A Brief History of Climate Change

The following is a short essay on how the Earth’s climate has changed over the eons and what this has meant and will mean for life.

1. Greenhouse Gases:  The main greenhouse gases are carbon dioxide and methane. Water is also an important greenhouse gas, but it doesn’t build up in the atmosphere the way carbon dioxide and methane do, so it isn’t the problem that these other gases are.

Greenhouse gases get their name from greenhouses, which are glass structures that are used to grow plants when the weather is cold. The glass allows the sunlight to enter the greenhouse. When the light strikes a surface inside the greenhouse, it heats it up. Both heat and light are part of the electromagnetic spectrum but light has a higher frequency than heat. While the glass doesn’t stop the light from coming in, it does stop some of the heat from getting out, and that’s why a greenhouse can stay warm in cold weather. Greenhouse gases work the same way. They let the sunlight in but they block some of the heat from getting out, and this makes the Earth warmer.

2. The Atmosphere:  The atmosphere is mainly composed of nitrogen (79%) and Oxygen (20%). The other one percent consists of trace elements, which include the greenhouse gases. It takes only a tiny amount of greenhouse gases to keep the planet warm. For example, for every one million molecules of air, there are only about 4 molecules of carbon dioxide, which is the main greenhouse gas. If we didn’t have any greenhouse gases, the surface of the Earth would be solid ice from pole to pole. The trick is to have just the right amount of greenhouse gases to keep the planet warm but not too warm.
3. Climate History:  The Earth’s climate has changed constantly since it was formed 4.5 billion years ago. When it was first formed, it was a ball of hot lava. As it cooled, the lava solidified into a crust. Volcanoes created the Earth’s first atmosphere which was mostly carbon dioxide, methane, and hydrogen sulfide. There was no oxygen. That didn’t appear for another two to three billion years. It was produced by bacteria that consumed carbon dioxide and emitted oxygen as a waste product. Once there was enough oxygen, bacteria and later animals, like us, that use oxygen, could evolve.

Large, multicellular animals only evolved 500 million years ago. This is just the most recent 10% of the time the Earth has been around. For the first 90% of its existence, the only life on Earth was bacteria. Since multicellular life evolved, there have been at least five mass extinctions that killed from 65% to 95% of all life on Earth. Each time, life recovered and new life forms evolved.

The temperature during the last 500 million years has varied significantly. At times it has been much warmer than today. Other times, the entire Earth was covered in ice for millions of years. Despite this, life has found a way to survive, but at a great price. Life adapts to its environment. When that environment changes, especially if it changes rapidly, it forces life to change, and that is usually a dreadfully painful process.

The stable climate we enjoy began about ten thousand years ago when the Earth emerged from an ice age that lasted 100,000 years. During that time there were glaciers two miles high that came as far south as New York City. With so much water locked up in ice, the oceans were 360 feet lower.  During this ice age, the average temperature of the Earth was only five degrees Celsius (ten degrees Fahrenheit) cooler than today. A small difference in the average surface temperature can make an enormous difference in the climate of the planet.

4. The Holocene:  Since the end of the last ice age ten thousand years ago, we have been living in what the Earth sciences call the Holocene Epoch. During this time the global temperature has not varied much. The global climate has been stable and relatively mild, and this allowed humans to develop agriculture which, in turn, made civilization possible.
5. The Industrial Revolution:  The Industrial Revolution began in England around 1750 when coal began to be burned to generate energy to provide power to do all the sorts of things we do in the modern world. Heat was used to provide steam to power all sorts of machinery, including trains. The first train was built in 1804 in England. Steam power allowed economies to grow faster, and as economies grew, so did the Earth’s population. It grew from one billion people in 1800 to two billion people in 1927. During that time, oil and natural gas were discovered and exploited to provide even more energy. Electricity was discovered and huge power plants were built to burn coal to produce it. The internal combustion engine was invented which burns distilled oil (gasoline). Agriculture became automated and much of the world’s population moved from the country to cities.

Economic development drove the increase in human population which increased the demand for energy which increased carbon dioxide emissions. The more energy we used, the faster the population grew. It was a feedback loop. Just twelve years ago, in 2010, the Earth’s human population was seven billion. Today it is eight billion. This growing population requires ever more energy to support it, and this energy comes from burning coal, oil, and natural gas. These are called fossil fuels because they come from the fossilized remains of trees that lived hundreds of millions of years ago. They have been under ground all this time. As they have been unearthed and burned, their carbon is once again being released into the atmosphere. This is in addition to the naturally occurring greenhouse gases, which the environment has, until now, kept in balance. The Earth is unable to absorb all this extra greenhouse gas, so it’s building up, and as it builds up, it’s making the planet warmer.

