You may have heard of global climate
change, which is often called "global warming." But how much do regular people understand the science of climate change? If you were asked to explain how global warming works, could you? Take a moment to try to explain to yourself how virtually all climate scientists think the Earth is warming. What is the physical or chemical
mechanism? In one study, we asked almost 300 adults
in the US– and not a single person could accurately explain the mechanism a global warming at a pretty basic level. Allow us to give you a short explanation
of how global warming works: First, here is how Earth's temperature works without considering how humans influence it: The Earth absorbs light from the sun, which is mostly visible light. To release that light-energy, Earth also emits light.
But because the Earth is cooler than the sun, it emits lower-energy, infrared light. So, Earth's surface essentially transforms
most to the visible light it gets from the sun into infrared light. Greenhouse gases in the atmosphere, such as methane and carbon dioxide, let visible light passed through, but absorb infrared light– causing the atmosphere to retain heat. This energy can be absorbed and emitted by the atmosphere many times before it eventually returns to outer space. The added time this energy hangs around
has helped keep Earth warm enough to support life as we know it.
Without this greenhouse effect–caused by these greenhouse gases in the atmosphere– the Earth's average surface temperature
would be about 50 degrees Fahrenheit cooler, which is well below the freezing point
for ice! So, how have humans change things? Since the dawn of the industrial age,
around the year 1750, atmospheric carbon dioxide has increased
by 40%– and methane has almost tripled. These increases cause extra infrared light absorption, meaning an extra greenhouse effect, which has caused Earth to heat above its typical temperature range. In other words, energy that gets to Earth
has an even harder time leaving it, causing Earth's average temperature to
increase– thus producing global climate change. To wrap up, we'll quickly summarize the
mechanism of global climate change: Earth transform sunlight's visible energy into infrared light, and infrared energy leaves Earth slowly–because it's absorbed by greenhouse gases. As people produce more greenhouse gases, energy leaves Earth even more slowly– raising Earth's temperature even more than it has already gone up. That's how global warming happens! In these few minutes you've hopefully
become one of the few people who understand the mechanism of global
climate change. Please share this video with others so
you can help them understand how global warming works, too.