One of the key international bodies working on global warming is the Intergovernmental Panel on Climate Change (IPCC). Every five years, they produce a series of reports incorporating the latest scientific information on climate change, its mechanisms, likely impacts, and options for adaptation and mitigation. The next report is due out this year - and according to a draft leaked to the Guardian, it sets no upper limit on the potential impact of climate change.
This is important. As Tim Flannery notes in The Weather Makers, the IPCC is by its nature an extremely conservative body. It has to be, when every word has to be fought over with outright deniers such as Saudi Arabia and the USA. So, when it says something, you expect the reality to be much, much worse. In their last assessment, summarised in the 2001 Synthesis Report, they said that, if current emissions trends continued, average global temperatures could be expected to rise by between 1.4 and 5.8 degrees, a rate of warming "without precedent during at least the last 10,000 years". Since then, models have improved, and begun to take into account some of the positive feedback loops in the climate (such as massive methane releases from melting permafrost or warmer oceans, or releases of soil carbon from the desertification of the Amazon) - resulting in expected warmings of up to 11 degrees. We're already seeing evidence that this is occurring, and not even the IPCC can ignore it. As a result, they've now raised their baseline estimate to between 2 and 4.5 degrees (a fairly important increase by itself), and noted that higher increases are possible.
What this also means is that the "large-scale, high-impact, non-linear and potentially abrupt changes in physical and biological systems" they warned about - things like melting ice caps or a slowdown in ocean currents, are also more likely. And this means that governments have to sit up and take notice. The risk assessments that underlie greenhouse policy have so far ignored these scenarios, considering them too unlikely to be considered a basis for policy. Now they're looking a lot likelier, lending support to a precautionary approach.
12 comments:
> This is important.
hmmmm....
> So, when it says something, you expect the reality to be much, much worse.
IPCC is a scientific body - when they say it that is what it is. They ignore the wacky scenarios and many of the wacky scenarios are for massive change but that is no reason for us to think that we should "round up" the IPCC scenario - that is just ridiculous.
> expected to rise by between 1.4 and 5.8 degrees
Im not sure if you arent confusing two things here. the quotes in this range are usually temerature changes in 100 years
> resulting in expected warmings of up to 11 degrees.
changes in this range are usually related to "total burning of carbon" (ie 500 years or whatever).
> As a result, they've now raised their baseline estimate to between 2 and 4.5 degrees (a fairly important increase by itself).
do you mean they raised it from an average of 3.6 to an average of 3.25? or that they declared they are uncertain about their range of uncertainty (silly).
It would make sense however if over time the IPCC narrows it's range by rejecting various scenarios that make up it's "band of probable outcomes".
Secondly that the estimates might be going up (if that is the case) doesnt mean they will continue to do so unles somehow we presume out simplistic analysis is smarter than the IPCC's collective scientific minds.
Posted by Genius : 2/28/2006 07:08:00 PM
No upper limit. Good grief!
They don't even draw the line at xenocide or the human race exploding along with planet Earth into a thousand sorry pieces?
What about the galaxy turning to cream cheese and the Spice Girls reforming? Couldn't that be the upper limit? No? Not even that? No upper limit! Doom and chaos without end!
Thanks for the headsup!
Seriously, get your ass to http://pc.blogspot.com and get wise about the environment. This is bullcrap.
Posted by Rick : 2/28/2006 07:53:00 PM
Genius: The IPCC is a scientific body, but one limited by its political processes. It makes its decisions by consensus, which means that it can only report what the deniers will allow it to. This means a standard of proof far higher than that accepted by most scientists - and far more conservative projections as a result. Their reports are most definitely not crap - this very flaw means that their conclusions are extremely robust. However, the way in which these conclusions are ultimately decided should be kept in mind when considering whether the estimates are likely to be low or high.
(Flannery has some lovely stuff about how the IPCC works in practice. For example, the Saudis watering down the last report because they would not agree to any science which might discourage people from buying oil...)
The 1.4 to 5.8 degree figure is indeed over 100 years; that's how these estimates are normally reported. It's also across several scenarios depending on whether the level of atmospheric CO2 stabilises at double or 3.5 times the pre-industrial level. The new 2 - 4.5 degree figure is for a single scenario where it doubles. Previously for this scenario the IPCC has reported in the range of 1.5 and 4.5 degrees - so their lower limit is creeping up significantly (remember, we warmed 0.6 degrees last century, so the increase is basically saying that we'll warm at triple the previous rate rather than "merely" double it).
