Back in the 1970s, we heard that the population explosion was unstoppable, famine was inevitable, cancer from nuclear waste and chemicals would be epidemic, acid rain was killing the forests, and fossil fuel resources (oil, gas, and coal) were diminishing at an alarming rate.

Matt Ridley makes a case that none of this occurred. In his new book, The Rational Optimist, Ridley presents compelling evidence that things have been improving—for a couple of hundred years.

Ridley received a doctorate in zoology from Oxford University before pursuing a career in journalism. He has been the science editor for The Economist. He has written books on popular science that have sold more than 800,000 copies and been translated into 27 languages.

He takes on each doom-and-gloom scenario and shows what has actually been occurring and why. The main reason for improvement, he believes, has to do with trade, exchange, and specialization. In a simple example, he points to a stone-age hand ax, laboriously chiseled by early humans for almost a million years. He compares that with a computer mouse, almost the exact same size, which goes obsolete in about five years.

Any stone-age human had access to the knowledge needed to make a hand ax. But the knowledge to build a mouse rests not in one person but in thousands, perhaps millions, of people who make its parts. The plastic, rubber, silicon wafer chip, and metal come from many trades. So the making of the mouse is a product of what Ridley calls the "collective brain."

And this is humankind's signature accomplishment, he argues. Personal IQ doesn't amount to much. Rather, it is the accumulated knowledge of the culture that counts. That is because specialists get really expert at making one thing and then trade it for other things they need. Trade, Ridley tells us, is far, far older than farming.

Moreover, the "doom merchants" have consistently overlooked one important thing that the exchange of trade and ideas brings about: ingenuity and problem solving.

Famine. Population pressure and limited agricultural productivity suggested that by the early 1960s, India would face famine. But thanks to a new seed stock, the yield of India's wheat exploded. The 1968 crop was so large that there was no place to put it, so it was stored in schools. India is now an exporter of wheat and rice.

Since 1900, the population of the world has grown by 400 percent, cropland area has increased by 30 percent, average yields have gone up 400 percent and crop harvests by 600 percent, and per-capita food production is up by 50 percent. Why? New varieties, new uses of fertilizer, and better management of water resources such as drip irrigation.

Population. The population of the planet is growing, but at a decreasing rate. We are seeing a worldwide decline in the birth rate. Now nearly half the world has a birth rate that is lower than the replacement rate of 2.1 children per couple. It is now estimated that world population will peak at somewhat over 9 billion people in about 2050 and then start to decline.

Why? It seems that when infant mortality goes down, women tend to have fewer children. Urbanization means that a large family isn't needed to work the farm. Women's independence and education mean that family life improves.

Fuel. Coal made the industrial revolution possible. It came along just as England was running out of trees. Today, England is more forested than it was in 1700, when charcoal was needed to make iron and steel.

We will continue to need coal, especially for underdeveloped countries, but its use will decline. We will rely more on natural gas. The recent invention of a way to pull natural gas out of shale coal has resulted in an estimate that natural gas reserves in the United States will last 400 years. New nuclear power technology in the form of small pebble-bed thorium reactors is in development. This new type of reactor can be used in small cities, and its waste has a half-life of about 100 years (and is safe in just 50 years), instead of 50,000 years for uranium. The residue can't be made into bombs. And thorium is more plentiful and cheaper than uranium.

Climate change. Ridley offers evidence that extreme climate outcomes are unlikely. Part of this is undoubtedly due to the expected decline in coal as a primary source of electricity, and new technology for removing carbon dioxide from the atmosphere.

Conclusion. Yes, many people are still deeply mired in poverty and disease, there is cause for despair in parts of the world, and we will have additional natural disasters. But we now have an understanding of what it will take to bring about change for the better. And if you study Ridley's explanation of the nature of the "collective brain," you will be convinced that he is on to something important. Ridley suggests that an ongoing effort to maximize trade and the ever-increasing expansion of the collective brain will more than offset the challenges we must face. That is a reason for rejoicing.

This book dares us to be optimists, to consciously seek solutions to our problems and engage in worthwhile ventures. It's very readable, convincing, and refreshing.

---