Beam me up, Scotty: There's no intelligent life here

By Leigh Pomeroy

Suppose you're a visitor from another planet surveying Earth under a cloak of invisibility. From watching commercials on American morning TV, you conclude that this species is obsessed with (1) improbably-named medications for mostly rare diseases, (2) healthy cat foods and (3) luxury SUVs.

You wonder: So much for the first two, but what is so important about those behemoth vehicles?

You quickly observe that there is often only one human in these vehicles, so you do a quick calculation: Weight of the average American: 180 pounds. Weight of a Lincoln Navigator: almost 6,000 pounds (and it's not the heaviest SUV). Thus, each luxury SUV is three tons of metal, plastic and rubber moving one 180-pound human from its home to wherever. That's about 33 pounds of machinery for every pound of human.

You calculate that each luxury SUV gets about 17 miles per gallon of gasoline and that burning a gallon of gasoline releases about 20 pounds of carbon dioxide (plus lesser amounts of methane and nitrous oxide) into Earth's atmosphere. (You already know that, as greenhouse gases, methane is 30 times greater and nitrous oxide 300 times greater than carbon dioxide.)

Another quick calculation indicates that driving one of these SUVs 12,000 Earth miles per Earth year releases about seven tons of carbon dioxide into Earth's atmosphere. Further brain browsing reveals that approximately 290 million vehicles are registered in the so-called United States, of which 34 million are SUVs. Maybe one quarter of those are large SUVs — more if the human owner lives in places called "suburbs" or "flyover country."

So you calculate again: 34 million SUVs X 25 percent = 8.5 million luxury SUVs x 7 tons of carbon dioxide per SUV = 59.5 million tons of carbon dioxide released into Earth's atmosphere each year from these SUVs (and that doesn't include methane and nitrous oxide). Yikes!

Knowing quite well the imminent threat of a warming Earth climate from rising greenhouse gases, you scratch your head. That's when you pull out your communicator and signal to your companion in the spaceship above: "Beam me up, Scotty. There's no intelligent life here."

According to climate scientists, the Earth is in a 12,000-year-long "Goldilocks" climate era — not too hot, not too cold, just right. Homo sapiens, our present-day human species, has been around for 200,000 years, maybe longer. So why, suddenly, would human civilization erupt just about 10,000 years ago, leading to all our major innovations — agriculture, mining and the use of metals, cities, worldwide trade and, relatively recently, the use of fossil fuels to produce energy, then computerization and worldwide communication via the internet?

Because it has all happened in this Goldilocks climate era.

But we can't count on this. Earth's climate has varied greatly since the planet emerged from the Big Bang some 4.5 billion years ago. The atmosphere has gone from a combination of hydrogen sulfide, methane, and lots more carbon dioxide than today to the present mix of 78 percent nitrogen, 21 percent oxygen and only one percent of other gases, including water vapor.

Yet greenhouse gases, just a miniscule 0.05 percent, have an enormous effect on Earth's climate.

Think about your own body, which remains healthy due to very important balances. For example, we all know that iron is a key component to human health. Yet it makes up only 0.006 percent of human body weight. Too much results in disease, even death; too little, the same.

Earth's atmosphere works the same way. Too many greenhouse gases result in a hot Earth, including tropical polar regions, which has happened in the past; too few result in a frigid Earth as in the last Ice Age, which ended just 12,000 years ago.

Climate history, as determined by climate scientists, is replete with rapid climate change events, defined as a rapid rise or fall of seven or more degrees Fahrenheit in just a few years. The last abrupt rise occurred about 12,000 years ago — coincidentally ushering in our Goldilocks era.

While all the previous abrupt climate change events occurred due to various natural factors, the next one we could bring on ourselves.

Today we know the climate is changing and that human activities are causing that change. The question is: What are we going to do about it?

Perhaps Scotty might say to his Earth-visiting companion: Don't you want to stick around and see what happens?