free debate

December 28, 2009

Skepticism and Climate Change

Recently there has been a lot of discussing regarding climate change within the skeptical community. Famous skeptic James Randi and science educator Johnny Ball, have both expressed their doubts as to the effect humans are having on climate change. The was a media storm as some embarrassing private e-mails between climate scientists were made public. This has raised several questions including what is the evidence for climate change and what is the role of skepticism in this issue.

Any issue that is highly politicized is hard to find good information on. We have discussed the issue of climate change a few times before on this blog (here and here) but I want to quickly review some of the science. There are several claims made with regard to climate change. The first is that the globe is, on average, warming. I think most people accept this fact. The debate is over the cause. The Earth is in a time period where we would expect to see temperatures rising naturally to a degree. The debate is over how much of the current warming trend is natural, and how much is caused by the human emissions of greenhouse gasses like CO2.

When we are dealing with an issue as complicated as climate change, we want to look at the scientific consensus. We don't want to look at the opinion of every scientist on the planet, but of those scientists who are doing work in relevant fields. The Intergovernmental Panel on Climate Change (IPCC) is a group composed of thousands of scientists from countries around the world. They have said in their most recent publication, "Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG [greenhouse gas] concentrations." There is a growing amount of evidence that backs up this conclusion.

There is another debate on how we should react to climate change, but that is for a future post. My question here is what is the role of skepticism in regard to this evidence.

In science, opinions that go against the consensus play an important role. Grants will often go to people doing research that goes against the grain. I am glad that there are scientists that are working on finding problems with climate models and trying to poke holes in the other lines of evidence for climate change. This said, I think we have to remember this is a minority view.  Skepticism is about forming views based on the evidence. So far, the evidence points strongly towards a human contribution for climate change. I think that regardless of our personal viewpoints we need to respect that. I have no problem with people like James Randi expressing doubts about the human influences on the climate. I have said before skepticism is not a set of views, but a process for forming ones own views about the world. I do think though that to be responsible, leaders like Randi need to be clear that they are disagreeing with the scientific consensus. There are sill places for their doubt. We are still are developing climate models, and their are error bars for the evidence (see the image above). I don't find these arguments convincing, but others do and that's where the dialogue should be.

I personally find the evidence for the human influences on climate change overwhelming. I always welcome people to disagree with me, but please do so with evidence and logic. Recognize that the scientific community has overwhelmingly showed their support for this view. I think it is unfortunate that there are people who disagree with me based solely on its implications or for other political reasons. I have have talked with scientists on both sides of this issue, and I think that the most reasonable thing to do is respect the conclusion of the majority of working climate scientists.

December 18, 2009

A Glimpse of Lakes on Titan

Imagine a world so cold that temperatures like -270 Fahrenheit are not uncommon.Water acts more like rock, and a thick orange atmosphere looms overhead. Instead of water carving up the landscape, you have methane. This is Saturn's moon Titan.

This image is of sunlight bouncing of the lake Kraken Mare taken by the Cassini spacecraft. This lake of liquid methane is larger than the Caspian Sea here on Earth. Titan is a fascinating world because of how it compares to the Earth. “These results remind us how unique Titan is in the solar system,” said Ralf Jaumann, a visual and infrared mapping spectrometer team member on Cassini. “But they also show us that liquid has a universal power to shape geological surfaces in the same way, no matter what the liquid is.”

There has been building evidence for lakes on Titan even before Cassini arrived at Titan. This picture is a elegant piece of evidence confirming those weird lakes. “This one image communicates so much about Titan -- thick atmosphere, surface lakes and an otherworldliness,” said Bob Pappalardo, Cassini project scientist, based at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “It’s an unsettling combination of strangeness yet similarity to Earth. This picture is one of Cassini’s iconic images.”

Titan is one of the most exciting places in the solar system to explore. I think this just gives a taste of what awaits us.

For more information: Cassini Homepage
Image Credit: NASA/JPL/University of Arizona/DLR

December 16, 2009

Mobile Home for an Octopus

Tool usage was once considered to be one of the key features separating us from other animals. However, recently we have discovered that most primates, some birds, and a few other mammals use tools as well. And now, for the first time, we have found an invertebrate using tools. The best way to describe this is simply to watch:

These octopi, Amphioctopus marginatus, are using the coconut shells are a protective home. Now, you might think that this is similar to what hermit crabs do. After all, they are also an invertebrate which uses discarded shells to protect themselves. However, a hermit crab's shell is more like a hat for us: just put it on and forget about it. The coconut shells of these octopi are much different. As you could see in the video above, the creatures hold the shells under their bodies and "run" along the sea floor. They also go through an elaborate process to put two coconut halves together, completely encasing themselves. Far more effort than simply putting on a shell and forgetting about it.

The adaptations that life on this planet have come up with are pretty incredible. We've just scratched the surface in learning about our fellow creatures on this planet. More research is certain to reveal even more amazing behaviors.

For more information, visit National Geographic.

December 15, 2009

Dinosaur Debate: What Killed the Dinosaurs?

Like the warm versus cold blooded debate, this argument has been around since the first dinosaurs were identified. It's pretty easy to tell when the dinosaurs went extinct: dinosaurs are found in rocks older that 65.5 million years, and are not found in rocks younger than 65.5 million years (with the exception, of course, of birds. But, for the purpose of this post, assume that dinosaurs are non-avian dinosaurs). But what killed them is a much more challenging question. There are several popular hypotheses, with varying scientific support, as to the cause of this mass extinction.

