A Brief History of Climate Change

Climate change is as old as the history of the Earth. One of the foundation blocks of world literature, the Epic of Gilgamesh from ancient Mesopotamia (c. 2100 BCE), is a prime example. Its central character is King Gilgamesh, ruler of Uruk. As he seeks immortality, he meets the boatman Utnapishtim, who warns him that the gods are preparing a terrible flood: “Tear down thy house, build a ship; abandon wealth, seek after life; scorn possessions, save thy life. Bring up the seed of all kinds of living things into the ship which thou shalt build.” 

Written on tablets that date back to around 650 BCE the story has inspired many religions and belief systems: angering the gods provoked punishments that brought environmental consequences. The historian Peter Frankopan noted: “The ‘mandate of heaven’ that gave imperial rulers the authority and legitimacy to rule was in part linked to notions of morality – but was most bluntly manifested (or otherwise) by benign climate conditions.” 

Rulers who enjoyed divine favor were blessed with predictable rains and golden sunshine that allowed for bumper crops, while those out of favor were punished with violent storms or no rainfall at all. Frankopan speaks of “efforts to make sense of climatological shocks.” Of which there were many, as he notes in his latest book The Earth Transformed, a retelling of human history along climatological and environmental disasters. The examples are numerous. 

More than 4,000 years ago in Mesopotamia – the area today made up of Iraq, northeast Syria and southeast Türkiye – the Akkadian Empire became known as the first empire in history. It reached its peak between the 24th and 22nd centuries BCE. It boasted all the trappings of an advanced civilization with a governmental system, urbanization, a diversified economy and records in cuneiform, a logo-syllabic writing system. 

It was in this writing system that the Epic of Gilgamesh tells one of the most famous natural disaster stories in human history: a great and ancient flood, which can also be found in many world religions. Yet it wasn’t a flood that led to the downfall of the Akkadian Empire. Despite its high level of development, it collapsed rather abruptly and without foreign influence. 

Scholars attribute the demise to a sudden change in climate patterns across the region, with rapidly increasing aridity and a once-in-a-century drought. The archaeologist Harvey Weiss writes: “After four centuries of urban life, this abrupt climatic change evidently caused abandonment, regional desertion and the collapse of the Akkadian Empire. Synchronous collapse in adjacent regions suggests that the impact of the abrupt climatic change was extensive.” 

More climate and environmental seismic changes, both literal and figurative, fill the history books. The eruption of Mount Vesuvius in 79 CE, when the Roman Empire was in its heyday, destroyed Pompeii, Herculaneum and other sites and released so much ash “that some of it reached Africa and Syria and Egypt, filling the air overhead and darkening the sun,” as the writer and eyewitness Pliny the Younger reported. His uncle Pliny the Elder – who died at the scene while attempting a rescue mission – is the author of the 37-volume Natural History, testament to how much the interplay between civilization and nature already preoccupied the Romans. 

In later centuries, a deterioration of climatic conditions directly contributed to the fall of the superpower. As arguably the first global empire in history, the Romans connected societies by land and by sea as never before, with the unintended consequence that germs capable of causing pandemic events moved freely and at an unprecedented speed. The Antonine Plague (165 to 180 CE), brought to Rome by armies returning from Asia, was probably the global debut of the smallpox virus. Despite severe losses the empire recovered, but never regained its previous commanding dominance. 

Then, in the mid-third century, a mysterious affliction of unknown origin called the Plague of Cyprian (c. 249- 270) sent the empire into a tailspin. The historian Kyle Harper writes: “Humans shape nature – above all, the ecological conditions within which evolution plays out. But nature remains blind to our intentions, and other organisms and ecosystems do not obey our rules.” 

Rome was not the only great civilization that fell (at least partly) because of climate change. The Mayan civilization in Mesoamerica (comprising the modern day central to southern Mexico, Belize, Guatemala and parts of Costa Rica, El Salvador, Honduras and Nicaragua) lasted for some 3,000 years. Agriculture was the cornerstone, with great cities being built as the population grew. Religion was an important part of Mayan life, with sacrifice a regular ritual to appease and nourish the gods and keep the land fertile. 

However, sometime around 900 CE things started to go wrong. Overpopulation put a massive strain on resources. The consequence was increased competition, which led to violent conflict over scarce resources. An extensive period of drought that ruined crops and cut off water supplies led to the fall of this ancient civilization: Within a couple of generations, swaths of central Mayan lands were all but abandoned. 

Another example comes from Southeast Asia. The iconic Angkor Wat temple complex was built in the early 12th century CE in the capital of the Khmer Empire, first as its state temple and later as a mausoleum. The kingdom reached its greatest territorial extent under King Jayavarman VII who defeated the Chams and conquered large parts of their territory (in what is now central and southern Viet Nam). But only a hundred years later the Khmer Empire was in a death spiral. What had happened? 

