ABC News

NATURE’S EDGE NOTEBOOK

Observation, Analysis, Reflection, New Questions

By Bill Blakemore

The emissions of heat-trapping greenhouse gas that are now rapidly warming the earth are by definition invisible.

But what if we could see them? Might the United States have begun to regulate them long ago — as with other emissions we do see?

The Graphics Department of ABC News, working with technicians from the FLIR camera company, whose special “GasfinderIR – GF” cameras can “see” greenhouse gases, has created artist’s impressions of what it might look like if we could see our greenhouse gas emissions.

Take a look at this brief video of their work:

Greenhouse gases are invisible by definition because, in order to produce the “greenhouse effect” of building up extra heat inside, they must first allow that heat — which comes from the sun — to enter.

So, like the clear panes of glass on a greenhouse, the invisible greenhouse gases in the air let the hot, visible sunlight pass through them on its way down to warm the earth.

Look up from inside a greenhouse and you don’t see the glass — it’s invisible — but do see the bright sun behind it. You also feel its heat even though that light has passed through the glass.

On a greenhouse, that same invisible glass also traps much of that heat from the sun inside the greenhouse,  just as the invisible greenhouse gases in the air let in the visible light but also trap much of the heat from the sun.

That’s why they are called “Greenhouse Gases.”

But the analogy ends there.

The glass traps the heat simply by blocking the currents of sun-heated air so they don’t escape the greenhouse, whereas greenhouse gases trap the sun’s heat near the earth in a different way.

It has to do with a second invisibility.

The ‘Two Invisibilities’ of the Greenhouse Effect

The first invisibility of the greenhouse effect is that we don’t see greenhouse gases because they let hot visible light pass through them.

The second invisibility is that those same gases (such as CO2 and methane) have molecules shaped in such a way that, although they let hot visible light pass through them, they don’t give a pass to the hot invisible light called infra-red light.

Instead, they block, absorb and then re-radiate it.

Where does this hot invisible light come from?

A lot of that hot infra-red light comes up from a sun-warmed earth.

Heated objects naturally give off infra-red light. It has a longer wavelength that human eyes cannot see, though some snakes, mosquitoes and other creatures can.

(It is what some “night vision” binoculars and cameras are able to detect.)

When hot sunlight, allowed in from outer space by all the invisible gases in the air, strikes the earth, it warms it and everything else it hits — all of which, because they are now warmer, radiate more hot (and invisible)  infra-red light back up toward the sky.

There, this infra-red light bumps into the same sort of greenhouse gas molecules that, even a split second before, might have let it in from the sun when its energy was still in the form of visible light.

“Not so fast!” say the invisible (to us) greenhouse gas molecules to the hot and invisible (to us) infra-red light.

They absorb the infra-red light, which warms them up, and so they, in turn,  re-radiate that warmth (again as infra-red light) back out in all directions — not only upwards towards outer space but also sideways into the air and back down toward the earth, where it continues to warm whatever else it may hit and get absorbed by, including the land and plants as well as the winds and waters that constantly swirl all over the earth.

Ancient Climate Cycles Are Why Scientists Are Frightened

Of course, there has been some greenhouse gas in the air, warming the earth, ever since life began … and, indeed, helping make life possible.

And of course, climate change has always cycled up and down through the eons for various reasons, which is precisely why the world’s climate scientists are so frightened.

They tell us that by burning ancient buried carbon (coal, oil and gas), which puts powerful invisible greenhouse gas CO2 (carbon dioxide) back up in the air, we are beginning to kick-start yet another natural warming cycle, but at a speed so unnaturally fast that civilization’s basic economies and water and food supplies are already under great stress.

FLIR (for ‘Forward Looking Infra-Red’)

Here’s where the FLIR camera company’s “GasfinderIR – GF” cameras come in.

They are tuned to “see” various kinds of the invisible greenhouse gases that leak from hoses and storage tanks and are emitted from exhaust pipes and chimneys.

Actually, these cameras are tuned to detect the invisible (to us) infra-red light that bounces towards us off of most everything. Since that invisible light gets blocked on the way to the camera by the invisible (to us) greenhouse gas emissions, an image of those emissions appears against the background of whatever is behind them, from the camera’s point of view.

If we looked at the same scene with our eyes, we would see neither the infra-red light coming from most everything, nor the greenhouse gas emissions blocking some of it from reaching us.

You can take a look through some FLIR GasfinderIR cameras in this short video segment — see some things your merely human eyes cannot:

If seeing is believing, then obviously not seeing can make it easier to avoid believing – just as the fact we can’t see (nor feel) the earth spin on its axis meant that it took awhile after Copernicus and Galileo before most people believed that the sun only appears to set.

A growing number of middle school students can now explain all of the above. Sometimes their explanations even use animated graphics they find on those futuristic electronic pocket gadgets they’re often fiddling with.