Earth’s Atmosphere: A Thin Blue Line, Not an Endless Dumping Ground for Carbon Pollution

By Tom Yulsman | June 2, 2014 5:18 pm
thin blue line atmosphere

The moon seems to float atop the thin blue line of Earth’s atmosphere in this photo taken on July 20, 2006 over the South China Sea by an astronaut aboard the International Space Stations. Blue light is scattered by atmospheric gases more than other wavelengths of light, thus giving the atmosphere a blue halo. (Please see other ‘thin blue line’ images in the gallery below. Source: NASA)

As debate over regulations proposed by the Obama Administration today to reduce emissions of heat-trapping carbon dioxide inevitably becomes shrill, you might keep in mind the image above, and six others in the gallery below.

They dramatize an important fact: Our atmosphere is not an endless dumping ground. In fact, when seen from the vantage of space, it looks like not much more than a thin blue line.

By 2030, the proposed regulations would cut carbon emissions from U.S. power plants by 30 percent below 2005 levels. That cut would result in 2 billion fewer metric tons of carbon dioxide being dumped into the atmosphere each year — an amount equal to the emissions from powering more than half the homes in the United States.

But the ambitiousness of the plan depends quite a lot on how you look at it. U.S. carbon emissions have actually been declining without the proposed rules, and we’ve made a quite a lot of progress. In fact, as of 2013, energy-related emissions were already nearly 10 percent below 2005 levels, thanks to a switch from coal to natural gas for producing electricity, as well as gains in energy efficiency, increased use of renewable energy, and the Great Recession of 2007-2008.

I’ll have more to say about this in a post later in the week. But for now, I thought I’d take this visual approach (make sure to enlarge the images):


Thunderclouds Atmosphere and SunCrescent Moon Earth's Limb and AtmosphereClouds and Atmosphere from Space ShuttleClouds Atmosphere and MoonCrescent Moon and Earth's AtmosphereNoctilucent Clouds Earth's Limb and AtmosphereSunset from Space Shuttle Columbia and Atmosphere

I think you’ll agree that the images are stunning in their own right. But I think they also can help us wrap our minds and hearts around a salient point: In a relatively brief period of time, we humans have managed to fundamentally alter the chemistry of one of our planetary life support systems: the Earth’s atmosphere. In so doing, we’re running increasing risks from climate change.

atmosphere blue line

Source: U.S. EIA

So, just how big a step forward is the Obama Administration proposing to take? How much of a difference will it make to the atmosphere? More about that in a day or so.

But for a preview, click on the thumbnail at right from the U.S. Energy Information Administration. It shows projections for world energy-related carbon dioxide emissions out to 2040, for the developed nations (OECD) and still developing nations (non-OECD).

We still have a lot of work to do.



ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


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