The 11 degree figure relates to the climateprediction.net distributed computing study published last year in Nature, again based on a doubling of atmospheric CO2 (You can read it here [PDF], BTW).
Basically, in the past the IPCC has tended to ignore variability in the models and downplay the higher estimates as outliers to give a false sense of security on how bad things could get. Better models and the growing evidence on positive feedback mechanisms means they're now saying "this is the probable range, but it could also be much worse". Whether it will be much worse will depend on how many tipping points we've already passed through...
Posted by Idiot/Savant : 3/01/2006 12:42:00 AM
> because they would not agree to any science which might discourage people from buying oil.
This is of course a ridiculous reason - but it is how science works
There are many people out there with there ego invested in proving that there is a lot of global warming happening (and they may be correct, of course). Presumably if they are doing their jobs there are a bunch of environmentalists/scientists in the room they are stopping all the low scenarios (because that would discourage petrol taxes or whatever - who cares what their exact reason is).
Hopefully in the end only the stuff that meets a minimum standard gets out. Not only that, but presumably the result cant be pulled apart in the media because it has already been pulled apart.
Anyway - I suggest academics might reject a scenario that talked about a 11 degree rise to 2100 based on historical data - infering some sort of a carbon sink or whatever. (not that i have the information to say why). those sorts of issues would come up if it was an individual experiment in an individual paper - but are jut technicalities on a study that has hundreds of simulations.
I think the "bands" and the 2100 time limit that the IPCC uses are not a perfect way to put forward the information - but in the end if anyone wants to estimate the damage they should be looking at the details anyway.
If we dealt with global warming in a rational manner (and I note that we don't) then over estimating it's effect would be just as dangerous as underestimating it.
But the scientists should not have to adjust the information to make sure they "scare the politicians to make the right decision".
Anyway, I suggest there is easily enough evidence for governments to sit up and take notice already.
Posted by Genius : 3/01/2006 07:10:00 AM
Without going to deeply into the scientific complexities ,as you have proven your scientific knowledge is limited to secondary school http://norightturn.blogspot.com/2006/02/kyoto-putting-price-on-dairy.html#comments
I will endeavour to give you some background.
Firstly the IPCC model with the 11c temp increase so widely quoted was the model used by Y Izreal from the Russian academy of science,and who is also the deputy director of the IPCC.This example was the complete ignition of the total hydrocarbon resource of the earth over a 24 hour period.This would double the Co2 content of the atmosphere and the other gases,
T raising was only if other factors.ie variables were present,the solar forcing during the sunspot cycle,high cloud cover and the reduction of UV light reception in the trotsphere etc.
That is the theoretical maximum that can be achieved!.Whilst it is possible it is not probable.
Secondly the temp and climate in the holocene 5000-6000 k was higher in Northern Europe and Eurasia.This evidendenced by the tree species and pollen that was present at this time.
Your link to the Siberian Cryosphere and west antarctic ice shelf as evidence is Rubbish.
The Russian institute for the Cryosphere made laughable the publication in the new scientist.
The top portion of the perma frost melts each year,This is part of the naturally occuring climatic cycle,the microflora then absorb CO2 and convert it to methane.
The natural laws of physics if we use a real measurement IE kelvin preclude the entire melting of the permafrost to base with a rise of the above theoretical limit.
Secondly explain how the melting of the west antarctic ice shelf can cause sea level change.There are basic natural events occuring there do you know what they are?
I think you want to outlaw the laws of physics and nature as you do not know what you are talking about.
Posted by maksimovich : 3/01/2006 11:02:00 AM
Who cares what their exact reason is? Their reasons are kind of important if you're going to allege that they're deliberately rejecting valid science. The Saudis have a very clear reason for interfering - they stand to loose a great deal of money. That's a lot more convincing than "ego".
As for tipping points, we're going to keep passing through them, since the world isn't going to make any real progress in addressing the issues in the foreseable future.
Posted by Commie Mutant Traitor : 3/01/2006 01:15:00 PM
So Icehawk you are stating that the IPCC are global warming deniers .The paper was at the COP11 Montreal conference in Novemeber.Unfortunately for experts such as you the IPCC experts confirmed the max lilit as offered by hypothesis of all the hydrocarbon global resource being extinguished as that is the obvious upper control limit.
Unfortunately for you your maths is bad as is your comprehension of the quantification of anthropogencic GHG as a percentage of total atmospheric GHG budget.
The devil is in the detail .The objective was to allow a system of differential thresholds to be prescribed.
This is all part of the work of the working group for the third assessment report.
