體的衛生政策、貨幣和財政政策都必須毫不猶豫地協同工作。
你會認為歐美政府承諾的無限量化寬鬆、無限流動性、「盡其所能」的政策預示著好消息嗎？某種意義上講，這是個好消息，因為如果不採取這些政策，情況將會更糟。或者也可能正好相反——政府已經預料到情況將會非常糟糕，所有這些激進的政策都預示著我們已經做好了面對這些最壞情況的準備。
這就是為什麼我們會看到世界主要經濟體會採取如此迅速而積極的措施。非常規貨幣政策方案在美國和歐洲實施通常需要3年時間，而這次只用了3周。通常美國政府需要幾個月時間才能通過7,000億美元的救助方案，而這次只用了幾天時間就通過了規模2萬億的刺激計劃。我們認為這是個好消息，但實際上它預示的結果是非常負面的。這就是貨幣政策的「信號效應」，是我目前一直正在研究的學術前沿。
刺激計劃的成功要求對所有的流動性：從企業到家庭，再到金融機構的償付能力在很長的一段時間內有所限制——直到找到解決方案。但是沒有人能確定這會持續多長時間。
此外還有滯脹的問題——是否會出現經濟滯脹和通貨膨脹？我認為西方國家不會出現通貨膨脹，但也有觀點認為如果中東國家發生戰爭，除了石油價格可能暴漲外，嚴重的負供給衝擊也可能使我們陷入類似1970年代的滯脹。我仍然認為，西方國家總需求不足的局面將會持續存在，所以通貨膨脹的情況可以得到緩解，但通貨膨脹對中國而言卻是合理存在的風險。
隨著數據的持續更新，這些觀點也會有所調整。在接下來的幾周內，我們將會看到西方國家的緩解對策是否有效，世界上其他地區是否會出現二次感染，以及幾個月後，會不會有疫苗的出現。我們仍然不知道秋冬季節是否會出現新一輪的傳染，也不知道經濟何時才能真正恢復正常。我們必須記住：決定時間線的是病毒，而不是經濟學家。經濟學家本來就決定不了任何事情，現在這種可能性更小。
附英文原文：
Economic Depression is now the new Reality
By many measures, the global economy has already surpassed the Great depression of the 1930’s. Famous economists around the world, such a the recent Nobel Laureate Paul Romer, are already equating the current economic downturn to the Great Depression of the 1930’s, not the recession of 2008. Recent Nobel Laureate Paul Romer is one just example. But all we have do to is to look at the numbers. Equity markets from its peak this year to its lowest point this quarter has fallen by 35% in the U.S.[1] Credit markets already have already seized up, with credit spreads on junk bonds going from 300 to more than 1000 basis points above treasury bills.[2] Projections of the economy are going down by the day, as mainstream government and financial institutions predict a 25% to 35% loss of output in the second quarter.[3][4] And in a matter of 2 weeks, 6.6 million Americans have filed for unemployment benefit.[5] The total number of employment loss over the entire course of the Great Recession of 2008 in the U.S. was 8.8 million jobs.[6] The Projections from the Treasury secretary Steve Mnuchin is that the U.S. unemployment rate can go up to 20% by this summer.[7]
However, the main difference between this episode and the Great depression is that it took 3 years from the trigger in 1929 for this to transpire. This time around---it only took three weeks!
By now, virtually everyone has abandoned the idea of a mild recession of a 10% drop in GDP first quarter and a strong V-shaped recovery. But as we get more and more data coming in, these views are getting grimmer and grimmer by the day, by the week, and as we have already seen, the economy has experienced a free-drop---virtually a complete halt of all economic activity---something that was not even seen during the Great Depression.
If the size and depth of the current global downturn is worse than the Great Depression, the real question is how long this will last. A danger is that trend output will be permanently lower, and that even when the economy normalizes the countries will be on a permanently lower growth path. This is exactly what happened to countries like the U.K. There will be permanent losses of output, and many jobs which have been destroyed will never come back again. The longer is the protracted recession, the lower the long run trend growth will be.
Will wel see an 『L』 shaped long stagnation like the period after the great depression, where it took ten years to recover, or will it recover much sooner? I don’t think anyone can say with certainty at this point given that we have insufficient information about what will happen to 3 things: the pandemic and whether it can be suppressed; 2) whether there will be a second wave of infection in the fall 3) the extent and scope and effectiveness of government policies around the world.
If anyone tells you they know these answers, don’t believe them.
First, nobody has confidence on whether mitigation strategies work. It is ironic that weeks after President Trump declared this to be a normal flu and that there is nothing to worry about, he announced to the American citizens that if 『only』 100k-240k people die he would have done a terrific job!
Already, the U.S. has more infected cases than is registered in China, with numbers still climbing by the day. America’s mitigation policies, or, half-mitigation policies---is not sure to be able to stop the spread of the virus. As of two days ago, people were still going freely to the beach in the state of Florida, where most of residents are above the age of 65. For America, the most optimistic scenario is to be like Japan and Korea, where mitigation has worked, and curves have flattened out. But in those countries they had done a lot of testing, as well as high degrees of self-discipline on social distancing and isolation on the part of the people. Are Americans really living up to that standard?
