Читать книгу Climate Change For Dummies - Elizabeth May - Страница 15

Earth has been around for about 5 billion years, starting as a ball of swirling gas and dust left over from the formation of the sun. In the first part of this very long time, the iron and silica that make up most of the planet separated — the hot heavy iron went down to the core and the lighter silicates came to the surface and cooled. Volcanoes belched material and gases up to the surface. Continents formed and move around on the surface of the planet. The Earth froze from pole to pole, heated, thawed, froze again. The mix of gases in the atmosphere changed as volcanoes and sun had their effects.

An overview of life on Earth

Life began and then ebbs and flows ensued:

 3½ billion years ago: Single-celled organisms and viruses appeared.

 2½ billion years ago: Photosynthesis began in bacteria; sunlight provided the energy to convert carbon to cellular growth and emit oxygen as waste.

 900 million years ago: The first multi-celled organisms appeared.

 450 to 600 million years ago: Life exploded, and plants and animals from the oceans began to colonize the land.

 250 million years ago: The first mass extinction happens — the survivors are the early dinosaurs and mammals.

 200 million years ago: Another mass extinction occurs — now the dinosaurs become dominant. At the same time, some little mammals become warm-blooded, with new abilities to live in varying climates.

 150 to 100 million years ago: The first birds and flowering plants appear; large dinosaurs coexist with four distinct groups of mammals.

 66 million years ago: An asteroid hits eastern Mexico, the cloud of dust and steam blocks the sun for years, plants die, and the dinosaurs (and all other animals weighing more than 55 pounds [25 kg]) go extinct.

 55 million years ago: Another mass extinction happens, this one perhaps caused by a rise in greenhouse gases, that make the atmosphere a more effective insulator and causes Earth to heat past the survival limits of many species. It’s a tough place to live, Earth. Nothing is certain.

 6 million years ago: The first humans appear.

Human beings have been around in the same basic form for 6 million of the 5 billion years of Earth, one-eighth of one percent of all that time. During that (short) time, humans survived ice ages and developed tools, agriculture, writing, states and governments, music, and art. The human population grew constantly but slowly, held within the limits of what Earth and natural processes could provide, at about 0.04 percent per year, from 10,000 BC to 1700 AD. By 1700 about 600 million people lived on Earth, rising to about 1 billion by 1800.

But then things changed. Between 1800 and 1928, the human population doubled to 2 billion. From then on, the rate of increase rose rapidly until about 1968 — and population went up to 2.5 billion, to 5 billion by 1987, and 7.7 billion by 2019. The rate of increase peaked in 1968 and has been decreasing ever since, but still the population is expected to rise to a maximum of about 11 billion by 2100.

So humans have come to dominate Earth as no other life form ever has. And it’s not just people — the animals that humans keep are now by far the largest part of the world’s total animal biomass (biomass is the total mass of living matter in a given area).

In addition to the rising population, humans learned in the early part of the 1800s how to use the energy stored in the Earth millions of years ago. It all came from those old plants that millions of years ago used energy from the sun to grow and make their carbon tissue. When the plants died, their tissues rotted and decomposed, and over millions of years were compressed into coal and oil.

Beginning to use fossil fuels

Black or brown coal, the compressed remains of ancient plants, is a wonderful source of high-density energy. It’s sometimes easy to find on the surface of the Earth, so it has been used for thousands of years for fuel (and humans had learned to make a sort of coal equivalent, charcoal, by heating wood without enough oxygen to actually burn). But most of the coal in the world is underground, not so easy to pick up and take home to the fire. People dug shallow mines to get the coal out, but often water would flood in and prevent further digging.

And then came the revolution, the start of what this book is about.

In the late 1700s and early 1800s, a Scottish engineer named James Watt made the first steam engines with high enough efficiency to be used to reliably pump water out of coal mines. So the coal provided the fuel to heat the water to make the steam to drive the engine to work the pump to get rid of the water to get at the coal, and the Industrial Revolution was launched.

With abundant coal, industrial applications became possible all over England. Engines made by Watts and others drove all sorts of processes, factories of all sorts, wool and cotton spinning, steam looms, steel mills, railroads and steamships: Coal powered England to become the first great industrial empire. The technology was then exported around the world, to Europe and the new states in America, and industrial output exploded.

With this new kind of industry, people began to be employed in large numbers in centralized locations. The move from the country to the cities accelerated. In the cities, coal was burned for heat, for hot water, and “coal gas” lit indoor and outdoor spaces. People worked longer hours of work and enjoyed evening entertainments in theaters and music halls.

But wait. There's still more.

The second Industrial Revolution begins

In 1859, oil was produced from a well in Pennsylvania, and the second Industrial Revolution began. Coal remained dominant for a long time, but the use of oil and its companion product methane gas (called natural gas to help with marketing) grew rapidly until the use of oil equaled coal by the 1950s and then displaced coal from most uses (except to make electricity and steel) by the 1970s. Oil is easier to handle than coal, produces more usable energy with less smoke and soot, and is just a better fuel source for railroads and ships, for industry, and for electrical generation. So King Coal lost its crown.

But humans were making more and more stuff and were still burning a lot of coal and now a lot of oil and gas as well. When that coal and oil was burned, humans got to use that ancient solar energy again to make things and move things and keep things warm. And all that carbon was released again, off into atmosphere as carbon dioxide and other gases called greenhouse gases because they act like the glass in a greenhouse to keep heat in. So, like any good greenhouse, the Earth became warmer. And it’s still getting warmer today. And that’s the problem to solve.