The Fate of Rome: Climate, Disease and the End of an Empire, Harper- B+

  How could Rome, seat of state for over a millennium and the wealthiest city ever, come to be sacked by the Goths in the year 410? History tells us of the acts of emperors, generals, consuls, and invaders, but the fate of Rome "was equally decided by bacteria and viruses, volcanoes and solar cycles." The empire, which had spread from Syria to Britain, created pathways for infectious diseases that significantly contributed to the decline and fall of Rome. Gibbon ordained that the 2nd century saw mankind at its most prosperous and happiest. The empire comprised 75 million people. The city itself exceeded a population of a million, a number not to be seen in the west again until 1800. The fall of Rome was "a monumental episode of state failure", characterized as "the single greatest regression in human history." Science now allows us to recognize changes in the climate in the past and affords us the opportunity to apply that knowledge to our understanding of history. 

Rome prospered at an extraordinarily positive time, known as the RCO, the Roman Climate Optimum. During the last two centuries BC and in the first century CE, the environment was perfect for economic and population growth. Temperatures were moderate and the amount of rainfall matched the needs of the times. However, Rome's luck turned early in the Christian Era and by the Dark Ages, the Mediterranean world faced the Little Ice Age. In 165, the world's first pandemic, known to history as the Antonine Plague,  attacked Rome from the east through the Red Sea and the Nile River Valley. All indications are that it was a smallpox virus. Estimates of population loss are difficult to calculate, but somewhere between 10-20% of the people in the empire, from the Red Sea to Hadrian's Wall, died. The city itself lost as many as 300,000 souls. The impact was catastrophic. Fiscal distress and the devastation of the legions put the empire in a defensive posture at its borders, from which it never recovered. A century later, the second half of the 3rd century saw a series of governance and security crises, with emperors ceaselessly usurping their predecessors and invasions on all fronts. Concurrently, a withering drought and another pandemic slashed the empire. An African drought reduced the Egyptian wheat harvest. The Plague of Cyprian struck the length and breadth of the empire, for possibly fifteen years. Some sort of viral hemorrhagic fever is the likely cause. The frontiers buckled in the 250's as Asia Minor and the Danube basin were lost. The Rhine followed. The empire was saved when the moneyed Mediterranean aristocracy was replaced by a long series of Danubian military officers known as the Theodosian Dynasty. The empire recovered and flourished for well over another century. The long 4th century saw the empire shift its focus to the east with the establishment of Constantinople. We have known for centuries that the Hun left the Asian steppes and forced the Goths out of the area north of the Black Sea and into the empire. What we now know is that there was a mega-drought in the steppes in 350-370. The Huns crossed the Volga and headed into Europe. Their ability to shoot arrows from fast-moving warhorses swept the Goths away. The Goths didn't so much invade the empire as they migrated into it. In the fifth century, the western half of the empire of Rome faded away. The empire prospered in the east, particularly in the 6th century reign of Justinian. He reorganized the bureaucracy, codified the empire's laws, recovered portions of Italy, made peace with the Persians and built Constantinople up to a population of 500,000. However, in 541, the bubonic plague made its entry into the empire. The ensuing two decades saw the empire barely able to collect taxes, feed the people or field an army. In the capital city, half of the population died in the summer of 542. The plague devastated Asia Minor and is believed to have spread as far west as Ireland. Plague endured into the next century and even made a singular appearance in Constantinople in 747. The persistenc of Y. pestis"strangled hopes of recovery." The final sequence of Rome's demise came in the 7th century when climate change, political disintegration and the rise of Islam swept west. Two volcanic eruptions in the 530's-540's led to the coldest decade in the last 2,000 years, adding incalculable stress to the Mediterranean world. The reduction in solar radiance led to a century and a half of the Late Antique Little Ice Age. There were droughts in the south and floods in the north. Environmental degradation slowly "sapped the vitality of the empire." The interconnectedness slipped away, and slowly a globalized prosperous, trading world became a localized simpler place. Most of the west's cities entered terminal decline. Rome's population was counted in the tens of thousands. Italy was reduced to a subsistence economy. In the east, the damage was not as significant, but even there, Constantinople could not field the armies it needed and more importantly, could not pay them. The coup de grace came from the Levant. Beginning in 636, and continuing for a century, the armies of Mohammad cleaved and forever severed the southern portion of the empire. From Arabia, through the Holy Land, Egypt and all of North Africa into Spain, the Muslims conquered. Not only was no semblance of the empire's structure left, but its religion was replaced. The dynamism and great zone of energy was lost. Byzantium was a rump state centered on its capital. The Latin west became Eurasia's backwater. 

I have found this a compelling read. I have long known that our species has moved from point A to point B because of the impact of the environment where it  lived. Our country's success is a function of the bounty of our continent. So to see a historian use the  recent tools of science to delve deeper into the world's history is extraordinarily enlightening. My only caution  to prospective readers is that this is as much science as it is history.