For Jeff King: Global Warming

Jeff asked: Is global warming valid; is it really true in your mind?

Yes. But let me clarify.

The term, "global warming" is probably accurate for the long term. In the shorter term, the term "global climate change" is probably more appropriate because the process isn't simple or readily predictable.

But do I think humans are in the process of making a profound (and potentially somewhat irreversible) change to the world's climate (and more)? Yes. And I don't know a reputable scientist who doubts it. In the scientific community, what has fuzz on it is not what carbon does to the climate, but how fast it does it, how much is irreversible, and exactly what the impacts are going to be if we (a) stop now and (b) continue to pump carbon dioxide into the atmosphere as if there were no repercussions. The question really isn't, will our children and our children's children pay a price for our excesses? They will. The question is, "How much and which children?"

Right now, for instance, I don't think anyone contemplates a runaway greenhouse like Venus because, hey, that would really kill us all. Even our direst predictions don't take us there (though I might add that all our greenhouse models can't get us to how hot Venus is, so clearly they aren't complete and can underpredict the effects).

But there are a few facts that people who walk into the discussion should acknowledge. First, the greenhouse effect is a demonstrable phenomena. Large amounts of carbon in a simple system can be shown to increase the temperature by absorbing more of the energy from the sun. (See explanation here.) Atmospheric carbon dioxide (and other gases like methane) change the absorption of energy by the sun. That's not in question.

However, unlike a science experiment, the world's atmospheric system is very complex. So there isn't a direct simple correlation to the tons of carbon we pump into the atmosphere to direct temperature change. Why?

There are a number of factors we know about. For one thing, warmer oceans and plant life absorb carbon. However, we don't know whether that can happen indefinitely or if we'll reach a saturation level and stop. And more carbon in the ocean means a greater acidity, which affects a huge and delicate ecosystem. We don't know the repercussions for the water world entirely, but we know it can affect coral reefs and other coastal waters. Even if we didn't have a responsibility to preserve our oceans, we should bear in mind how many millions, no billions, of people depend on the oceans for sustenance.

Warmer temperatures might affect the strength and prevalence of storms, or the extremes of temperatures in the seasons (as might be expected when putting more energy into a chaotic system - you get some unpredictable results). It melts glaciers which uses up some of that energy, but the reduction in ice surface coverage and increases in airborn water vapor (water vapor is another greenhouse gas) increases the energy absorbed even more (as ice reflects more energy away than land or water).

But that sounds like speculation. And, to an extent, it is. We can't tell for certain, what changes will happen, how fast, or what the long term effects will be.

So, why worry? Well, because not knowing how bad it's going to be doesn't mean that changes aren't coming. We know they are because some are here. Glacier retreat is demonstrable arctic ice is at some of it's lowest measured levels. Average global temperature has been increasing. Droughts the past few years have been some of the worst in recorded history - as have been a number of floods and storms. Most of the predictions, even the most dire, about ice loss fifteen years ago, for instance, have turned out to underpredict the actual loss seen, particularly in South America and Greenland.

Glacier melt has been noted as potentially leading to higher sea levels, but the effects are more chilling than that. The same melt that can raise sea levels, can also cause devastating flooding (as glaciers are frequently the sources for rivers) in the short term, but worse, also potentially dry up rivers that literally billions of people depend on for water. That's not hype. It's happening in the Andes right now.

In fact, given the data that's available, I don't think one can reasonably doubt the fact that we have affected the climate. But I'm not sure anyone knows for sure how far-reaching those changes are going to be and when we're going to step in to stop our part in it.

I'm not frightened by the alarmists on this, with their "worst case scenarios." What frightens me is that most of the worst ones I've heard have fallen short of the reality we've seen. Many of the changes we're seeing today, no one expected for another fifteen years.

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For Patricia: The End of the World

Patricia asked: It’s hard for me to decipher “real physics” from the fiction (in Sawyer’s novel) to the often hysteria one finds in media stories (I mean, the Collider does actually exist and they do conduct experiments which could go awry?). Add to that, all the hype over the approaching pole shift or Planet X or Mayan Calendar catastrophe in 2012 and I wonder how much of what we hear of potential or forthcoming astronomical calamities are actually predicted (or predictable) by physicists?

