A Brief Climate Change Study Guide
Foundational Points and Key Questions
“If the world pollution situation is not critical at the moment, it is as certain as anything can be, that the situation will become increasingly intolerable within a very short time … If we fail to cope with this challenge, all the other problems will pale into insignificance.”
The Duke of Edinburgh made the quote above over fifty years ago. At the time, the reaction to his speech was likely boredom, and he probably did not imagine the vitriolic and politically polarized debate that occurs today. Now, the public discussion is a clash of scientists and rational people versus grossly misinformed people and purposeful misinformers.
Perhaps you have already formed a strong opinion about climate change. Yet due to the counterproductive nature of the current public debate, you might be surprised about the facts when analyzed from a purely logical point of view. So, this issue of Essential Issues gives a very basic study guide to the key issues.
How do you separate out all of these competing views? You could just follow the person you trust more, but alternately you could also apply logical principles to evaluate the knowledge claims on your own. Using my experience from the inaugural Harvard Climate Boot Camp, I’ll outline the key knowledge claims around climate change and how you could look at verifying them.
What is Climate Change?
First, we need clarity on definitions. Climate change—often used interchangeably with global warming—refers to significant, long-term changes in Earth's climate patterns, particularly in the average temperature and weather conditions over the last several decades. As we will discuss further, the concern is that these changes are threatening the quality and sustainability of human life.
What is Global Warming?
Global warming refers to the recent significant rise in global temperature that is considered a driving factor in climate change. The global temperature measures the average temperature of the Earth's surface over a specified period, typically in degrees Celsius (°C) or degrees Fahrenheit (°F). This measurement reflects the overall heat content of the Earth's atmosphere and surface and provides information about the Earth's climate. See the graph below of the overall global temperature for the last few million years.
There are a couple of observations to note here:
The global temperature is not really a single reading of a thermometer. Rather, it is really an average of many sub-climates measured in a lot of different ways. Thus, every point on the globe is not rising and falling together. Some sub-climates might be going down while others go up. This does not invalidate the knowledge claim that the overall global temperature is rising.
You could ask, “How do we know what the temperature was a million years ago? There were no thermometers.” That is a good question, and the answer involves some sophisticated analysis of ice cores, naturally occurring isotopes and fossilized remains.
Also note from the graph that the global temperature is always rising and falling—in fact, millions of years ago it was much hotter than now!
Given that last bullet, you might be wondering: “Whoa, maybe the current temperature rise is just part of the natural rise and fall.” But notice the yellow-shaded Area of Anomaly on the far right edge of the graph. Since the timeline in the graph above is very long and doesn’t even have a uniform time scale, we need to zoom in on the current Holocene era to get a better picture of the situation. So let’s look at this graph by RealClimate.org.
In the graph, you can see that there was cooling until fairly recently, followed by a quite dramatic rise up to now. This is also shown in the graph by NASA below, which covers the change in temperature since 1880. The graph shows a very significant and consistent rise in temperature starting from around the 1970s.
Stefan from RealClimate.org summarizes it this way:
The well-known transition from the relatively warm Medieval into the “little ice age” turns out to be part of a much longer-term cooling, which ended abruptly with the rapid warming of the 20th Century. Within a hundred years, the cooling of the previous 5000 years was undone.
Refuting this finding would require you to challenge whether modern temperature recording is accurate or not. This would be extremely difficult because the current global temperature is derived from a multitude of independent weather stations, ocean buoys, satellites, and other technology that is monitored by thousands of independent scientists. This creates tremendous corroboration.
Is it Man-Made?
The big question is whether the temperature rise is natural—and thus not subject to control—or man-made and thus possibly manageable by regulating human activity. But, beyond the clear timeline overlap of the increase in human industrial activity and the temperature rise, the magnitude of the rise is far greater than can be explained by any other causes. As CalTech summarizes:
Earth's climate has changed throughout history. In the past 650,000 years, there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 11,700 years ago marking the beginning of the modern climate era—and of human civilization. Most of these climate changes are attributed to very small variations in Earth's orbit that alter the amount of energy our planet receives from the sun. But the warming we've seen over the past few decades is too rapid to be linked to changes in Earth's orbit and too large to be caused by solar activity.
Refuting this knowledge claim would require positing some alternative explanation for the dramatic rise in temperature. No such explanation presently exists.
Human Activity and Its Contribution to Climate Change
The human influence on climate change is also corroborated by analysis of human industrial activity and our understanding of how the Earth’s climate operates. The primary dynamic at play is the greenhouse effect, which is a natural phenomenon that is critical to regulating Earth's temperature. The way it works is that heat and certain gases are trapped in the Earth’s atmosphere rather than being radiated into space. This trapped heat has historically maintained an equilibrium that supports a relatively stable and habitable climate on Earth.
Using measurements of waste and greenhouse gases going into the atmosphere, we can confirm that currently excessive heat and gases are being trapped in the atmosphere. Consequently, too much heat is radiating back to Earth, heating the Earth more, and subsequently generating even more greenhouse gases. This creates a positive feedback loop that feeds on itself.