December 14, 2009

What is Science? (Using Unknowns to Prove a Point)

Carl Sagan famously said, “Absence of evidence is not evidence of absence." On the flip side, proponents of a nonscientific idea will sometimes invoke a lack of evidence as proof of something. Evidence is a tricky thing, and a lack of evidence can easily fool many people.

A absence of evidence is often cited in the debate regarding the existence of other life in the universe. We have never received signals from ET and, while there have been tantalizing hints of life on Mars, nothing has even come close to being confirmed. So with no evidence, are we forced to just admit that we are the only lifeforms in the universe? No, we have just begun to scratch the surface of looking for life beyond the Earth. Just because we don't have evidence yet doesn't mean we won't find it.

This idea can be taken too far. Just as we have a absence of evidence for life on other worlds, we also have a absence of evidence for unicorns. It is logically impossible to prove a negative (like unicorns don't exist) so are we forced to accept them as equal possibilites? In science, we can assess the plausibility of a claim. It is highly plausible that there is life outside the Earth that we have yet to find considering how little of the universe we have explored. We have however, explored a vast majority of the land mass of the Earth and have yet to find unicorns. While there is nothing intrinsically impossible about a horse evolving a horn, we just haven't found it in our explorations. So, while a absence of evidence may not be evidence of absence, we can still use current knowledge to judge the likelihood of different claims.

The other way people try to use the gaps in our knowledge is to prove claims. This is known as the argument from ignorance. In my experience, this is one of the most common logical fallacies. The basic argument goes because we don't understand X, Y is true. This is often invoked with quantum mechanics. People will make arguments to the effect that because we don't understand the quantum world, psychics really have powers. The same argument could have been used only a few centuries ago to say because we don't understand flight, humans can fly by flapping their arms. You can't use our lack of understanding to prove anything.

It is not hard to find people on the internet and in real life committing both forms of this flawed logic. Whenever you encounter a claim, make sure you ask yourself if they are using unknowns to make their arguments. Are they asserting someone is true because we don't understand something? When it comes down to it, a lack of evidence is evidence for nothing.

December 7, 2009

Ancient Practices in Modern Medicine

Whenever I debate people on unscientific medical practices like acupuncture or homeopathy, it seems that people will inevitably cite ancient wisdom as proof that it works. This is actually a logical fallacy, the appeal to age or tradition. Pointing out logical fallacies in informal debates, however, rarely helps (which is a topic for another post). Normally, people rationalize it by saying things like "Well, only the good cures stuck around." Unfortunately, in debates like this, I get branded as the one who thinks that the ancients couldn't get anything right. So, I want to set the record straight as to what the role of ancient wisdom is in science-based medicine.

In the ancient world, medicine was rudimentary at best. In many cases, you were better off receiving no medical intervention then if you went to a "doctor". Ideas for the cause of illness ranged from witches to unbalanced humors. "Cures" included everything from leaches to exorcism, and a little more recently, radioactive water. It is practices like this that I will speak out against, because they are not supported by evidence. However, we can't just say that all ancient cures are bunk.

Willow bark was a well-know pain reliever to ancient peoples. Willow bark was also quick to enter the scientific literature. As early as 1763, research was being done on the benefits of willow bark for fevers and pain relief. After observing its therapeutic effects, scientists found the active ingredient (salicylic acid) in the bark and isolated it. Now we know this as aspirin. Science did not ignore the effect of the natural cure (willow bark), but instead figured out how to refine its to make it even more safe and effective.

Science does not ignore ancient cures; in fact, it does the opposite. Particularly as it was getting its footing, science-based medicine has looked at traditional cures to see which ones work. Some like homeopathy and acupuncture have fallen by the wayside, while aspirin and the Indian Neti pot have be completely validated. We should look for plausibility and evidence for every medical intervention. Science doesn't assume that just because people still do it, it works. Neither should we.

Image Credit: Bruce Marlin

December 3, 2009

Massive Supernova reveals a Supermassive Star

Type II supernova are the result of a massive star running out of fuel at the end of its life. Normally what is leftover is a neutron star or black hole, the super compact remnant of the dead star. I had always assumed that as the mass of the star went up, you just got a more massive object leftover. Astronomers have found a star so massive that nothing remains after it dies.

Located in a nearby galaxy, this supernova lasted 50-100 times longer than its typical counterpart. "It was much brighter, and it was bright for a very long time," said researcher Paolo Mazzali of the Max-Planck Institute for Astrophysics in Germany. "We could observe this thing almost two years after it was discovered, where you normally don't see anything anymore." The star is estimated to have been 200 solar masses, the biggest star ever found. Astronomers were beginning to doubt that stars this massive could even exist.

This a wonderful example of observation confirming prediction. It was hypothesized that if these massive supernova existed, they would have a specific signature. This supernova matched that signature. Because this star was so massive it went supernova early. When smaller stars (but at still least 2 solar masses) would be fusing iron in their cores, this star created matter anti-matter pairs that set off a nuclear chain reaction. It is always exciting when astronomers discover a new type of object, especially when those objects involve a really big explosion.