But IS it a controversial issue? Actually, NO, it isn't, not even remotely. Then, why is it so often debated on the news or in political discussions? Well, I think there are probably a few reasons for this. The first is that perhaps any given media outlet has a particular agenda to enforce - so, for example, they simply ignore the facts that the Earth IS in fact warming.
More likely though is that there is the illusion of debate and disagreement between scientists about this issue. The problem is that while, yes, scientists will often disagree on particular issues, this is no longer one of them. Yes, in the past, it was under debate - though, as I explain below, "debate" isn't really the right word. There is now overwhelming consensus in the scientific community (in particular, among atmospheric scientists) that global warming does exist and that it is in fact caused by us!
But what does this mean, "overwhelming consensus"? Does it mean a bunch of scientists got together one day and voted on whether or not man-made global warming is real? The answer is no. Many people don't understand the meaning of scientific consensus. I'm not blaming the layperson here - the blame could be put on our education system for not properly teaching students the way that science works (see here for a scary but excellent story related to this) or it could be put on scientists for not doing a better job at communicating how we think and work (though, I tend to think we are doing the best we can given the little money that we get for education and public outreach!).
Scientific consensus basically means that there has been a LOT of scientific research done and all of the results point to the same answer. It is not the same as debating whether or not we should raise or lower taxes by a certain percentage. A better analogy would be us knowing that the Sun will rise every day. Why? Because it has over and over again ever since the birth of our planet, and we understand exactly why (the answer being the rotation of the Earth). The data is there, the event is predictable, and yes, every day the prediction of the Sun rising is accurate.
The same is true for global warming. Yes, you can always find scientists who disagree with the results and have their own ideas for what is happening. However, they are very rare - there are still scientists who contest the idea of our universe being created via the Big Bang! All of the data, all of the research, all of the papers published point to the same result - man-made climate change is real.
And no, this post is not some sort of ploy to get more money from the government - hell, I don't even work on climate science! This post is here to educate people that if we don't do something about global warming, our coastal cities could very well look like this in the not-too-distant future:
Not to mention many many other environmental disasters (some of which we may already be feeling!).
Well, this post has gone on long enough. There is a lot more I could say on this issue, but for now, I refer you to Scientific American for more information. And for the love of God, do NOT get your information from biased media sources like Fox News or MSNBC.
This post presents these facts as if they were a pure and true evidence, but I don't think they are, and for several reasons.
ReplyDeleteFirst the fact that there is a "scientific consensus" does not mean that the conclusions are correct. There has been several scientific consensus which have been incorrect (think of the aether theory or ptolemaic models). To me, having a big consensus is actually bad since it prevents outsiders to be funded and heard by the community. You cite the big bang theory as an example of a consensus. The big bang theory is very successful at predicting some very important facts including nucleosynthesis and the CMB. But it also implies that we are surrounded by a lot of dark matter and dark energy, and we have no idea of the origin of these things. In the end, these unknowns represent 95% of the content of our universe, and still, we've never seen these in labs... Still, because of this consensus, it is very hard to question these conclusions, or worse, to propose alternative models and be heard. Science is the art of doubt, and consensus is the exact opposite of that. As scientists, we should have doubts about everything, it is the definition of our job...
Now, back to climate change. Nothing is strictly white or black, and so is global warming. Look at recent data ( http://www.economist.com/news/science-and-technology/21574461-climate-may-be-heating-up-less-response-greenhouse-gas-emissions ) showing that global warming seems to be stalling since roughly 2000 and is slowly deviating from computer models... CO2 levels are still increasing, but for some reason, the temperature have been steady for 10 years. And that's only global warming, it does not question the implication of human activity in the equation!
There are several other problems of this kind. In Europe for instance, it's been said that the hot Mediterranean climate will move north up to Belgium due to global warming. Now, it is said that the local climate should actually cool down, as it's been observed this winter, due to the melting of the northern polar cap... But presumably next year it will go up again, or not.
The conclusion of all that is that the Earth climate is a complex non linear system subject to local and global bifurcations, hysteresis, etc. To me, it is not clear at all that we are able to predict what the climate will be like in 50 years, especially with models which are oversimplified and not quite predictive (this is not a criticism, we just don't have enough computer resources to simulate very accurate models). You moreover have to take into account the evolution of the economic activity and natural resources (including oil production, etc.), something which is not included in climate models of IPCC (and for a good reason: we don't know how to model that, we don't even know what the economic activity will be from one year to the next).
As scientists, we know these limitations, we know the underlying hypothesis, we know "how it works" behind the scene. But when suddenly we have to communicate with a broad audience, when one has to make a political decision based on these results, these words of caution disappear. And all of the sudden, results appear much stronger than they actually are. I believe that's partly what's happening with this global warming theory.
I do believe that human activity is probably partly responsible for some of the changes we observe in the climate, but that's a belief, an intuition, not a scientifically established fact.
I agree with you G. Lesur, quite a bit actually. So, let me clarify a few things about the post and how I write in general.
ReplyDeleteFirst, the idea of scientific doubt is of course not foreign to me, since I am a scientist. However, for the purpose of keeping my blog posts short, I don't go into the idea of doubt for every single idea that I post about. My point was that there is overwhelming evidence that supports the idea of man-made climate change. Of course, there should ALWAYS be doubt (I think I will do a post on scientific uncertainty in the near future), even for the most well-established theories. That may be the only way that science progresses at times - we have doubts about a theory and then we design experiments to further test them, and perhaps we find out that the theory needs to be revamped, changed, or whatever. But, what I was trying to get at was that the media claims that there is this huge debate on whether or not the evidence even supports man-made global warming, and this is just not true, at least not to the level that the media makes it out to be. Most non-scientists that I talk to don't seem to understand that almost every single atmospheric scientist agrees that the evidence strongly supports man-made global warming.
Now, you bring up another good point, which "is our idea of how this global warming is occurring even correct?". You are right that we should be very cautious here because to verify a scientific idea, we have to develop a model that makes accurate predictions. And as you say, climate modeling just isn't sophisticated enough yet (compared to the vast complexity of the entire Earth) to make such accurate predictions.
However, the evidence for man-made climate change is still strongly present. One analogy would be the experiments that showed that the speed of light was constant no matter how fast one is moving. Eventually, the conflict of this result with Newtonian physics would be resolved using Einstein's theory of special relativity. But there was significant evidence before this complete resolution that the speed of light was constant in all frames.
The distinction I am trying to draw is between evidence of a phenomenon and a theory that fully explains it. Yes, we may not fully understand global warming (and this should lead to caution in designing ways to counteract it). However, the evidence for it and for it being man-made is convincingly strong.
Is there the possibility that we will eventually discover otherwise? Of course, and as we both know as scientists, it is our job to pursue questions about other possibilities.
And another thing: I thank you for commenting and debating me in this manner. I know that I will not always be correct or say things in the best way possible. So, I always welcome comments and thoughts like this.
ReplyDeleteYou aren't the first person to mention the wording in my posts, and I do realize that often times, I leave out particular details. However, the idea is to get a concise post that strongly delivers a clear point. Perhaps I should add in more about scientific doubt, but it's a balancing act between brevity and comprehensiveness.