Title: |
Becoming Earth |
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Author: |
Ferris Jabr |
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Category: |
Non-fiction |
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Rating: |
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Date Reviewed: |
January 24, 2026 |
Scientists now estimate that there are so many microbes living in the Earth's crust that they comprise a significant percentage of the weight of the
entire biomass of living creatures on this planet. These microbes subsist on chemical reactions in the rock. Their slow metabolism creates minerals in the crust, such as granite.
These minerals are actually less dense than the rocks in the sea crust, which contain iron and magnesium, making the sea crust heavier than the continental rocks. The mineral rocks float higher on the mantle because they are
lighter than the ocean bottoms - this is how the continents formed. Prior to the mineralization created by these microbes, oceans covered the entire planet except for a few volcanic islands. The landmasses we walk
on were created by microbes.
At the end of the last ice age, the territories we now call Siberia and Canada were vast, cold, grassy steppes. These plains were populated by mammoths, mastodons,
wooly rhinoceros, camels and elk with antlers that spanned eighteen feet. These huge animals fed on the grass, and also eating any stands of trees that got started to grow. Because grass is light in
color, it has a high albedo, which means it reflects more sunlight back into space. (Polar caps, with blinding white icy sheets, obviously have the highest albedo.) Primitive man showed up and
slaughtered all the megafauna. Anywhere that humans settled, the big animals disappeared (except for Africa, where animals evolved with humans). The disappearance of the big animals meant that
the steppe changed from grassland into huge forests. These endless stands of conifers, with their dark needles, reflect less sunlight than grasslands. So even before the Industrial Revolution,
even before the invention of agriculture, humans had already modified the global environment.
Life originated in the oceans (or perhaps in the crustal rocks). Though the first microbes lived on chemical processes, eventually phytoplankton invented photosynthesis.
This miracle allowed captured sunlight, water and carbon dioxide to be converted in sugars and useful organic molecules. The photosynthesis process expelled oxygen molecules as a waste product.
Eventually, after untold millions of years, Earth's atmosphere had a 10% oxygen content. One result was the creation of the ozone layer, which subsequently protected the barren landscapes from deadly
cosmic rays. Life evolved on land, and land plants were far more efficient at photosynthesis, and the oxygen content in the atmosphere soared, reaching as high as 35% of the air. This amount of free
oxygen allowed huge insects to evolve. But it also enabled gigantic wildfires. When the oxygen percentage of the air is less than 16%, fires cannot burn.
Zooplankton feed on phytoplankton. Zooplankton need calcium carbonate to make their shells (as do coral, mollusks, and other marine life). Zooplankton are the base of
the entire oceanic food chain. Due to CO2 emissions being absorbed by the oceans, ocean waters have become 30% more acidic when compared to pre-Industrial Revolution waters. By the end of this century, due
to the increasing CO2 levels, ocean acidity is expected to be 100% than it was prior to the Industrial Revolution. Acidic waters dissolve the calcium carbonate, inhibiting creatures from growing their
protective shells. The effects on all marine life would be profound.
One chapter describes the wonders of kelp forests. Kelp, like terrestrial forests, captures a lot of carbon. One scheme is to grow huge amounts of kelp attached to
biodegradable buoys in the open ocean. After a certain amount of growth, the buoys would collapse, and the kelp would sink to the deep ocean depths, permanently removing carbon from the air and water.
Assuming no unforeseen complications of sinking tons of kelp, it would take an area of ocean equal to the size of Russia to be covered with these kelp farms in order to capture enough carbon to have
an effect on global warming.
The chapter on plastic waste in the ocean was sad and disturbing.
The Amazon Tall Tower Observatory (ATTO) - is a tower built in the pristine rainforest that stands 1066' high. It allows scientists to capture what happens in the atmosphere
above the rainforest. It turns out that the rainforest creates much of the rain by releasing tiny microbes, literally seeding the clouds. There is a microbe called Pseudomonas syringae whose shape
allows water molecules to readily form crystalline structures - ice. Water vapor in clouds typical forms into drops when it can condense around a bit of dirt or soot. The P. syringae wafted up into the
air seeds the clouds and causes more rain to fall. Scientists estimate that if the Amazon rainforest loses 20 to 25% of its size, it will cease to able to generate the rainstorms. Already 18% of the Amazon
has been deforested, mostly to create cattle ranches.
The world emits 36 billion tons of emissions each year. Jabr says we are on track for 3°C warming by the end of this century. Never in the history of the Earth has the environment
changed this rapidly; plants and animals cannot adapt to such rapid climate changes, it will lead to widespread extinctions and the loss of the environment that our civilization depends on. The next one
hundred years could be a terrifying ride for those of us who survive it.
I thought this was an excellent book. I learned about life and the feedback systems on Earth. The bit about microbes forming the continents was surprising. The long-term prognosis
for humanity's civilization surely looks doubtful, but every book I read these days predicts that.
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