Second, we cannot rule out a second wave of infections---even in this country. It can come about when work re-normalizes, but it can also come about in the autumn, perhaps with a mutation, and attack the population with even greater force and aggression. The Spanish flu mutated several time, with the second wave being the most deadly.
And, how long can borders remain closed? So long as some part of the world has not contained the virus---and there will be plenty of developing countries that will soon rise up that curve---borders will have to remain. But closed border means a loss of GDP.
By looking at China’s recovering and projecting it onto other economies like Europe and the US is highly optimistic. We cannot expect that global supply chains will just go back to normal as before, and we cannot expect that unemployed workers in the U.S. will find jobs immediately. In fact, many of them will have a permanent loss of jobs because companies will start to adopt more digital technologies after this crisis. We also cannot assume that demand will go back to normal right away. If you were used to go to the restaurant 3 times a week and the movie theatre once a week, as an American or European, are you going to make up for lost time by eating out 6 times a week and going to movies twice a week? No. That part of output is permanently lost.
As the economist John Cochrane said, this is like restarting a nuclear reactor. You cannot turn it off and switch it on right back again. It will take time. And the more protracted is this process of restarting, the greater the economic loss.
Third, the optimistic scenario assumes that all of the right policies are in place—this means health policies, monetary and fiscal policies in the major economies in the world all have to work conjunctionally, and without any hesitation.
Do we think that this unlimited quantitative easing, unlimited liquidity, `doing it whatever it takes』 promised by the European and American governments signal good news? In some ways yes, it is good news, because we would be in an even worse situation in their absence. Or---it could mean just the opposite---they are expecting that times are going to get really bad, so all of this aggressive policies is signalling that we are braced for a really bad run.
This is actually why we are seeing such a swift and active response from the major players around the world. Whereas the whole package of the unconventional monetary policy took 3 years to implement in US and Europe, this time it took 3 weeks. Whereas it took the U.S. government months to pass a rescue package of 700 billion dollars, it took less a few days to pass a bill 2.5 times that amount. We think that this is good news, but in fact what it is signalling is very, very bad news to come. This is the 『signalling effect』 of monetary policy that has been at the frontier of academic research, which I’m also currently working on.
The success of the policy requires it to keep a lid on all liquidity, solvency problems from businesses to households to financial institutions---for a long time to come---until there is a solution. But how long will this take ? no one knows for sure.
There is also the question of stagflation----will there be stagnation and inflation? I’m not of the view that inflation is about to hit the Western economies, but there is also the compelling argument that a heavy negative supply shock in addition to a possible oil price spike if there is war in the middle east may cast us in another run of the 1970’s stagflation experience. I still believe that there is persistent aggregated demand deficiency in the West to level that off, but inflation is not an unreasonable risk for our own country.
These views should adapt as new data comes in. In the next few weeks, we will know whether mitigation strategies work, whether there is a new round of infections in some parts of the world, and in a few months』 time we will know whether a vaccine is more likely. We still do not know whether there will be a new wave in the fall and winter, and we do not know when the economy can realistically return to normal. We have to remember: it is the virus that determines the time line, it is not the economists. It never has been, but even less likely now.
注釋：
[1] 2020年2月12日，道瓊指數創下歷史新高29551點，但12天後的2月24日，美國股市迎來歷史性下跌通道，截止3月20日曆時25天，道瓊指數已跌至19173點，跌幅35%。
[2]https://www.bloomberg.com/news/articles/2020-03-21/u-s-junk-bonds-enter-distress-spreads-top-1-000-basis-points
[3]http://finance.eastmoney.com/a/202003301437210439.html
[4]https://fortune.com/2020/03/23/morgan-stanley-goldman-sachs-estimate-coronavirus-economic-pain/
[5]https://www.bloomberg.com/news/articles/2020-04-02/u-s-jobless-claims-doubled-to-record-6-65-million-last-week
[6]https://www.bls.gov/opub/mlr/2011/04/art1full.pdf
[7]https://www.cnbc.com/2020/03/18/mnuchin-warns-senators-of-20percent-us-unemployment-without-coronavirus-rescue-source-says.html
【推薦】重磅報告！百位經濟學家預判2020經濟和投資趨勢
購買方式：
第一步：
掃描下面的付款碼付款：
如果購買 嘗鮮版 （可以看本報告前兩部分，「宏觀經濟信心」和「宏觀經濟指標」）， 請掃碼支付19元。
如果購買 完整版 （可以看報告5個部分的全部內容）， 請掃碼支付29元。
（如您是客戶端用戶，請將本文分享到微信打開，或保存圖片/截圖在微信打開，再在微信客戶端進行支付。）
（微信付款碼）
（支付寶付款碼）
第二步：
添加網易財經官方微信獲取報告（如遇交易問題，也可直接添加小仙女微信轉帳支付）
完成付款後，請掃描下面的二維碼，添加網易財經官方微信「後廠村小仙女」，把付款成功的截圖發給小仙女，收到截圖後，小仙女會立即發送報告給您。
（特殊提示：如您在晚11點-早7點之間下單，可能會遇到延遲回復的情況，仙女也需要休息哦~）