I hear you, Patricia. It’s hard for a lot of people to tell the difference, and these challenges are amplified by the tendency of mass media to (a) focus on the most dramatic elements (even if they are a small part of the whole), (b) they often put their own interpretation on what they hear, even if it’s completely erroneous and (c) they have been knownto put their ownslant on things. It wouldn’t matter so much if scientists had their own direct outlets to the general public, but most scientists tend to write papers for other scientists, so they use language the general public doesn’t understand and concepts that are not common knowledge.

I try not to do that, but I depend on you, my readers, to let me know when I fail.

The side effect of that, though, is that people get what’s going on in the scientific world through mass media and, never forget, media isn’t nearly as concerned with truth as they are with sensation. If a twist in the truth makes a story inflammatory or exciting, most news agencies will pursue it. It’s their business.

This also includes many of our documentaries and shows on Discovery or the Science channel. Scientists might be involved, but the conclusions and dramatic overvoicing are there to make it more exciting, more appealing, more memorable. That means that scientists (such as archaelogists) who, in the real world, would never say something as an absolute (unless they were complete hacks) say things like: “From this picture painted on Pharoah’s tomb, we know the Pharoah was a devoted family man.” No, we know nothing of the kind. It’s certainly possible, but the closest thing we could say we know is that someone (perhaps not even the Pharoah) wanted him to be remembered that way. I could go on and on about the distortion of science, but you really asked about science and doomsday scenarios.

So, here’s what I know. Mayan end of the world, Christian apocalypse, ancient-religion/culture of your choice doomsday - I don’t know any respectable scientist who thinks the end is coming at a specific date. There are scholars and scientists who will say such and such ancient people believed or predicted such and such would be the end of the world, but no one I know of takes it as more than a historical curiousity.

Are there potential doomsday scenarios scientists are worried about? You bet, but none of them have a definitive date. And some are “end of the world” and some are “the world will get difficult for many people on earth.” The Large Hadron Collider is not one that I think reputable scientists worry about.

Of the “world will get difficult” variety, we include most of the self-induced pollution/damage variety: overfishing and oceanic pollution affecting fish populations such that many starve. Ozone depletion leads to increased exposure to UV rays and increases in cancer. Radiation leakage and nuclear disasters (like Chernobyl) have the potential to impact different populations. Ditto for other forms of serious pollution. Loss of wetlands and other buffer zones make human populations more at risk along coastal areas. And, of course, the big one: global climate change as a result of our anthropomorphic changes to the atmosphere that melt glaciers (threatening the water supply for billions of people), induce/increase drought and or storm system, change the coastlines at worst case. I believe most understand that this will not destroy the human race, but can seriously inconvenience it and put many parts of the populace at risk. Also in this category, we include natural disasters like tsunamis, earthquakes, volcanic devastation. These aren’t really sizeable risks for the whole populace, but it can certainly do tremendous damage to affected areas (like those hit with the tsunami in the Indian Ocean a few years back).

When we get to “end of the world as we know it” scenarios, the list is considerably shorter: global thermonuclear war (which I hope is much more unlikely at this juncture than it was 30-50 years ago) and impact from a large asteroid or comet. The latter is something we don’t currently have a way to prevent, has happened in the (far distant) past with huge impacts on the life at the time, and we have clear visual proof that such impacts are devastating. Just look at what’s been done to the moon. Jupiter was hit with a comet in 1994 as we watched. So, yes, it can happen, but there’s no reason to expect it any time soon.

And, if it does happen, there won’t be many (if any) of us left to worry about it.

1. # shakespeareon 29 Mar 2009 at 9:43 pm edit this

   Yup, so we might as well stop polluting and otherwise take care of the earth as much as we can, and not worry about what we cannot possibly prevent.

   Great answer. Intelligent as always.

2. # Patriciaon 05 Apr 2009 at 11:38 am edit this

   I guess I feel better. Thanks!

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