Writing for The Guardian, Katherin McVeigh gives an example of what is happening with the global sea level. She recounts experts who report,
Rising seas are one of the most severe consequences of a heating climate that are already being felt…Since the 1880s, mean sea level globally has already risen by 16cm to 21cm (6-8in). Half of that rise has happened over the past three decades.
The rising temperature of the surface of the oceans produces more water vapor, thus accelerating the greenhouse effect. This higher warmth on the surface of the ocean is now sinking deeper into the oceans, creating a condition that will likely take centuries to reverse. This is because “the systems causing sea level rise – specifically, the thermal expansion of the ocean and the melting of glaciers and ice sheets due to global heating – have a centuries-long time lag.”
Broken down further, the main factors contributing to global warming are:
Burning Fossil Fuels: The combustion of fossil fuels, such as coal, oil, and natural gas, for energy production, transportation, and industrial processes, releases large quantities of carbon dioxide (CO2) and other greenhouse gases into the atmosphere. These gases trap heat from the sun, leading to a rise in global temperatures.
Deforestation: The clearing of forests for agriculture, urban development, and other purposes reduces the planet's ability to absorb CO2 from the atmosphere. Forests act as "carbon sinks," and their removal increases the concentration of greenhouse gases.
Agriculture: Agricultural practices, such as the use of synthetic fertilizers and livestock farming, produce methane (CH4), a potent greenhouse gas. Additionally, deforestation for agriculture exacerbates the problem.
Industrial Processes: Certain industrial activities release greenhouse gases, such as nitrous oxide (N2O) and hydrofluorocarbons (HFCs), which contribute to global warming.
Waste Management: Landfills and waste management processes produce methane emissions as organic waste decomposes.
Land Use Changes: Urbanization, land-use changes, and the alteration of natural landscapes can contribute to localized warming and altered climate patterns.
Transportation: The burning of gasoline and diesel fuels in vehicles is a significant source of CO2 emissions. Air travel also contributes to emissions of greenhouse gases.
Energy Production: The generation of electricity and heat from fossil fuels, as well as emissions from power plants, contributes to greenhouse gas emissions.
Livestock and Agriculture: Livestock farming, especially cattle, produces methane during digestion, and the use of synthetic fertilizers releases nitrous oxide.
Waste Management: Landfills and waste management practices release methane when organic waste decomposes.
For a more graphical view that shows the relative contribution of the sources, we can check out this graph from the Brookings Institute.
The Effects of Climate Disruption
The climate changes from global warming are threatening the well-being of the global population and the sustainability of the ecosystem. Drawing from articles by the United Nations, NASA, and CalTech, the effects include the following:
Hotter temperatures. Temperatures are rising almost everywhere around the globe. This increases heat-related illness, makes it more difficult to work, and contributes to droughts.
More severe storms. More hurricanes and tornadoes create devasting flooding and landslides, which cause billions of dollars of damage.
Increased drought. Water is becoming scarcer, increasing dust storms and regions that are not suitable for life or agriculture. This results in famine and more fires.
A warmer, rising ocean. The ocean soaks up heat from global warming, which melts the polar ice caps and causes the water to rise. This warmer water is bad for sea life, and it causes flooding on the coasts, where most of the world’s population lives.
Loss of Species. According to The Global Species Initiative, over one-third of the Earth’s animal and plant species are projected to be extinct “by 2050 if current greenhouse gas emissions trajectories continue — a catastrophic loss that would irreversibly reduce biodiversity and alter both ecosystems and human societies across the globe.”
Poverty and displacement. The extended effect of this is putting more and more stress on human society. Some people are already displaced, such as in Central America and Madagascar. This increases the economic costs and creates not only human strife but desperation that may eventually lead to violence. See my article on the U.S. southern border surge for how climate change is a factor there.
What Can We Do?
The specter of climate change can seem overwhelming, but there are things individuals can do to help.
Be clear on what climate change is and its causes. Be sensitized to the misinformation that is being spewed frequently. Any new assertion must overcome the very solid knowledge claims made above. To make it easier to deal with counter-arguments, many common fallacies are nicely debunked by Skeptical Science.
Recognize this is not something that the market will handle on its own. States and countries need to act in the best interests of their citizens and the planet. Smart regulations, incentives, and governmental financial support are likely needed.
Personal choice is also important. Here is a list of ten things that the United Nations recommends we all consider doing if possible. But it’s not necessary to do everything at once. To make it even simpler, here is a simple approach offered by my friend Ashwani Kharuna, owner of the Karma Lakelands eco-resort in India. He recommends carrying these three items with you at all times:
A reusable water bottle to avoid using plastic
A cloth handkerchief to avoid a lot of tissues that go into trash dumps
A reusable bag to avoid using plastic bags
This article has briefly outlined the core assertions of climate change and what it means for us. I framed these foundational tenets and scientific conclusions for people who seriously want to consider what is happening. That said, it’s a complex topic that could take many directions, so please comment about questions you have or what you might want to read more about.
This a great piece, clear and concise. Thanks for reminding us of the little things we can do.