Last updated 7.6.23
Global warming is a term used for the observed century-scale rise in the average temperature of the Earth's climate system and its related effects. Scientists are more than 95% certain that nearly all of global warming is caused by increasing concentrations of greenhouse gases (GHGs) and other human-caused emissions.
Within the earth's atmosphere, accumulating greenhouse gases like water vapor, carbon dioxide, methane, nitrous oxide, and ozone are the gases within the atmosphere that absorb and emit heat radiation. Increasing or decreasing amounts of greenhouse gases within the atmosphere act to either hold in or release more of the heat from the sun.
Our atmosphere is getting hotter, more turbulent, and more unpredictable because of the “boiling and churning” effect caused by the heat-trapping greenhouse gases within the upper layers of our atmosphere. With each increase of carbon, methane, or other greenhouse gas levels in the atmosphere, our local weather and global climate is further agitated, heated, and “boiled.”
Global warming is gauged by the increase in the average global temperature of the Earth. Along with our currently increasing average global temperature, some parts of the Earth may actually get colder while other parts get warmer—hence the idea of average global temperature. Greenhouse gas-caused atmospheric heating and agitation also increase the unpredictability of the weather and climate, and dramatically increase the severity, scale, and frequency of storms, droughts, wildfires, and extreme temperatures.
Global warming can reach levels of irreversibility, and increasing levels of global warming can eventually reach an extinction level where humanity and all life on earth will end.
Irreversible global warming and climate change means that we will not be able to get the dangerous levels of excess greenhouse gases (like carbon) out of our atmosphere and back down to a normal and human-safe pre-industrial level for hundreds to thousands of years. (As of July 2023, We are currently at the insane atmospheric carbon level of 420 ppm. We will soon enter the generally considered irreversible and second phase of runaway global heating sometime between 2025-2031. This is when we enter into the carbon 425-450 ppm range.)
In this book, irreversible global warming is defined as a continuum of increasing temperature that causes the global climate to rapidly change until those higher temperatures becomes irreversible on practical human time scales. The eventual temperature range associated with triggering and marking the beginning of the irreversible global warming processes is an increase in average global temperature of 2.2°-4° Celsius (4°-7.2° Fahrenheit) above preindustrial levels.
Extinction level global warming is defined in this book as temperatures exceeding preindustrial levels by 5-6° Celsius (9-10.8° Fahrenheit) or the extinction of all planetary life, or the eventual loss of our atmosphere. If our atmosphere is also lost, this is referred to as runaway global warming. The result would be similar to what is thought to have happened to Venus 4 billion years ago, resulting in a carbon-rich atmosphere and minimum surface temperatures of 462 °C.
The temperature levels described above for irreversible and extinction level global warming are not hard and rigid boundaries, but boundary ranges that describe the related consequences and their intensities within a certain level of global warming. These temperature boundary levels may be modified by future research. More about irreversible global warming and extinction-level global warming can come about because of complex interactions that will be explained fully in Chapter 4. Chapter 4 and Chapter 5 will set the foundation necessary to understand how we are already creating the conditions that will precipitate irreversible and extinction-level global warming if we keep going as we are now.
How long carbon dioxide remains in our atmosphere
Carbon dioxide is currently the most important greenhouse gas related to global warming. For the longest time, our scientists believed that once in the atmosphere, carbon dioxide remains there for about 100 years. New research shows that is not true. 75% of that carbon will not disappear for thousands of years. The other 25% stays forever. We are creating a serious global warming crisis that will last far longer than we ever thought possible.
"The lifetime of fossil fuel CO2 in the atmosphere is a few centuries, plus 25 percent that lasts essentially forever. The next time you fill your tank, reflect upon this...[the climatic impacts of releasing fossil fuel CO2 to the atmosphere will last longer than Stonehenge… Longer than time capsules, longer than nuclear waste, far longer than the age of human civilization so far." —“Carbon is forever,” Mason Inman
How carbon dioxide in our atmosphere is tracked
Atmospheric carbon from fossil fuel burning is the main human-caused factor in the escalating global warming we are experiencing now. The current level of carbon in our atmosphere is tracked using what is called the Keeling curve. The Keeling curve measures atmospheric carbon in parts per million (ppm).
Each year, many measurements are taken at Mauna Loa, Hawaii to determine the parts per million (ppm) of carbon in the atmosphere at that time. At the beginning of the Industrial Revolution around 1880, before we began fossil fuel burning, our atmospheric carbon ppm level was at about 270. Here is the current Keeling curve graph for where we are today:
Keeling Curve Monthly CO2 graph, via Show.earth
As you can see, we are not doing very well. In later chapters, you will learn what this exponentially rising carbon means to your future. You also will see other graphs that will show you how today’s atmospheric carbon levels compare to those of our near and far distant past (hundreds, thousands, hundreds of thousands, and millions of years ago).
No matter what you hear in the media, if the total carbon ppm level is not going down or carbon’s average ppm level per year is not falling or at least slowing its steep increase, we are not making any significant progress on resolving the escalating global warming emergency. Total atmospheric carbon and carbon’s average ppm level per year are the mostdependable measurements of our progress and a predictor of what will be happening with global warming and its many consequences.
From the new Climageddon book: