Showing posts with label global warming. Show all posts
Showing posts with label global warming. Show all posts

Monday, August 15, 2011


When I was in college thirty years ago conservatives were making one of their regular attempts to discredit evolution. They called themselves "creationists" then, and their big "discovery" at that time was the laws of thermodynamics. The creationists said that evolution was impossible because the law of entropy forbade it. Entropy dictates that order will dissolve into disorder over time.

The problem with their argument was that they omitted key facts from the laws. Yes, order dissolves into disorder over time, in a closed system with no energy inputs. The earth, however, is not a closed system. It is an open system that constantly receives more than a kilowatt of solar energy per square meter.

It is this external solar input that provides that the energy for chemical and biological systems to grow and increase in complexity, and what makes evolution and life possible. This is not a violation of the laws of thermodynamics.

Well, the conservatives are back at it again. Weatherman Joe Bastardi was featured in a Fox News segment attempting to discredit global warming. He said, "It contradicts what we call the first law of thermodynamics. Energy can neither be created nor destroyed. So to look for input of energy into the atmosphere, you have to come from a foreign source. It's already out there, carbon dioxide being part of it."

He lapses there into incoherence. Global warming does not contradict the laws of thermodynamics: the sun constantly pumps energy into our atmosphere. In fact, we are alive today because of global warming -- without an atmosphere containing greenhouse gases like CO2 and water vapor, the average temperature of earth (the blackbody temperature) would be much colder, somewhere around 1 degree Celsius or colder, depending on the albedo of the surface.

To his credit, one of the interviewers chimed in, "Maybe the sun?" was the source of the energy causing global warming. But Bastardi just ignored this, going on to talk about Le Chateliler's principle, which he says is the tendency of a system in distress tries to return towards normal.

But this idea of "normal" doesn't work if you change the basic rules of the game by overloading the system beyond its capacity. It's true that if the concentration of CO2 increases some carbon sinks will absorb more. But those sinks have a finite capacity. The ocean, for example, loses its ability to absorb CO2 as temperature increases. And ocean temperatures and acidity are increasing.

Furthermore, if you actually read what the studies found, temperatures did in fact increase in the last 10 years, just not as fast as they did the 30 years before (the infamous decrease in the rate of increase). Why? Several reasons: aerosols injected into the stratosphere by relatively small volcanic eruptions which climate modelers did not consider have moderated the increases somewhat, and substantial increases in sulfur particles that Chinese coal plants have been emitting in greater and greater quantities have further cooled temperatures. But that sulfur doesn't stay in the air: it eventually comes down as acid rain. There was also some unaccounted-for heat exchanges with the ocean.

These are not really surprises: the reason scientists are so hesitant to state things in the categorical black-and-white mode that conservatives always want to hear, is that reality is complicated. Scientists don't know everything and don't pretend to. But the point is that these new results don't disprove global warming; it's still true that global temperature will go up in the next 50 years; just not at the same rate some models predicted. Any number of things could happen that could increase or decrease that change: volcanic eruptions that emit a lot of aerosols of the right composition could slow down the warming, but another eruption emitting a lot of CO2 could accelerate it. The key thing is that we know our actions will have a bad effect if nothing else changes, so the conservative thing to do is avoid causing serious problems.

But back to the reality of greenhouse warming, which conservatives seem to discount on a visceral level. Consider Mercury and Venus. Mercury is 58 million km from the sun. The mean temperature varies from about -70 C to +70 C, depending on latitude, with a low of about -200 C and a high of +400 C. Venus is 108 million km from the sun, more than twice as far. But its mean temperature -- pretty much everywhere, all the time -- is 460 C. How can Venus be twice as far from the sun but so very much hotter? Well, Mercury has almost no atmosphere, while Venus is covered with a thick blanket of CO2 at a pressure of more than 90 atmospheres. It's the greenhouse effect on steroids. (And no, I'm not saying that Earth will turn into Venus. It just shows that the greenhouse effect exists and is not some made-up mumbo jumbo).

If you think of Mercury as a Mini Cooper zipping around on the freeway with the windows hanging wide open, and Venus as a Lincoln Navigator parked in the sun with the windows rolled up you get the picture. Earth is somewhere in between Mercury and Venus: we're parked in the shade, but slowly cranking the windows shut by pumping more CO2 into the atmosphere than the system can absorb.

But when you come right down to it, Bastardi's argument is the same as every other global warming skeptic's: they think that natural processes put out and absorb so much CO2 that the "tiny" amounts we puny and insignificant humans emit couldn't possibly affect the climate. But this drastically underestimates the number of humans alive today, and their impact on climate.

First off, climate is always a delicate balance. Systems do tend to equilibrium, but only within bounds. Natural systems don't have an overriding intelligence guiding them, they can't adapt infinitely. If you heat a pot of water it reaches equilibrium with the air by boiling out of the pot.

In many epochs equilibrium climate states lasting thousands and millions of years were quite inhospitable to modern human life: there have been ice ages during human tenure on Earth, and there have been periods where the climate allowed three-foot long dragonflies, armadillos the size of houses and flying dinosaurs to flourish. Those were all "natural" climate equilibriums, but they would have been bad for technological humans because they make it hard for us to grow food and sustain a population of seven billion people.

Second, we control vast amounts of energy. If we detonated every nuke on the planet, there's no question we could make a big change in the climate, easily triggering an ice age with all the aerosols injected into the stratosphere. But if you look at the amount of energy we're using on a daily basis, it's equally staggering: the equivalent of hundreds of Hiroshima nukes detonated every day. We are using an incredible amount of energy, and generating nearly all that energy from coal, gas and oil, releasing an incredible amount of CO2 into the atmosphere that had been locked up in the earth's crust for billions of years. All released within a tiny span of a century, and most of that in the last 30 years.

Third, we just don't get how many people there are on this planet and what kind of an effect we can have on it. The United States is 3.79 million square miles in area. There are 310 million Americans. That means there's only about eight acres of land per person (given that there are 640 acres per square mile). Eight acres is one or so city blocks.

Even if all you had was an axe, you could cut down every tree on that block in a few weeks or months, and spend another couple of weeks chopping down the trees for your little kids and grandma. Or if you had a torch you could burn all those trees down in a day. We are so numerous and technologically adept that could intentionally deforest the entire continent in less than a year, drastically altering the climate.

And we can and have altered the climate. Just look at the Dust Bowl in the 30s, which Bastardi mentioned. That was caused by a drought in the plains states exacerbated by farmers plowing up the long-rooted grasses that held the soil down. Without us the dust bowl doesn't happen. We've been doing the same thing in the Amazon rain forest for decades, and there's some evidence that humans helped the Sahara get where it is today.

There are seven billion people on Earth. Humans are always bad at understanding big numbers, so let's put that in the same personal perspective. The total land area on this planet is about 56 million square miles, or 124 people per square mile, or just five acres per person. Yes, if you spread all of humanity out evenly across the entire planet, we would all still be within shouting distance of another person.

That's including all the land that's useless (the Sahara, the Antarctic, the sides of all those mountains in the Himalayas and Japan). That's not a whole lot of land for all the farming, and mining, and driving, and golfing that we like to do. Imagine what it'll be like in another 50 or 100 years. Conservatives love to knock Malthus, but there are obvious limits here, and we're fast approaching them.

We ourselves are now that big incomprehensible number.