On WUWT there is an article by Christopher Monckton (archived here). It's a short article (for him), in which he fudges numbers and mixes up concepts. Anthony wrote what Roy Spencer excitedly thinks is a very clever headline: 2°C or not 2°C–that is the question. Is it the question or is the question something else? It turns out the question was something else - and the answer at WUWT was wrong as usual.
The article starts with a graphic from an old slideshare presentation from Jonathon Kooney. A slide which Mr Kooney dropped from his later presentations on climate change, possibly because it was hard to make sense of it. The slide was based on the 2009 paper by Malte Meinshausen and co: "Greenhouse-gas emission targets for limiting global warming to 2°C".
Staying within the CO2 emissions budget
As stated in the abstract of Meinshausen09:
Limiting cumulative CO2 emissions over 2000-50 to 1,000 Gt CO2 yields a 25% probability of warming exceeding 2°C—and a limit of 1,440 Gt CO2 yields a 50% probability—given a representative estimate of the distribution of climate system properties. As known 2000-06 CO2 emissions were ~234 Gt CO2, less than half the proven economically recoverable oil, gas and coal reserves can still be emitted up to 2050 to achieve such a goal.
Recent G8 Communiques envisage halved global GHG emissions by 2050, for which we estimate a 12-45% probability of exceeding 2°C—assuming 1990 as emission base year and a range of published climate sensitivity distributions. Emissions levels in 2020 are a less robust indicator, but for the scenarios considered, the probability of exceeding 2°C rises to 53–87% if global GHG emissions are still more than 25% above 2000 levels in 2020.The authors say that from 2000 to 2006 there were 234 Gt CO2 emissions. From 2007 to 2013 there was another 236 Gt, which makes it 470 Gt. Last September it was estimated that at least 40Gt would be emitted in 2014, so by 2020 it's probably reasonable to assume there'll be another 280Gt, which would add to 750 Gt from 2000 to 2020. This leaves just 250 Gt to keep within the 1,000 Gt limit and a 25% probability of exceeding 2°C. If emissions were held steady at current emissions (2014), then that would leave around 6-7 years after which we'd need to drop immediately to zero emissions. In other words we could emit 40 Gt a year until August 2026 and then stop all emissions completely. Jumping from 40Gt / year to zero is completely unrealistic, so we've got to phase down immediately - starting now.
If we want to toss the dice and gamble that 1,440 Gt would give us a 50:50 chance, then we can gamble on another 18.8 years - to around 2039. At that time we'd have to stop all emissions just for a 50:50 chance of warming to 2°C.
Below is Figure 3 from the paper, showing the probability of staying below 2°C for different cumulative emissions from 2000:
|Figure 3 | The probability of exceeding 2°C warming versus CO2 emitted in the first half of the twenty-first century. a, Individual scenarios’ probabilities of exceeding 2°C for our illustrative default (dots; for example, for SRES B1, A2, Stern and other scenarios shown in Fig. 2) and smoothed (local linear regression smoother) probabilities for all climate sensitivity distributions (numbered lines, see Supplementary Information for data sources). The proportion of CMIP3 AOGCMs26 and C4MIP carbon-cycle8 model emulations exceeding 2 uC is shown as black dashed line. Coloured areas denote the range of probabilities (right) of staying below 2 uC in AR4 terminology, with the extreme upper distribution (12) being omitted. Total CO2 emissions already emitted3 between 2000 and 2006 (grey area) and those that could arise from burning available fossil fuel reserves, and from land use activities between 2006 and 2049 (median and 80% ranges, Methods). Source: Meinshausen09|
In case you are wondering about time frames of warming, the authors state:
We chose the twenty-first century as our time horizon, as this time frame is sufficiently long to determine which emission scenarios will probably lead to a global surface warming below 2°C. Under these scenarios, temperatures have stabilized or peaked by 2100, while warming continues under higher scenarios.In other words, as long as we keep to the budgets and cut emissions so that we stick below 2°C of warming, it will all happen this century and then taper off. If we don't, then it will keep getting hotter this century and beyond. Here's a chart from the paper, showing our temperature options:
|Figure 2 | Emissions, concentrations and twenty-first century global-mean temperatures. c, median projections and uncertainties based on our illustrative default case for atmospheric CO2 concentrations for the high SRES A1FI21 and the low HALVED-BY-2050 scenario, which halves 1990 global Kyoto-gas emissions by 2050. Source: Meinshausen09|
We can choose to limit the rise in global surface temperature to 2°C or a bit more, or we can choose to heat up the world to 5°C, 7°C and more.
Christopher Monckton fudges methods and data
I chose that paper because that's the one that WUWT chose to illustrate. Anthony Watts claimed:
This note by The Viscount Monckton of Brenchley uses methods and data exclusively from mainstream climate science to constrain the interval of 21st-century global warming.
Did he use methods and data exclusively from mainstream climate science? Of course not. And who believes anything they read at WUWT anyway. Here is what Christopher did and claimed.
He wrote about climate sensitivity and put up lots of numbers. You wouldn't know from what Christopher wrote, but in the IPCC's AR4 report, the best estimate for climate sensitivity was given as "about 3°C" (SPM p12), while in AR5 no best estimate was provided.
Christopher decides that climate sensitivity in AR5 is 2.2°K. He pulled that number out of his hat. (AR5 states climate sensitivity lies between 1.5°C and 4.5°C, with no "best estimate".) Christopher then arbitrarily halved his 2.2°K to get 1.1°K, claiming that "only half of equilibrium warming will occur in the first 100 years after a forcing". Never mind that we've already had 150 years of forcing, and more than 60 years where human activities accounted for all of the net forcing. He then put "the remainder in the following century, by which time fossil fuels will approach exhaustion".
How convenient. You'll no doubt have noticed that not only did Christopher fudge all the numbers and time frames, he also jumped from climate sensitivity to temperature rise. He assumed one of the following:
- there won't be any more CO2 added to the air beyond 560 ppm, or maybe
- after 560 ppm CO2, burning fossil fuels will no longer release CO2, or maybe
- after 560 ppm, 100% of the CO2 emitted from burning fossil fuels will be absorbed by plants and oceans.
Even if half the emissions continue to be absorbed by the oceans and plants then atmospheric CO2 will continue to rise as long as we pour it into the air. And the chances of half of it continuing to be absorbed by surface processes gets less the more we emit, as discussed in the recent paper on oceans.
Christopher continued to wrongly conflate climate sensitivity with maximum warming, and wrote:
Remaining warming to equilibrium at 2.2 K above today would be spread over the subsequent 1000-3000 years (Solomon et al., 2009), allowing plenty of time for adaptation.
What Christopher Monckton got wrong
All these assumptions of Christopher's are wrong or questionable:
- Christopher asserted that climate sensitivity is 2.2°K. It could be anywhere from 1.5°K to 4.5°K or higher.
- Christopher wrongly assumed we will stop emitting CO2 when atmospheric concentration reaches 560 ppm. Since it's already more than 400 ppm, we'll have our work cut out over the next few years to get it to remain under 560 ppm
- Christopher wrongly asserted that the temperature will only go up by half the end amount this century - that's not necessarily correct as can be seen by the chart above. It depends on how much CO2 we add to the atmosphere.
- Christopher wrongly asserted that fossil fuels will run out before we reach a danger point. That's not correct either. Not by a long shot.
On the point of fossil fuel reserves, below is what was stated in Meinshausen09. Remember that to keep the risk of getting above 2°C to even 25%, the budget from 2000-2050 is just 1,000 Gt of CO2, and we've already spent more than half that budget.
We explored the consequences of burning all proven fossil fuel reserves (the fraction of fossil fuel resources that is economically recoverable with current technologies and prices: Fig. 3b and Methods). We derived a mid-estimate of 2,800 Gt CO2 emissions from the literature, with an 80%-uncertainty range of 2,541 to 3,089 Gt CO2. Emitting the carbon from all proven fossil fuel reserves would therefore vastly exceed the allowable CO2 emission budget for staying below 2°C.
From the WUWT comments
I didn't see anyone notice that Christopher assumed that we will stop emitting CO2 once it reaches 560ppm. Nor did I see anyone query his assumption that fossil fuels will run out before we get to 560 ppm CO2. I don't know if there is anyone left reading WUWT who has a brain or knows how to use it. Maybe the WUWT fans who use a few of their brain cells (are there any) don't bother reading articles by Christopher Monckton.
philincalifornia has noticed the condescending attitude of normal people towards the wilfully ignorant denialati, and that to burn up the planet is rightly framed as a moral issue:
July 4, 2015 at 11:20 am
Climate Policy – the greatest parasitic infection of humans ever. Not just in the minds of the pompous prats running around pretending to be our morally superior betters, but in the destruction of wealth and well-being for ALL of humanity.
Expat wants the oil and coal barons to keep control over carbon. He's probably a serf by nature:
July 4, 2015 at 6:35 pm
Control of Carbon is the key to control – of us. A socialist wet dream.
Glenn999 is barely intelligible. I think he's arguing that an ice age cometh:
July 4, 2015 at 4:25 pm
What would be worse: to continue down the current path to insanity, with the resultant deaths caused by green policies, or,
to experience real solar-induced climate change that would immediately force people to reconsider CO2 reduction schemes?
Perhaps the survival instinct would kick in, and with this newly awakened awareness, humanity would embrace reality-based solutions. I think probably less dire for many more.
Streetcred is impatient for the decades to roll on:
July 4, 2015 at 8:18 pm
I’m still waiting 2C … not much happening.
