Title:

The Long Summer

Author:

Brian Fagan

Category:

Non Fiction

Rating:

Date Reviewed:

October 13, 2023

he Long Summer is a fascinating book. It was written in 2004, but it seems even more relevant now as the devastating effects of climate change become undeniable. In the first chapter, Fagan writes about the efforts of the Army Corps of engineers to control the course of the Mississippi river outside of New Orleans. He wrote: "The battle to control the river never ceases, for a breach upstream is always possible and the awesome power of flooding water can break out anywhere." Of course, Hurricane Katrina struck in 2005.

The Long Summer describes how climate fluctuations had huge impacts on human history. Starting with the end of the last ice age, temperature variations allowed humans to move into Europe and Asia, and then humans retreated again when temperatures cooled again and the ice sheets expanded. I was surprised to read how often the Atlantic ocean currents were disrupted, and what a major effect this had on European conditions - and how the warming ocean temperatures once again threaten the flow of the Great Conveyor which carries warm water to the shores of Europe.

Fagan says that one of the greatest inventions in history was the needle - because it allowed our ancestor to sew form fitting clothing so that humans could venture into cold environments - and ultimately spread throughout Europe and Asia, and subsequently cross the Bering Land bridge and conquer the Americas.

Fagan describes a huge lake of melted glacier water called Lake Agassiz that once existed in central Canada - it was much bigger than Lake Superior. All of this water was suddenly freed in an unimaginable torrent when an dam of glacial ice collapsed, abruptly releasing trillions of gallons of fresh water that carved the St. Lawrence Seaway in the violent rush to the sea.

Euxine Lake was fresh water lake below sea level with many early civilizations clustered around its shores. A land barrier eroded, allowing the waters of the Mediterranean Sea to pour into the basin in another devastating flood - the waters rapidly rose until a new sea was formed at sea level - this was the origin of the Black Sea. It is possible that this incredible flood gave rise to the stories of the great flood that appear in so many cultures, including the Biblical story of Noah's ark.

It was impressive to read how scientists learn all of these facts. They study ice cores, drill into lake bottoms and examine fossil records. They can check pollen counts, tree rings, and the air inside bubbles trapped in ice. One study looked at the rocks on the ocean floor - those rocks could only have been deposited in those locations if they floated there in melting icebergs, so the scientists can deduce when icebergs were present in which eras.

Fagan states the he doesn't think that the extinction of so much of the Earth's megafauna was caused by human hunting; he argues that rapid climate change caused so many species to disappear. But if climate fluctuations caused the big animals to vanish, then why didn't smaller animal species also go extinct? Why did megafauna that was isolated on islands away from humans survive for much longer? Yes, one mastodon would provide enough meat to feed a tribe for an entire year, but humans frequently kill for a number of reasons that have nothing to do with collecting food.

On page 24 of the paperback edition is a graph that shows how remarkably stable the Earth's average temperature has been for the last 8000 years. Yes, there have been droughts which led to the fall of many civilizations (such as the Mayans), but for most of recorded history, humans have enjoy an ideal climate that has allowed us to prosper. On page 25 is a graph that shows the temperature variation over the last 420,000 years - it shows how the concentration of CO2 in the atmosphere closely tracked the ice ages (there were 4 ice ages over that 420K span). At no point on that graph did the CO2 concentration exceed 320 parts per million. Yet today CO2 makes up 421 ppm - the implications of which are terrifying if you stop to think about it, especially after reading an entire book about how previous civilizations collapsed in the face of climate stresses.

I thought the last paragraph Fagan wrote in the book (remember, it was written in 2004) was especially haunting, so I am including it in its entirety here:

But if we've become a supertanker among human societies, it's an oddly inattentive one. Only a tiny fraction of the people on board are engaged with tending the engines. The rest are buying and selling goods among themselves, entertaining each other, or studying the sky or the hydrodynamics of the hull. Those on the bridge have no charts or weather forecasts and cannot even agree that they are needed; indeed the most powerful among them subscribe to a theory that says storms don't exist, or if they do, their effects are entirely benign, and the steepening swells and fleeing albatrosses can only be taken as a sign of divine favor. Few of those in command believe the gathering clouds have any relation to their fate or are concerned that there are lifeboats for only one in ten passengers. And no one dares to whisper in the helmsman's ear that he might consider turning the wheel.