Though historians have identified a number of reasons (external threats, religious strife, internal destabilization), ecological failure and breakdown of infrastructure are seen as major catalysts. Periods of drought led to decreases in agricultural productivity and monsoon floods damaged the water infrastructure. To adapt to the growing population, trees were cut down to clear space for more rice fields. That created rain runoff carrying sediment to the canal network and damaged the system until it became inoperable. 

Climate change also had its hand in developments on the other side of the world: In Greenland, an island in the far North Atlantic, some 5,000 Viking settlers lived for around 500 years until the “Little Ice Age” during the early 15th century disrupted their lives. Temperatures dropped, reducing substantially the productivity of farms and making it harder to raise livestock. When attempts to use the sea as a source of food failed, the Norsemen eventually had to abandon their colony. 

The natural cycle of climate change is an ongoing and unavoidable part of life. When the Earth was created some 5 billion years ago the young sun was shining 30 percent weaker than it does today, writes the climatologist Dirk Notz, University of Hamburg. Nevertheless, the infant Earth was sufficiently warm to allow the existence of liquid water. That changed about 650 million years ago, when the Earth was covered in ice for many millions of years. When volcanic eruptions led to the emission of greenhouse gases, the Earth was able to warm again: Some 100 million years ago, when the dinosaurs dominated the biosphere, the average global temperature was about 14°C higher than today. 

As climate change has always been a feature of the evolution of our planet, it is quite unusual that for the past 10,000 years climate conditions on Earth have been so stable. In fact, this stability was the precondition for the development of modern civilization: agriculture, settlements, trade, migration, communities. Professor Notz: “Regionally, changes in climate have most likely repeatedly contributed to the disappearance of ancient cultures, but globally the development was able to continue.” 

What is new – and today widely accepted – is the impact of humankind on climate change. Since the 1760 invention of the steam engine fired off the Industrial Revolution, ever-increasing amounts of polluting gases have been pumped into the atmosphere, triggering an unprecedented rate of warming. This has not gone unnoticed: Following scientific examinations of climate change by pioneering scientists, in 1824 the French physicist Joseph Fourier became the first to describe the Earth’s “greenhouse effect.” 

Industrialization and the triumph of the automobile, powered by the internal combustion engine, changed the world – and further increased the burning of fossil fuels: In 1927, carbon emissions from fossil fuel burning and industry reached 1 billion tonnes per year for the first time worldwide. Despite various efforts to reverse the trend it continues: In 2006, carbon emissions from the same sources reached 8 billion tonnes per year. 

The consequences are clear. The Intergovernmental Panel on Climate Change (IPCC) says: “Human activities have warmed the Earth’s climate by more than 1°C since the late 19th century, and the effects on our climate are unprecedented.” An increase of 1.5°C could put between 20 and 30 percent of animal species on the fast track to extinction. If the planet warms by an average of 2°C the consequences will include a devastating loss of coral reefs, loss of habitats for many insect species and more than a third of humanity exposed to extreme heat at least once every five years, according to the Australian Climate Council. Extreme weather events, floods and droughts will threaten millions with famine, massively increasing migratory pressures. 

These are stark warnings and the clock is ticking. Professor Notz notes: “Climate change and disease evolution have been the wild cards of human history.” The challenge humankind is now facing was captured by the Scottish writer Robert Louis Stevenson: “Life is not a matter of holding good cards, but of playing a poor hand well.” 

4,000 years of civilization and climate change 

2000 BCE - The Akkadian Empire 

The Epic of Gilgamesh, written around 2000 BCE, tells of a great and ancient flood – but scholars instead attribute the demise of the Akkadian Empire to a sudden change in climate patterns across the region, with rapidly increasing aridity and a once-in-a-century drought. 

79 CE - The Roman Empire 

The eruption of Mount Vesuvius in 79 CE destroyed Pompeii and Herculaneum. A study of tree rings published in the journal Science provides evidence of climate shifts in the region between 250 CE and 550 CE – likely contributing to the fall of the empire. 

900 CE - Mayan civilization 

Around 900 CE, drought and the resultant scarcity of food and water combined with overpopulation to doom this 3,000-year old civilization. 

1300 CE - The Khmer Empire 

In the early 13th century drought and flooding damaged the kingdom’s water infrastructure. This, along with widespread tree-felling, created rain runoff. Consequently, the build-up of sediment in the canal network eventually destroyed the system. 

1500 CE - Greenland’s Norse colony 

The “Little Ice Age” (1500–1850) had a big impact on Greenland’s settlers in the 15th century. As the climate cooled in the North Atlantic, attempts to use the sea as a source of food failed and the Norse colony was abandoned. 

1760 CE - The Industrial Revolution 

Since the invention of the steam engine in the 1760s and the spread of modern industrial processes across the globe, pollutant gases have had a profound warming effect on the Earth’s atmosphere.