This brings an interesting conundrum for you either the IPCC is incorrect or you are.If so, are they incorrect in all their publications,what are your hypothesis and research developmets that we can prove them wrong,.
The hypothesis excludes use of coal from antarctica and deep sea coal extraction.
Posted by maksimovich : 3/01/2006 07:14:00 PM
> That's a lot more convincing than "ego".
Cripes - you don't seem to know much about academia.
Also I note the very fact that you comment implies you are an example of basically what I am talking about.
you oppose the aspect of my comment that opposes your world view. So as long as others challenge men on the parts that challange their world view we might head towards the truth.
Posted by Genius : 3/02/2006 09:46:00 PM
Wow, looks like you No Right Turners are taking a bit of a wopping here..
Rick, The claim is that we don't know the upper limit to climate change. We just don't know how bad it could get.
So my comments about the galaxy turning to cream cheese and the Spice Girls reforming were not merely idle speculations. Shit!
Currently the greenhouse effect raises earth's temperature by about 35 degrees C above what it would be without it. And concentrations of all the key greenhouse gasses...are expected to more than double. Those gasses contribute approx 40% of the greenhouse affect...Think about that. Do the basic bloody maths."
Mathematics indeed sir. I think the answer to this is...
Unfortunately for you your maths is bad as is your comprehension of the quantification of anthropogencic GHG as a percentage of total atmospheric GHG budget.
The devil is in the detail .The objective was to allow a system of differential thresholds to be prescribed.
Apart from the (very amusing) back-firing of your own authoritive source on what you guys are saying, the above is the key point.
In economics we talk about 'constant returns to scale,' CRS. The math for CRS is very simple. It means, for example, that production output is a direct result of increasing labour input. Or for another example of CRS, the more chocolate I eat the happier I'll be.
Another concept in economics is 'deminishing returns to scale.' An example of this is the old adage 'too many chiefs, not enough Indians' or 'too many cooks spoil the broth.' Consumption of chocolate is an example of DRS because we can only eat a finite amount per period- as any fan of Monty Python would know.
Ice, if you don't see the point just yet it is this- you are assuming simple constant returns to scale in an extremely complex system of interplaying processes. Hurling twice the CO2 into the air today does not mean we're going to have half the beach-front property we had yesterday.
Posted by Rick : 3/03/2006 01:55:00 PM
Genius: this is not a case of scientists wanting to "adjust the information to make sure they 'scare the politicians to make the right decision'". This is a case of people heavily invested in global warming not happening (in that action to prevent or limit its effects would interfere with their profitability) actually adjusting the information in the opposite direction, in an effort to tone down the warnings and make it look as if everything is OK (or at least, not as bad as it really is).
There is a nice side-effect here of making the IPCC's results extremely robust, in that there's absolutely no way they can be accused of being "chicken little" - but I don't think that closing our eyes to the extent of the problem will result in good policy (any more than reacting hysterically to it will).
And despite this, yes, I think that despite all this, the evidence presented by the IPCC more than justifies action. The 2001 synthesis report (linked above) basically said "we're fucked" (in the sense that the conservative levels of climate change they are predicting will cause unacceptable levels of human suffering and economic damage). And this year's one is goign to be even worse...
Posted by Idiot/Savant : 3/04/2006 02:24:00 AM
Maksimovich: that's not the paper I am citing - as you would know if you had clicked the link.
Rick: please spare us your strawman. Icehawk is quite clear that the global climate is a chaotic system, exhibiting nonlinearity. Which is precisely the problem.
Posted by Idiot/Savant : 3/04/2006 02:51:00 AM
I/S I have already read the paper some time ago.Unfortunately the data and modelling is well out of date.It has as much relevance as a 4 year old PC magazine at the dentist.Always update and review new data and observations.
Every day new research is published most will not make the western press.80 % is not published in english.
The IPCC whilst allowing a good forum for reserch publication and investigation is limited in its criteque and review systems and still using basic premis for qualitative analysis that is flawed ,outdated,and now not scientific.
The primary quotients and model for the biomass is based on 1988 data and is 50% of the coefficients of variation and qualitative attributes.The quantitative budget changed in 1996 and has changed again in 2006.
The base model is unchanged.
Simplistic overviews are unfortunately inadequate.We know very little about the world or its inhabitants and process.
You state that it is going to get warmer.Unfortunately for your predicition it is going to get colder this year.The natural cyclical behaviour of the solar cycle and the pressure gradient equalisation always obey the laws of the Universe.
Posted by maksimovich : 3/04/2006 01:08:00 PM
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