The world is in the middle of an environmental crisis.

The first step to solving this crisis is to understand the science explaining it.

Climate change, Global warming, The greenhouse effect: You hear these terms a lot, but what do they mean? Are they the same thing? Do they somehow relate to each other? If you are wondering about this, you are not alone. And you might be surprised to learn that the science is actually fairly simple. The real issue is there are several pieces that need to be brought together.

Understanding global warming and climate change starts with the molecules that make air. Air is a mixture of gas molecules. The main gas molecules in that mixture are nitrogen and oxygen. The air has other gas molecules in much lower concentrations including, argon, carbon dioxide, neon, water vapor, methane, and nitrous oxide. But even in low concentrations, the air contains a huge number of these molecules.

1 liter of dry air contains 25,000,000,000,000,000,000,000 molecules
Type of gas molecule The number in 1 liter of dry air
Carbon dioxide 10,075,000,000,000,000,000
Methane 46,075,000,000,000,000
Nitrous oxide 8,250,000,000,000,000

Though the gas molecules carbon dioxide, water vapor, methane, and nitrous oxide might be in air in low concentrations, they have a big effect. These molecules, called greenhouse gases, absorb (trap) energy from the sun and transfer this energy to air in the form of heat. The warming effect from these molecules is called the greenhouse effect. The greenhouse effect has been important for the evolution of life as we know it. Without the greenhouse effect the average temperature on Earth would be -18 oC (0 oF). At that temperature it would be so cold, that the water on Earth, including in the oceans, would freeze, and life as we know it would not exist. Greenhouse gases do not just keep the air warmer during the day, they continuously radiate heat, thus warming Earth even at night.

Illustrator: Alina Bachman

Trap, Absorb, Transfer:  You will see all three of these words used to describe how energy from the sun when it comes in contact with greenhouse gases warms the air. It can be confusing. These words are not synonyms. How can they be used interchangeably to explain something in science?

When energy waves from the sun come in contact with a greenhouse gas molecule, the bonds between the atoms of the molecule vibrates and transfers the sun’s energy, in the form of heat, to the air. In effect, this traps or absorbs energy from the sun that would escape into space if greenhouse gas molecules were not present. It can be thought of as heat absorption through vibration.  

The sun radiates the same amount of energy to Earth each year. The average global temperature is a result of the amount of heat energy absorbed by molecules less the amount that is reflected back into space. Greenhouse gases are the primary molecules that transfer heat energy from the sun. Fluctuations in the concentration of greenhouse gases in the air lead to fluctuations in the amount of the sun’s energy that is absorbed, therefore causing fluctuations of the average global temperature.

With the advent of the Industrial Revolution, over two hundred years ago the amount of greenhouse gases in the air began to increase. The Industrial Revolution was a period in human history when animal and human power was replaced by machines. Machines are powered by a chemical reaction called the combustion reaction. The combustion reaction takes gasoline, oil, or coal and combines with oxygen to make energy that powers the machines. In addition to energy, the combustion reaction releases greenhouse gases and water vapor.

Illustrator Alina Bachman

 Global warming can be thought of as a simple budgeting phenomenon where

more heat-trapping molecules in the air cause the average global temperature increase.

During the past two hundred years, people have come to increasingly rely on machines and machine-made goods and services. This has led to an increase in the amount of greenhouse gases in the air. More greenhouse gases mean that more of the sun’s energy is transferred as heat into the air. The increase in the amount of transferred heat is causing an increase in the average global temperature, though the increase is not uniform. This temperature increase is called global warming.

Map courtesy of NOAA
Illustrator: Alina Bachman


Global warming is causing climate change

Some of the confusion with understanding climate change and recognizing that it is happening now is that many people treat the terms “weather” and “climate” synonymously. The difference between weather and climate has to do with the amount of time each is measured. Weather is a short-term measurement, measured in hours and days. Climate is a long-term measurement, measured using weather data averages collected over 30 or more years.

Since the Industrial Revolution, there has been a long-term increase in the average global temperature which matches the increased concentration of greenhouse gases. While the increase in the global temperature might not seem like much at 0.94°C (1.69°F), it must be remembered that this is an increase in the long-term average.

Graph Courtesy of NOAA

The increase in temperature is an average across the globe. Average long-term temperatures have increased by more than this in some areas, notably the polar regions, and less in equatorial areas. Global temperature is not the only thing affected. Earth is experiencing an increased incidence in powerful storms, rising sea levels, and changing ocean chemistry to the detriment of many ocean organisms.

Earth is 4.56 billion years old. Over its long history, the climate has changed many times. So why is it a big deal now? What is different about the current climate change is the rate at which it is occurring and the fact that one species, humans, is causing climate change. The rate the climate is changing is outpacing the rate of evolution for many species. The evolution of new traits takes time. Under stressful conditions, such as rapid climate change, those species that need more time to adapt are at risk of extinction. The rate of extinction is increasing as the rate of global warming and climate change increases. The current rate of extinction is happening so fast that scientists believe Earth is in the middle of the sixth documented mass extinction.

This doesn’t sound very hopeful does it? But don’t despair! Each of us can take some simple steps to slow the rate of global warming and climate change. The first and most important step is to understand what is happening and why. Next, use less energy from sources that generate greenhouse gases. In the short-term, you can help by reducing your energy consumption, such as using mass transit or driving energy-efficient cars (hybrids or electric vehicles), stop drinking bottled water and use reusable containers, change to energy efficient light bulbs, recycle, choose foods from near-by sources, and eat less meat. In the long-term, we need to end our dependence on the fuel sources that generate greenhouse gases: coal, gasoline, and oil. This can be accomplished by investing in and using alternative sources of energy.

One person or one country did not cause the current environmental crisis. Just like the warming causing climate change, this is a global problem. We need a global solution; with all of us working together to stop or slow the rate of global warming that is causing global climate change.

People are pretty smart.

If everyone came together, we could solve this problem.

Blair H Lee MS has been involved in science education for over two decades, first as a college professor and then as an author of science courses. She is an author for the critically acclaimed R.E.A.L. Science Odyssey. She is also the founder of Secular, Eclectic, Academic Homeschoolers.  Check out Blair’s new book The Science of Climate Change: A Hands-On Course for kids ages 9 to 15. The 92-page course weaves 18 hands-on activities throughout the straight-forward science-based explanations of global warming and climate change.

“The Science of Climate Change is a secular program containing peer reviewed, objective science. Even children who don’t yet consider themselves to be “good at” or engaged with science will be able to interact thoughtfully with the material presented here.”

      Rebecca Pickens, home|school|life magazine