On the Need for Additional Evidence

There is an interesting new report from the University of Waterloo that claims Chlorofluorocarbons (CFCs) are the chief cause of global warming since the 1970s. It was published in the International Journal of Modern Physics B  last week. As phys.org explains,

CFCs are already known to deplete ozone, but in-depth statistical analysis now shows that CFCs are also the key driver in global climate change, rather than carbon dioxide (CO2) emissions.

"Conventional thinking says that the emission of human-made non-CFC gases such as carbon dioxide has mainly contributed to global warming. But we have observed data going back to the Industrial Revolution that convincingly shows that conventional understanding is wrong," said Qing-Bin Lu, a professor of physics and astronomy, biology and chemistry in Waterloo's Faculty of Science. "In fact, the data shows that CFCs conspiring with cosmic rays caused both the polar ozone hole and global warming."

"Most conventional theories expect that global temperatures will continue to increase as CO2 levels continue to rise, as they have done since 1850. What's striking is that since 2002, global temperatures have actually declined – matching a decline in CFCs in the atmosphere," Professor Lu said. "My calculations of CFC greenhouse effect show that there was global warming by about 0.6 °C from 1950 to 2002, but the earth has actually cooled since 2002. The cooling trend is set to continue for the next 50-70 years as the amount of CFCs in the atmosphere continues to decline."

I might not be the most qualified person to criticize Dr. Lu's work, but I do think we should not jump to conclusions right away. The carbon/ temperature record goes back a long time, tens of thousands of years if we are referring to ice cores.With that much data, it's fair to say that the very strong correlation between carbon and temperature can be assumed to continue to the future. But even with that much data, establishing a causal basis can be very difficult. Since we can't run control experiments, we'll almost always have enough uncertainty in the data to keep climate denier websites busy for decades.

The black line represents a three-year moving average. Data from the NOAA, which is available here.

Considering this challenge, I find it very presumptuous to go that far against consensus based on only 10 years' worth of deviation from the original trend. The argument for CFCs is based entirely on the fact that temperatures have not risen as quickly as CO2 levels in the last decade, even though it remains much hotter than any period before it. Considering measurement challenges and the huge number of almost random processes that influence weather (just ask Lorenz about that), it seems presumptuous, to say the least, to claim that CFCs are the only compounds that matter. There's just too much that we don't understand to make that claim with that little of evidence.

To be fair, I'm not claiming that CFCs don't matter in this debate. I only want to recommend caution about extreme claims. A much older report from the US Environmental Protection Agency did say CFCs were responsible for about 15 percent of global warming. They could also play a strong role in the less-than-expected recent rise in temperatures. So could volcanoes, so could a lot of other things.

So what's really going here? Academics have strong incentives to make almost absurd claims, since it helps them get published, and it generates references. While this can be annoying on a case by case basis, the overall scientific discourse benefits from the trolls as it forces people to expand their cases and move the debate forward.  It will take a lot to overturn consensus at this point, since about 97 percent of scientists in a recent survey agree on the mechanism and the effect. As readers of scientific literature, wish should keep this in mind. Prior beliefs should be adjusted only when there is substantial evidence to change course. So far with CFCs and global warming, we're not there yet.

Empiricism and GMO's

Despite the overwhelming empirical evidence on the safety of GMO's some of my friends still refuse to leave organic foods for other alternatives. You may be surprised to hear this, given the content of my previous post, but I fully support them making that choice. My only problem is with those on the Left (and Greenpeace in particular) forcing their choices onto others and the usage of patent nonsense all along the way. And the methods they've chosen to use for this force-feeding of values are sick too. I've done enough talking about all that already.

That's the huge irony in the whole labeling debate: people that want to avoid industrial agriculture already have organic food. It's (mostly) clearly labeled. You might not like the organic standard (I think some of the exceptions are absurd), but the non-GMO food is basically labelled for everyone interested.

Your choice is there, and it's clear. Go and seize the day. No one from my side has any interest in removing your choice. Nor will that change.

But making the choice of organic and only organic, you're also committing an intellectual fallacy that needs to be addressed. All problems have to be treated with the same intellectual rigor and basic decision process. There are no exceptions. This process is pretty simple too, as you apply it every day, all the time to make the huge number of decision you need to survive.

Take the decision to talk on a cell phone, for example. Thus far, we have not proven that cell phones, if used consistently for 50+ years, will cause cancer. The technology hasn't been around long enough for that "test" to be undertaken yet. But there is a chance that when used consistently for decades straight, they might. There is also some chance that all of the current research about cell phone safety could become moot because of a particular quirk in 15G technology that allows our alien overlords to seize control of our brains. Who knows? The future is uncertain.

Similarly, I don't know with total certainty that my boss will never barge into my office, leap across my desk and bite my face off in the future. Lacking perfect foresight, I face fundamental uncertainty about this. Who knows what will happen when that chemical stash in the middle of the Aral Sea explodes?

In both situations, I use empirical observation about personal occurrences and similar accounts to make a forecast of the future. My cell phone has not caused a problem to me or anyone close to me thus far (although the aliens may want me to think that), so I go on using it. Similarly for my boss. Since there is a large number of observations about this particular incidence, I can conclude that I have a high probability of being safe.

Now, those examples may be trite, but look at what so many people are doing with GMO's. They are throwing out fundamental decision-making tools to make an argument they find emotionally satisfying. There is twenty years of data, hundreds of millions of meals consumed and the expert opinion of the world's leading scientific bodies all pointing to the conclusion that GMO's pose very little risk. My basic assumption, based on empirical analysis, following the same technique that governs all of my other decisions, has to be that they probability of risk from GMO's is very low. With each passing year, that probability also has to decrease.

Now, if something bad happens, all of these assumptions will change. As Keynes said, "When the facts change, I change my mind. What do you do, sir?" If even a single person died of eating a GMO, my assumed personal risk has to increase. Similarly, if I was in a situation where there was not a whole lot of prior information to follow (like my future prospects in a cooking school) or the data was intentionally constrained (housing prices have increase for the last 5 years!!!), my assessment of risk has to be much higher. But with GMO's, we're not in that situation. We know, for the entire history of this technology, that the products delivered to market have been essentially OK. Those situations that stand out (like a type of tomato that caused allergic reactions in mice in testing), have all kept specific types of GM food off of the market because on the security measures we have in place. This should make you even more confident about their safety.

This is what I think is so great about Lynas' speech. The scientific method (and what I described above is essentially the Bayesian approach) should not be selectively applied based on our ideological preferences. At the same time, we also don't get to be intellectually lazy. A conclusion that something has a high or low probability of occurrence has to be backed by strong empirical evidence and that evidence has to be constantly refreshed. But this basic rule says GMO's are OK. Just like it says that climate change is a big problem, as are the resource constraints formed by a growing population experiencing broad economic development.

In the meantime, there are serious problems that GMOs can solve, and the people suffering from poverty and malnutrition right now don't need us to wait 10-15 years to solve them. They deserve better than that. It's ridiculous for governments to be still interfering with food products that have been in testing for 5 years within an industry that has proven, at least thus far, to be safe. It's time to end this debate. Take the technology we have and go solve our pressing problems. We have no excuse for waiting.