Louis Hunt doesn't read climate science. He seems to have picked up bits of nonsense from denialist interpreters of deniers' interpretations. (No, there won't be "runaway warming" on Earth and no scientist would claim that.)
July 4, 2015 at 11:41 am
When Gore and Hansen first began preaching against the sins of global warming, it was not just the warming caused by more CO2 that would be a problem. It was mostly the warming caused by positive feedbacks that would doom us all. The feedbacks, we were told, would eventually cause “runaway global warming” that would “boil” the oceans and turn us into Venus. But evidence of those positive feedbacks has yet to materialize. What steadily increasing CO2 over the past couple of decades, with very little warming, has shown us is that the feedbacks have not been positive. If anything, they are negative because we have not experienced the amount of warming that CO2 alone, without feedbacks, should produce. It was my impression that the main reason 2 degrees of warming would be dangerous was because of the positive feedbacks that would pile on later. So, if those positive feedbacks do not occur, why would another degree or two of warming be a problem?
Roy W. Spencer gets over-excited by the headline:
July 4, 2015 at 12:13 pm
OMG! I love the title!!
Monckton of Brenchley excels at making up stuff:
July 4, 2015 at 12:44 pm
The key point about this posting is that it uses exclusively mainstream climate science from “official” sources. And yet it shows just 0.6 C warming this century, or 1.0 C at most. It will be intriguing to see whether the usual suspects are able to show that there is anything materially wrong with the argument and, therefore, with the conclusion.
co2isnotevil is perpetually amazed. He or she has a serious case of Dunning-Kruger-itis:
July 4, 2015 at 1:36 pm
A time constant greater than a century doesn’t make sense either. If the time constant was that long, we wouldn’t be seeing any differences between summer and winter, even at the poles where its dark for half the year. The satellite data tells us that the average ocean temperatures exhibit a seasonal variability of about 4C in the S hemisphere and about 5C in the N hemisphere for a net change of 1C p-p during a year. This indicates ocean time constants on the order of a year or two, but not centuries. The ebb and flow of ice is slower, but if you calculate the effect if all the ice was permanently gone, it would only be enough incremental input power to support about half of the global 3C rise claimed just from doubling CO2. Keep in mind that 2/3 of the ice is covered by clouds and the decrease in surface reflectivity has no effect.
It never ceases to amaze me how once they get an answer they want to see, they can no longer see the errors that led them to the wrong answer.
ristvan thinks there'll be a stadium wave of cooling, triangulated, despite the fact that it looks to be already disproven:
July 4, 2015 at 2:36 pm
I think your range is right. Three reasons. First, stadium wave and Arctic ice cycles both suggest a continuation of natural variation ‘cooling’ into the 2030’s. Too much to catch up thereafter. Second, the solar cycle quiet sun phase we seem to be entering. Third, atmospheric CO2 cannot double from here to 800ppm by 2100. FernandoLeanme is right. Gaia’s Limits contains exhaustive arguments and evidence from many sources. Oil, quite solid. Coal, fairly solid. Natural gas most uncertain, but then NG combustion emits the least CO2. So only some fraction (2/3? 3/4?) of the energy budget 70 year TCR of ~1.3 could happen by 2100, and that not via the linear 1%/year to doubling in 70 years that TCR assumes. So worst obswrvational case is TCR 1.3 times 0.75 CO2 = 0.97C by 2100. Hope these alternative perspectives will strengthen and enrich your conclusion by trianglation from different angles. Regards
craigm350 is convinced that its impossible to know anything about climate. It is all too uncertain. Nevertheless he is absolutely certain (p=0.99) that there is nothing to be concerned about. In other words he thinks our climate future is simultaneously absolutely certain and absolutely uncertain.
July 4, 2015 at 4:27 pm
SJW’s pull arguments out of their backsides. I see little evidence climate scientists do anything more, so arguing about ECS – angels on a pinhead – is little more than entertainment. We don’t know. We have far too crude measurement sticks. The amount is smaller than we can hope to measure (‘confidence’ in the existence of angels aside). All we do know is there is little if nothing to concern ourselves with. Never has. Never will. Can we move on to more serious things now than pointless philosophical arguments with the terms set by those in the pay of setting the parameters of said debate (about angels)? We will never burn – on this earth at least (fair skin expected). I hope we don’t freeze from ignorance.
References and further reading
Meinshausen, Malte, Nicolai Meinshausen, William Hare, Sarah CB Raper, Katja Frieler, Reto Knutti, David J. Frame, and Myles R. Allen. "Greenhouse-gas emission targets for limiting global warming to 2 C." Nature 458, no. 7242 (2009): 1158-1162. doi:10.1038/nature08017 (pdf here)
Schmidt, Gavin, and David Archer. "Climate change: Too much of a bad thing." Nature 458, no. 7242 (2009): 1117-1118. doi:10.1038/4581117a (pdf here)
Hit the brakes hard - RealClimate article about the above, plus more