6. Overshooting: Since the beginning of the Industrial Revolution, the world economy has been based on endless growth. The problem with endless growth is that the Earth is finite, and so are its resources. Scientists and researchers have determined that for the past forty years we have been in a condition that is called “overshoot”. This means that we are using the Earth’s resources faster than they can be replenished and that we are producing waste products faster than the Earth can process them. The result is that we have been eroding the ability of the Earth to sustain, not just the human population, but life in general. We are in the process of destroying the environment on which we and other life forms on Earth depend for their survival. Every bit of energy we use today, every plastic bottle we toss into the trash, means a further degradation in the life of our children and grandchildren. We are living on borrowed time and, what is most unfair, it is these future generations that will pay the price.
7. The Crime: The problem of global warming first went viral in 1988 when the country’s premier climate scientist, James Hanson, spoke before Congress and warned us that, if we didn’t rapidly begin to scale back our production of greenhouse gases, the world climate would become hostile to our existence. Unfortunately, fossil fuel  companies – coal, oil, and gas conglomerates – realized that this would mean a reduction in their sales, revenue, and profits, and so they began a campaign of lies to persuade people that it was all overblown and that there was no great threat to humanity. They greased the palms of politicians with millions of dollars, and this corruption halted governments from taking any action to address the problem. In fact, today, the fossil fuel industry is the most highly subsidized of all businesses in the world. As a result, greenhouse gas emissions have continued to soar and we are now so deep into this problem that we cannot avoid catastrophic consequences.
8. The Consequences:  We are already seeing the consequences. The world’s glaciers are melting at rates never before seen. Storms are becoming more frequent and more violent. Droughts and floods are increasing in frequency and severity. Droughts are causing more and larger forest fires, and both droughts and floods are reducing food production. These problems, particularly in the tropics, are becoming so great that already over 20 million people have been displaced. By 2050 the number of climate migrants is expected to exceed one billion. Where will they go?  The dislocation of this many people will inevitably create social and political unrest at levels we have not yet experienced. The consequences of chaos on this scale will likely be a major cause of the climate casualties we can expect.
9. The Temperature:  In just the last sixty years the Earth’s average temperature has increased by one degree Celsius compared to the average for the past 10,000 years. Recall that it only took five degrees Celsius to take us from an ice age to the Holocene climate, and that change took thousands of years. We’ve pushed the needle by one fifth of that amount in relatively speaking the blink of an eye. And the rate of change is getting even faster. Climate scientists have advised us that, if we reach 1.5 degrees above the Holocene average, the consequences to our global climate will be very severe, and if we reach two degrees, it will be catastrophic. We are now on pace to reach 1.5 degrees around 2030 – that’s just eight years away – and, assuming we don’t reduce the amount of greenhouse gases we are producing, we will reach two degrees by or before 2050.
10. Emissions and Concentration:  Although both carbon dioxide and methane are significant greenhouse gases, since carbon dioxide is responsible for three quarters of global warming, it has been customary to just measure it. Every year the world emits another forty billion tons of carbon dioxide into the atmosphere. This has, of course, driven up the concentration of carbon dioxide in the atmosphere. You recall that the concentration of greenhouse gases is tiny. It is measured in parts per million (ppm). Throughout the Holocene, the concentration of carbon dioxide was 280 ppm. Today it is 415 ppm – an increase of almost 50%. It is this increase that is driving the temperature up. The noted climate scientist who spoke to Congress back in 1988, James Hanson, has calculated that, in order to avoid adverse climate consequences, we must keep the atmospheric concentration of carbon dioxide at or below 350 ppm. We are already 65 ppm above this. This represents half a trillion tons of carbon dioxide. We have no technology capable of removing this quantity of carbon dioxide in a meaningful timeframe.|
11. Renewable Energy:  We hear a lot about wind and solar as a replacement for fossil fuels. What few people realize, however, is that, even with the rapid development of these technologies over the past decade, they still produce only three percent of the world’s energy requirements. The problem is that wind and solar installations produce only a tiny fraction of the energy that a fossil fuel plant can produce, so you need a great many of them – millions, in fact – and that is just not feasible. Wind and solar also have their own environmental problems. They require vast amounts of energy to manufacture, thus increasing greenhouse gases, they have a shorter life than fossil fuel plants, and when they are decommissioned, they produce extraordinary amounts of toxic waste.
12. Nuclear Energy:  Traditional nuclear energy uses a technology called nuclear fission. Despite the fact that, overall, nuclear energy has the safest track record of any system of producing energy, a few high-profile accidents has scared the public into fearing them and, as a result, most countries have backed away from them. As the climate crisis continues to deteriorate, it is likely that the world will go back to building nuclear power plants, but even they will be unable to replace the energy produced by fossil fuel plants, which still generate about 80 percent of the world’s energy. Another experimental form of nuclear energy uses a technology called nuclear fusion, but despite the expenditure of billions of dollars over the past half century, this technology is still unproven and it remains uncertain whether it will ever prove feasible.

Conclusion: It is difficult to predict the future when faced with something as complex as global warming, however, the trend is clear. As long as we continue to burn fossil fuels, the world will continue to warm at an accelerating rate. Our past predictions have always understated what has eventually happened, so I think it is safe to say that, whatever we think will occur, it will be worse.

We face two major questions: (1) when will the world get serious about global warming and (2) what can we do about it?  We still haven’t gotten serious about it. We’re starting to, but even the Biden climate initiative, as positive a step that it is, falls far short of what is needed. And what is needed? The United Nations’ International Panel on Climate Change tells us that, in order to avoid a global catastrophe, we must reduce emissions by 50% by 2030 and eliminate them completely by 2050. There is no scenario in which this is remotely possible. Even the US Environmental Information Administration predicts that greenhouse gas emissions will increase by 2050.

We are in a situation not dissimilar to that of lemmings. Lemmings are small rodents that live in the subarctic and subsist on moss. Moss doesn’t grow as fast as grass, so, as the lemming population grows, it starts eating the moss faster than it can replenish itself. The result is overpopulation, migration, starvation, and population collapse until the moss can regrow. Then the lemming population begins to grow again and the cycle repeats itself every three to four years. If we now look at the human population, which is four times what it was just a hundred years ago, we have over-leveraged ourselves and are running out of moss. The result will, in all likelihood, be a dramatic reduction in the human population.