What is Climate Change and How Does It Happen?

Climate change is caused by greenhouse gasses like carbon dioxide (CO²), methane (CH⁴), nitrous oxide, and others in the atmosphere. They are called "greenhouse gasses" because they trap and re-radiate heat, like the glass in a greenhouse. About half of the light energy reaching Earth's atmosphere passes through the air and clouds to the surface, and about 90% of this heat is absorbed by greenhouse gases and re-radiated. This causes the average temperature to rise, which is called global warming. The warming ocean also increases water vapor in the air, which is another greenhouse gas. Scientists prefer the term climate change, or global climate change, because it includes all the other effects of this, not just the warming. Because of humans, there are more of these greenhouse gasses, causing climate change. Before that, natural climate change was very slow, species were able to adapt, and it didn't cause as many of these effects. But some people think that this isn’t true, and there are many myths about climate change. Most of these myths say that we don’t have to do something to reduce it because it is not happening, not caused by humans, or not very bad.

Myth #1: "The Temperature isn't Rising" or “It’s Cooling”

Some people say that the Earth is not warming, or even that it is cooling. Firstly, there are many measurements that show that Earth is warming. For example, one of the temperature anomaly graphs to the right shows temperatures from four different research centers. They are all very similar, and they all show that the overall trend is going up. Secondly, some people who say Earth is cooling show very small parts of the graph. If you look at the two temperature anomalies on the right side of the next page, it is easy to pick out an interval of time where it is cooling and say that global warming is not happening. It is also easy to find intervals that are warming. This is called the cherry picking fallacy, where someone only shows information that supports their opinion instead of showing the whole picture. What matters is the trend over many years, which is going up. Also, some places are warming faster than others and some years can be outliers because of variations, like El Niño and La Niña. For example, in the years after 1998, people were saying that global warming slowed and even stopped. 1998 was a warmer outlier because of El Niño, so the years after were cooler.

Myth #2:"Changes in the Sun are the Cause of Global Warming"

Some people think that we can't reduce climate change because the sun is causing it, but satellite data says that this is wrong. Since 1978, satellites have measured the sun’s energy. Changes in the sun and Earth’s orbit cause changes in the climate, but recent climate change is happening too fast to be caused by the sun. Since the 1980s, the 11-year average of solar irradiance and climate change have been going in opposite directions. Also, if it was the sun, the entire atmosphere would heat up. Instead, the troposphere (the lowest layer) is warming, but the stratosphere (the second layer) is cooling. This means that changes in the sun are not the cause of global warming.

Myth #3: “It isn’t Bad” or,“Climate Change Doesn't Affect Us”

Another myth is that climate change does not affect us, or that it is even positive. It is true that global warming has some benefits. Melting ice gives ships more pathways, and some warmer temperatures will reduce the number of deaths from cold and help crops. But global warming causes the sea level to rise, because of the melting ice and because warmer water expands. Warmer air also has more energy. Both of these cause stronger storms. Global warming also causes droughts and heatwaves because of the higher temperatures, and both the heat and the droughts will strengthen wildfires. It also causes more rainfall in some areas, and less in others, causing floods and droughts. The negative effects outweigh the positive ones.

Myth #4:"It's Cold Outside, so Climate Change isn’t Happening" or "Two Degrees is so Little"

Some people think that climate change isn't happening because it is cold outside, or they think that a two-degree change is not enough to make a big difference. Both of these myths aren’t true because this 2°C change is a change in the average temperature over many years. Even the average temperature over a whole year, or even a few years can be more or less. But the overall trend is still going up. You will see this if you look at a temperature graph, like those to the right. So, even though there are still cold days, there are still snowstorms, and even a whole year could be colder, that doesn't mean that climate change isn't real. This also means that a 2°C change will make a bigger difference.

Myth #5: "Volcanoes are the Cause of Global Warming"

One myth is that climate change is caused by the carbon dioxide (CO²) that volcanoes release. But people release much more carbon dioxide than volcanoes. Humans release the amount of carbon dioxide in an eruption of Mount St. Helens around every 2.5 hours and Mount Pinatubo twice daily! Also, a large volcanic eruption will cause changes all around the globe, but these effects will last for 1-2 years. Human-caused climate change keeps going up, even when there are no eruptions.

Myth #6: "Animals and Plants can Adapt to Climate Change"

Another myth about climate change is that animals, plants, and other living things on Earth can adapt to it. The Earth's climate is always changing. This natural climate change is slow enough that species can adapt to it. But they can't adapt to man-made climate change because it is going too fast for them to adapt. When there was no man-made climate change (only natural climate change), a change of a few degrees Fahrenheit would take thousands of years. Man-made climate change made a change of 1-2 degrees Fahrenheit in only about 100 years.