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What Exactly Are Greenhouse Gases, Anyway?

We’re getting back to basics to answer one of the most foundational questions a person can have about our warming world: What exactly are greenhouse gases, anyway?


Here at Climate Reality, we sometimes need to take a step back.

You know how your good friend Dave can rattle off pre-season stats with the precision of a brain surgeon, always seems to win your fantasy football league, and can’t begin to understand why you’re still rooting for [insert “Your Team” here]? Well, we’re kind of the Dave of climate action.

We’re so in the thick of climate everything that we can forget the latest Intergovernmental Panel on Climate Change’s (IPCC) report isn’t exactly flying off the shelves, so to speak, like Michelle Obama’s memoir Becoming.

But every so often, a headline will pop up that brings us right back down to the very Earth we’re working so hard to protect.

Citing a survey done by Yale and George Mason universities, Vox declared last year, “Almost 90 percent of Americans don’t know there’s scientific consensus on global warming.” More recently, the Verge proclaimed: “About half of Americans don’t think climate change will affect them — here’s why.”

These headlines are far from an aberration and come as no surprise: amid near-constant partisan squabbles and a lack of uniform learning standards, climate change education is uneven at best – and woefully lacking at worst. It doesn’t help that it can also feel like such an overwhelming worry that many simply tune it out entirely.

So, that’s why we’re getting back to basics to answer one of the most foundational questions a person can have about our warming world: What exactly are greenhouse gases, anyway?

Well, they’re gases, Silly Billy

That’s right! They’re also largely naturally occurring. But they act a little differently than non-greenhouse gases like nitrogen, oxygen, and argon.

You see, according to Encyclopedia Britannica, greenhouse gases (GHG) like carbon dioxide (the main GHG driving climate change), include “any gas that has the property of absorbing infrared radiation (net heat energy) emitted from Earth’s surface and reradiating it back to Earth’s surface.”

Did you get all that? Some but not all? Same.

In more straightforward speak, here’s the gist: GHGs like CO2, methane, nitrous oxide, and ozone let sunlight in to heat the Earth’s surface but they don’t let all that heat energy back out. Think about it like the global equivalent of wrapping yourself up in a big blanket – or the way the glass walls and roof of an actual greenhouse let sunlight in during daylight hours and retain that warmth at night.

Actually, it’s exactly like that. Hence their name. Get it?

So they “trap” heat in the atmosphere?

Yes. And under normal circumstance, this is a great, necessary thing – and it’s exactly how the planet is built to work.

“Earth's surface warms up in the sunlight. At night, Earth's surface cools, releasing the heat back into the air,” NASA’s Climate Kids explains. “But some of the heat is trapped by the greenhouse gases in the atmosphere. That's what keeps our Earth a warm and cozy 59 degrees Fahrenheit, on average.”

This is known as the “greenhouse effect,” and without it the planet would be too cold to support life. NASA estimates that without naturally occurring GHGs, Earth's average temperature would be near 0 degrees Fahrenheit (a very chilly negative 18 degrees Celsius).


>> Learn more: What Is the Greenhouse Effect? <<

Well, what’s the problem then?

The concern with GHGs isn’t the gases themselves – at least not on their own. Like we mentioned, most are naturally occurring and their action to retain heat is imperative for life on Earth. The problem has to do with the amount of certain GHGs in our modern atmosphere.

Since the Industrial Revolution, our burning of fossil fuels for energy has emitted hundreds of billions of tons of heat-trapping CO2 into the atmosphere, where it stays for a very long time. More and more CO2 (and other GHGs) means more and more heat.

Unlike the naturally occurring CO2 that acts as part of the normal greenhouse-effect process, this added carbon and the extra heat are more than the Earth’s finely balanced systems can handle. At least without changing our climate and making storms more violent, oceans more acidic, and on and on.

With all the coal, oil, and gas being burned, it’s unsurprising then that CO2 levels as of 2017 (the most-recent complete year) stood at 405.0 parts per million (ppm), higher than at any point in at least the past 800,000 years.

If history is any guide here, that’s not good news for the Earth – or for us.

“The last time the atmospheric CO2 amounts were this high was more than 3 million years ago, when temperature was 2°–3°C (3.6°–5.4°F) higher than during the pre-industrial era, and sea level was 15–25 meters (50–80 feet) higher than today,” according to NOAA.

Remember the bottom line here: Burning fossil fuels creates GHGs, polluting the atmosphere. More GHGs equals more heat and more climate change. More dangerous storms. More terrible wildfires. More farms drying out. More diseases spreading further across the Earth. You get the picture.


What is Global Warming? feat. Katharine Hayhoe

So, what is global warming? This adorable animation makes it super simple.

Posted by Climate Reality on Saturday, June 4, 2016

What can I do?

Our movement is at a critical turning point in the fight for common-sense solutions to the climate crisis. The good news is, the power to make meaningful progress on climate is in our hands.

But it all starts with understanding what is happening to our planet.

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