天不下雨，皇帝最急

世界急需用水，澳大利亚也正在迅速地转变成了一个满是干旱尘暴的地方。希腊有着数不尽的森林大火，日本的热浪正在造成前所未有的惨烈死亡。 如果你是个独裁者，你现在肯定会非常担心。为什么呢?

Canadian economic historians from Brock University and St Francis Xavier University have looked at the political assassinations of the ancient Roman Empire and attempted to cook up an equation that can help to explain when and why they occurred. Their findings are published in Economic Letters.

来自布洛克大学和圣方济各泽维尔大学的加拿大经济历史学家研究了古罗马帝国的政治暗杀事件，并试图建立一个方程式，以解释这些事件发生的时间和原因。 他们的研究结果发表在《经济学快报》上。

Bad decisions and bad friends certainly played a role, however, rain is the decisive factor, it seems.

他们发现，错误的决定和不怀好意的党羽的确都是原因之一，但好像，雨水才是最重要的因素。

Being a Roman leader was a very dangerous job, in general. The Roman Empire, from 27 BCE to 476 CE, had a total of 82 emperors, 20 percent of whom were assassinated or murdered in a politically motivated attack.

回顾往昔，可以说做罗马领袖是一项非常危险的工作了：罗马帝国，一直从公元前27年到公元476年，这期间共有82个皇帝，其中20% 都因政治因素而惨遭暗杀或谋杀。

The years of 235 CE to 285 CE were bloody in the northeastern empire, even by Roman standards. Over the course of these 50 years, 14 out of 26 emperors were assassinated.

在公元235年到285这短短五十年中，用腥风血雨来描述可谓一点也不夸张：在位的帝王共26位，其中14位死于暗杀。

The factor that appears to be consistent throughout these assassinations is that the previous year hadn’t seen much rain. In fact, a significant reduction in rainfall would increase the likelihood of an assassination by 11 percent. The researchers gathered their data from another study that collected information from over 7,000 rainfall-sensitive oak tree rings across France and eastern Germany.

这些暗杀事件中似乎始终如一的因素是，前一年没有出现太多的降雨。事实上，降雨量的大幅度减少会使暗杀的可能性增加11% 。研究人员从另一项研究中收集了他们的数据，该研究收集了法国和德国东部7,000多个降雨敏感橡树林的信息。

The Roman economy was largely agricultural, meaning a drought could easily lead to food shortages. Soldiers, especially in the northern empire, were particularly reliant on local food sources and would be hit the hardest by starvation. A hungry soldier is an unhappy soldier, so this could lead to a massively disgruntled military. If there’s one rule for dictators, it’s don’t annoy your military, as they are perhaps your strongest pillar of power.

罗马主要依靠农业经济而发展，这意味着干旱很容易导致粮食短缺。士兵，尤其是北方帝国的士兵，特别依赖当地的食物来源，而且会因饥饿而受到最严重的打击。一个饥饿的士兵会满腹骚怨，所以这可能使得一支军队都变得躁动不安。 如果说独裁者有一条不可触碰的底线，那这条底线就是不要激怒你的军队，因为他们可能是你最强大的力量来源。

“Our chain of causation is as follows. When there's less rainfall, there are lower crop yields. This, in turn, causes Roman frontier troops to starve, which increases the risks of mutinies. Such troop discontent can, in turn, lead to assassinations,” study author Cornelius Christian, of Brock University, told IFLScience. "We find evidence consistent with this."

研究报告的作者、布洛克大学的科尼利厄斯 · 克里斯蒂安告诉 IFLScience："我们建立的因果关系链如下：降雨量减少时，作物产量就会降低，导致罗马边防部队挨饿，从而增加了兵变的风险，而部队的不满反过来会导致暗杀,我们也的确发现了与此相符的证据。"

“Systemic reviews suggest that drought increases the risk of conflict, even in modern times,” Christian added. "A striking historical example is the French Revolution: a paper by Maria Waldinger of the London School of Economics shows that, across France, drought and crop failures predict more peasant uprisings in 1789. In more modern times, drought in India predicts Naxalite rebel violence."

"系统性审查表明，即使在现代，干旱也会增加冲突的风险,"克里斯蒂安补充道。 "一个著名的例子是法国大革命: 伦敦经济学院的玛丽亚 · 瓦丁格的论文表明，在法国各地，干旱和农作物歉收是1789年涌现的农民起义的导火索。更现代一些的例子则是，印度的干旱在某种程度上导致了纳萨尔派叛军的暴力行为。"

Emperors, dictators, autocrats, and despots: you better start praying for rain.

皇帝、独裁者、独裁者和专制暴君：你最好开始祈祷雨水充沛。