The universe is approximately 13.8 billion years old. Earth was formed about 4.5 billion years ago. Life forms we are most familiar with began to evolve about 570 million years ago, and mammals about 200 million years ago. Man (homo sapiens) only came into existence about 200,000 years ago, and was nomadic, traveling around to hunt food until the relatively recent invention of farming about 12,000 years ago. So, in the overall geologic time frame of the earth, man has been on the planet for only 0.004% of earth’s history.
The invention of farming (also known as agrarian society) enabled man to end nomadic life and begin to grow the earth’s population. In 1900, just 114 years ago, the global population was 1.5 billion people. By the year 2000, the global population had quadrupled to 6 billion. This is an extraordinary jump in population size in a very short period of time. The discovery of fossil fuels, starting with coal in 1798, then oil and natural gas, was a key ingredient in making this growth possible. A gallon of gas has the equivalent of approximately 200 man-hours of labor in it, and this led to surplus food production, which in turn supported population growth.
While it is hard to imagine that actions we take locally by burning fossil fuels can impact the vast ecosystem of the planet, it turns out that the global ecosystem is delicately balanced. With the advent of NASA science satellites that can watch the entire earth continuously, we know that ocean currents, atmospheric currents and global weather are all interconnected and impacted by even slight changes in average ocean and air temperatures. The last ice age ended about 12,000 years ago, which just happened to be when man invented farming and human population slowly began growing. From then, and up until approximately 1850, the concentration of carbon in the atmosphere had been a very steady 280 ppm (parts per million). It turns out 280 ppm carbon for the better part of 12,000 years provided a very favorable climate for human beings to grow and thrive.
With the advent of fossil fuels in 1798, we began to take carbon that was locked up in the earth in the form of coal, oil and natural gas, and put it into the atmosphere. Beginning several decades ago, climate scientists became concerned that as we emitted more carbon into the atmosphere, and in the process raised the concentration above 280 ppm, we could create problems by warming the earth due to the heat-trapping effects of carbon-based gases (primarily CO2 and methane), referred to as the greenhouse gas effect. Recently, the atmospheric level of carbon exceeded 400 ppm, and is headed rapidly toward 450 ppm with no leveling off in sight. This change in the level of atmospheric carbon is unprecedented since modern man has been on the planet, and in fact was last seen 130,000 years ago when at 450 ppm, worldwide sea level was 19 feet higher than it is today. And as of today, there is no end in sight for increases in the atmospheric carbon level because worldwide we continue to emit carbon into the atmosphere at increasing rates.