This diary is in response to the diary entitled "Want to see a real crisis? Global Warming heating up" written earlier today.
link: http://www.dailykos.com/story/2005/1/24/161343/528
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I'm writing in response to the earlier diary because the amount of disinformation floating around the public domain, from both sides, is staggering. I felt that I needed to clear up many of the inaccuracies present in the earlier diary, and present what is considered the current state of knowledge in the discipline about these subjects. This isn't an attack on VirginiaDem for his/her posting, its simply an attempt to present a scientists view of the state of knowledge on these subjects without including spin from either the left or the right (and on this subject, there is considerable spin from the left as well, unfortunately). I firmly believe that the left tends to be the reality based community, when the facts are known, and it is in this light I present this diary. (more below the fold).
Some background: I'm a research scientist working at the College of Atmospheric and Oceanic Science at OSU (one of the big oceanographic institutions in the US, right behind Scripps, WHOI, and UW), so I have some knowledge about these subjects.
Second, although I've read dKos for over a year now, this is my first diary.
Third, while I can reference a number of papers in peer reviewed journals, most of you won't have access to them. Thus, I will try to keep such references to a minimum, and stick with links I can find on the internet. However, to really understand the scientific findings on some of these issues, those references are important, and if anyone is interested I can and will provide that information.
Unfortunately, the report isn't available online: you can order it here for about 10 dollars, http://www.ippr.org.uk/publications/index.php?book=462 , but as I have not read the report, I cannot discuss its contents. However, I can discuss the subjects touched on in the CNN summary.
First: a history of earth's climatology - temperature records
I found this website in writing this discussion, it's quite a find! It has all the information I wanted to convey in this section compiled for me already! Read this, and return
http://muller.lbl.gov/pages/IceAgeBook/history_of_climate.html
Lets discuss. The first graph, alarming! This is what most people who will scream global warming at you will point out. The graph shows the past 120 years of temperature records, and there is clearly a 0.6 degree increase starting at about 1900. This, in fact, is what the CNN article suggests is part of the significant increase of global temperatures from 1750 onwards that are rapidly approaching the `critical point' of 2 degrees C.
Second graph: now we are looking backwards 2400 years - from the dawn of Roman civilization to modern times. Note the scale of fluctuation temperature is much larger than the entire range shown in the first graph. Now we are seeing fluctuations ranging over 1.5 degree C. Note that the warm periods (during the roman empire for example) are considerably warmer on average than the past warming event after the little ice age.
The third graph now looks 10,000 years into earth's past, such that we are beginning to see the dip into the most recent of the last true ice age. The end of that ice age coincides with the beginning of recorded human civilization. Climate certainly has an impact on human culture, but note the temperature scale- we are now looking at total temperature changes of 7 degrees. The modern variation (or even the little ice age) is nothing but a blip on this time scale
Next graph, 100,000 years of earth's past. Now you are looking at the entirety of an ice age, compared to the tiny stable section of warm temperature 7000 years long that we inhabit now. Look at those huge fluctuations in temperature during the ice age.
Next graph, 420,000 years of earth's past. Now we are looking at four ice age events, separated by little islands of warm temperature such as the one we inhabit. Those interglacial patterns are short, and we are nearing the predicted end of the current one. They have a time scale of about 100,000 years. - these are the Milankovitch cycles and are theorized to be linked to the insolation of the Northern hemisphere via axial tilt. While the point of this diary is not to get into the details of paleo-climate theories, there is considerable debate to this day on the mechanisms responsible for the strong periodic structure of the observed cycles of ice ages.
Note that in the last figure, now looking three million years into the past, at the scales of temperature fluctuations. In the past million years, the fluctuations are typically 100,000 years in period, but previous to that, the ice ages tend to be smaller in amplitude, and shorter in period (41,000 years). Approximately three million years ago (Dinosaurs!) the temperature record reveals an earth that was, on average, 5 degrees warmer than current day with no ice age fluctuations of any significant magnitude.
While the point of this diary is not to get into the details of paleo-climate theories, there is considerable debate to this day on the mechanisms responsible for the strong periodic structure of the observed cycles of ice ages. One of the most likely theories suggests that coupling between astronomical forcing (Milankovitch cycles) and the distribution of land mass modulate the temperature record as presented here.
If I could show you a picture (I cant find one on the web) looking back a 100 million years, into the time of the dinosaurs, even more complicated temperature records emerge. Now we are talking about shifting entire continents around modulating the temperature structure.
What then is the point of this synopsis of a small record of earth's climatological history?
Firstly, any report or statement that talks about Earth catastrophe is just absurd. Earth, the planet, and Earth, the ecosystem, has endured temperature changes of greater than 20 degrees C, not to mention asteroid strikes, super volcano's and all sorts of really horrendous catastrophes. Two degrees C is nothing, from Earth's perspective.
Second: what is undeniably true is that mankind (industrial revolution) is responsible for the rapid increase in CO2 - there is nearly unanimous scientific consensus on that point. Here is the most famous record:
http://www.uwsp.edu/geo/faculty/lemke/geog101/referenced_diagrams/co2_mauna_loa.html
What there is considerably less agreement in the scientific community about is the impact of that CO2, although this debate never really makes it to the public, except in biased studies released by either the pro-fossil fuels group on one side and the Greenpeace activists on the other.
Global Climate Models (GCMs) are the best tool we have as scientists to predict the outcome of future climate based on various changes. The problem is that, even today, none of these models really give good agreement with each other, some predicted 3 degrees warming over the next 50 years, others predict 1 degree cooling, and everything in between. Why are these models so atrocious? Well, they aren't. Its simply a matter of appreciating the difficulty. Imagine a computer model that is used to model your car's exhaust system. Currently it is JUST possible to model the Navier-Stokes equations to the necessary detail to include all the physics of that system. Thus, one can model that system nearly exactly, turbulent flow included.
Now, jump up a scale, model the flow of air around the entire car. Can't be done exactly, the turbulent flow must be parameterized - we cant solve it exactly, we put in an approximate equation making up for the scales we cannot see in the model. To include those missing scales exactly, we would need to up the number of grid points by a factor of 10000 and no computer could run it.
Jump up another scale - model the coast of Oregon. Now your grid scale is 1 km by 1 km by 10 meters. Everything that occurs inside that 1km is parameterized, not solved for exactly. What do you need to include? Wind forcing, solar heating, evaporation, condensation, river inflow, prior state, boundary conditions.
Ok, now lets do the earth, for 1000 years. Now we are talking about a model in which each grid point is separated by 10 km on the horizontal and 200 meters vertically. You need to include interactions with the atmosphere, so you need an atmospheric model as well. You need to include solar inputs, reflectivity of clouds (and thus cloud formation), reflectivity of ice (and thus ice formation), wind current interactions etc. etc. as well as the effect of atmospheric CO2, and this is ALL parameterized - none of it can use the primitive equations because the model is too big.
So, the state of the art GCMs are making progress. They are getting there. Some of them can predict ice ages (roughly) if given the correct inputs. But are they able to predict 2 degree changes of temperature due to increasing CO2 by 125%? The answer so far is, no, not with any degree of confidence.
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Ok, so what is the take home message? What can we do, and what should our message be? How do we frame this message?
Well firstly, its very much in debate whether or not the last century of warming is at all manmade. The trend of warming over the past 100 years certainly suggests that it may be, at least partially, due to manmade sources, but its hardly conclusive. Given the shear magnitude of known climate variability, the current change is nothing but a hiccup, smaller than that seen 2000 years ago.
What we need: better GCMs. Scientists are working on this problem and will continue to do so in the foreseeable future. This is certainly a hot topic and receives more than its share of funding - GCMs will continue to improve but there is not much we can do to speed this process up.
We also need an informed public that can talk about this debate in terms of knowns, instead of scare tactics by the doomsday crowd and denials of climate change occurring at all from the religious right.
In my opinion, cutting fossil fuel is a complete unknown, and the world's best minds on the subject feel the same. I've been fortunate enough to attend seminars by Walter Munk and Wally Broecker on this subject (some of the foremost oceanographers) - Wally's take on this is simple - he is not convinced that raising the CO2 is linked to global warming, but based upon available evidence; he informally puts the odds at something like 50-50 of that link being true. He suggests that, given those odds, perhaps it's not in our long term interests to continue running this experiment on our planet, given the possible consequences (transition into the next ice age). (A paper of his can be found online here: http://faculty.washington.edu/wcalvin/teaching/Broecker99.html that I recommend reading.).
Finally, this is how I would frame the debate.
First, the public must understand that, manmade or not, climate change is real, and even small changes have large effects on our society. The little Ice age - a 0.6 degree drop - made colonization of North America by Europeans impossible - even at the end of the little ice age, the winters were so long and severe that they killed entire colonies. A 6 degree change is catastrophic - it was the difference between 30,000 years of human history being unrecorded bands following game and civilization.
Second, it must be framed in these terms: It is catastrophic to human societies and cultures- it has huge economic and social consequences. Not only is it incorrect to say that climate change endangers the planet, it doesn't, or life on earth, it doesn't, but most people you are trying to convince with that argument are going to blow you off as a hippie tree-hugger save the spotted owl (insert cliché here) do-gooder. What is certainly true, and IMO, more likely to impact people, is that it will most certainly effect them - the long term costs of climate change are significantly more severe than the short term costs of preparing to deal with it. Flooded cities, weather pattern shifts, farmland destruction, etc. all have big price tags and big death counts associated with them. If two severe El Nino events in a row (not, btw, related to climate change) can decimate countries agriculture, fishing, and ranching industries (Australia, Chile) people can be made to see that climate change can do the same. Potentially, it is possible that triggering the onset of the next ice age could destroy human civilization, but IMO you really don't need to go there. Its abstract and unreal to people - its much easier and much more effective to discuss how, based on cost benefit analysis, ignoring the problem is not a good idea.
Third, while I agree with Wally Broecker, in that dumping CO2 into the atmosphere is probably a stupid thing to do when we don't really know the consequences and wont for another decade or two at least, I don't see much of a way out of it, save for a rapid switch to nuclear power for most of our energy needs (something I am most definitely in favor of). While I do think we need to do what we can to curb CO2, I think, for the same reasons, that we need to start spending money now to prepare to deal with the coming changes which may not even be man made, and thus inevitable. Population centers need to prepare for rising sea levels, and agriculture planning needs to be done for possible shifts in rainfall and growing seasons. Spending money now on preparing to deal with these changes will prevent huge economic and humanitarian catastrophes in the not-so distant future.
If you've made it this far, thanks for reading, and I look forward to the discussion
-Yertle