Guest Post by Bob Tisdale
INTRODUCTION
Apparently, based initially on a 1975 “first intuition” by an economist (not a climate scientist), politicians have sought to limit global surface warming to 2 deg C above pre-industrial levels by restricting greenhouse gas emissions. To that end, those politicians created the political entity called the Intergovernmental Panel on Climate Change (IPCC), whose sole purpose is to prepare reports to support the politicians’ agendas.
Politicians from around the globe are once again gathering this year to futilely try to reach agreement on how to achieve that goal of limiting global warming to the economist-suggested limit. So, in order to increase public awareness, we’re being bombarded weekly with speculations of pending global-warming gloom and doom. One was a recent article Earth now halfway to UN global warming limit at NewScientist. It included a graph titled “Halfway to hell”, my Figure 1, prepared by chemist Kevin Cowtan. The graph showed that the values of most surface temperature reconstructions would likely rise above a 1.0 deg C anomaly in 2015.
Figure 1
AN EFFORT TO HELP NEWCOMERS UNDERSTAND
What’s novel about that graph? The anomalies (deviations from “normal”) are referenced to pre-industrial times. Global surface temperature reconstruction suppliers typically reference their anomalies to other more-recent time periods. GISS uses 1951-1980, the UKMO uses 1961-1990 and NOAA often uses 1901-2000, while the WMO recommends 1981-2010. Blogger Rob Honeycutt included that Cowtan-prepared graph in his post The 1C Milestone at SkepticalScience and recommended using pre-industrial times as references for anomalies because it was the best way to convey to persons new to global warming where “we currently are relative to a 2C rise in temperature over preindustrial times”.
Obviously, Cowtan and Honeycutt are overlooking something very important. Their graph shows that it took well over a century for global surface temperatures to reach the 1.0 deg C halfway point. Many newcomers will look at the graph and wonder what all of the hubbub is about.
Cowtan and Honeycutt needed to present something more eye-catching, more alarming, if they were going to get their message across, but they didn’t. The “Halfway to hell” graph was the only graph in the NewScientist article and Honeycutt only added to his blog post a graph of CO2 emissions for different scenarios, which is meaningless to most newbies.
The only way for them to illustrate a fast-approaching threshold would be to present climate model simulations of global surface temperatures. But, oddly, the outputs of climate models don’t appear in those articles.
PRESENTING CLIMATE MODEL OUTPUTS REFERENCED TO PRE-INDUSTRIAL TIMES WOULD LIKELY RAISE SKEPTICISM FROM NEWCOMERS
The time-series graph in Figure 2 includes 81 climate model simulations of global surface temperature anomalies for the period starting in 1880 and ending in 2059, with the modelled global surface temperature anomalies referenced to the pre-industrial times of 1880-1899. Long-term surface temperature reconstructions from GISS and NOAA start in 1880, and 2059 is the year when the last climate model reaches the 2 deg C threshold of imaginary bad things. The models are driven by historic forcings through 2005 and the forcings for the projected worst-case (RCP8.5) scenario starting in 2006. Included are 81 separate climate model runs from a bunch of different modeling groups around the globe. (The listing of the 81 climate models and runs are shown in the legend of the elongated version of Figure 2 here.)
Figure 2
The thing that stands out is the 40-year spread for the time at which climate model simulations of global surface temperature anomalies meet the 2.0 deg C fantasy-based bad-things-might-happen threshold. The slowest model to arrive there does so in 2059 and the quickest model reaches the threshold 5 years from now. Climate models aren’t very helpful when it comes to telling us when we might reach the 2.0 deg C limit.
Maybe that’s why NewScientist and SkepticalScience didn’t present climate models to the newcomers, with the model outputs referenced to pre-industrial times. While it took over a century for observed global surface temperatures to rise 1.0 deg C, the climate models are telling us that the next 1.0 deg C rise will happen in 5 to 44 years. That might be confusing to someone new to global warming. Then somebody like me would have to explain to the newcomers that climate models are not simulating Earth’s climate as it existed in the past, as it exists now, or might exist in the future.
The newcomers might then focus their attentions on 2005, because it was the last year of the hindcast. There appears to be a very large spread in modeled surface temperatures at 2005 when we reference the model outputs to pre-industrial times. And we can confirm that in Figure 3.
Figure 3
So the newcomers to global warming would see that the climate models perform pretty poorly at simulating past global warming. The global temperature anomaly in 2005 from one model is about 1.17 deg C higher than that of another. In other words, there’s a 1.17 deg C spread in the change in simulated global surface temperatures from pre-industrial times to 2005, which is greater than the 1.0 deg C observed rise shown in Kevin Cowtan’s graph (my Figure 1).
And if a newcomer was as curious as I was…and had nothing better to do…she or he just might download all of the 80+ climate model outputs of global surface temperatures with the historic and worst-case RCP8.5 forcings, with the intent of determining the models with the highest and lowest warming rates. Then that newcomer just might compare those models to the warming rate of the alarmist favorite GISS Land-Ocean Temperature Index, with the new NOAA ERSST.v4 pause-buster sea surface temperature reconstruction. See Figure 4. Note that I shifted the GISS LOTI reconstruction and climate model outputs so that the trend lines intersected with zero at 1880.
Figure 4 (I corrected the typo.)
The 0.079 deg C/decade spread in the climate-model-hindcast warming rates from 1880 to 2005 is also greater than the observed warming rate of 0.060 deg C/decade.
ONE LAST POINT
While there’s nothing wrong with presenting the change in temperature as Kevin Cowtan has done (see Figure 1), the climate science community normally relies on linear trends to express changes in a metric over time. Based on the linear trend of the GISS LOTI reconstruction, global surface temperatures have only risen 0.9 deg C since 1880. See Figure 5. It’ll be a while longer (maybe a decade, based on the linear trend from 1880 to 2014) until we reach the halfway mark of the 2 deg C threshold.
Figure 5
Just in case you’re wondering, let’s look at the linear trends of the Berkeley Earth (BEST), the Cowtan and Way, the NOAA NCEI and the UKMO HACRUT4 global surface temperature reconstructions. Only the trend-line value in 2014 of Berkeley Earth comes close to 1.0 deg C. The others show increases (based on their warming rates from 1880 to 2014) that range from 0.9 deg C to 0.85 deg C.
Figure 6
CLOSING
Using pre-industrial times as the bases for anomalies helps to illustrate something very important to persons new to global warming: climate models do a poor job of simulating past global warming. Why then should those newcomers believe the political-agenda-financed climate-model predictions of future global warming that are based on speculations about yet-to-come emissions of greenhouse gases?
SOURCES
The following are links to the data for the long-term global surface temperature reconstructions:
- Berkeley Earth
- Cowtan and Way
- GISS LOTI
- HADCRUT4
- NOAA NCEI (Click on the “Anomalies and Index Data” link)
The climate model outputs are available through the KNMI Climate Explorer.
Woah, we’re half way there
Woah, livin’ on a prayer
Take my hand, we’ll make it I swear
Woah, livin’ on a prayer
I’d like to choose 1910 as the baseline in the first graph, so that the warming is already well over 1C. So…what.
Just how many people have died because of this increase in temperature? Fewer than would have, because more people die of cold weather than warm weather.
But what about more severe storms like Katrina — it was one of the worst US hurricanes ever! It was in the top 5, but 3 of those 5 happened before 1910, and the other happened in the 1920s.
I never understood what was so magical about 2 degrees of warming, anyway. Can anyone explain what is supposed to happen if we ever reach it? Why will we avert disaster if we can limit global temperature rise to 1.9 degrees?
Unfortunately, it’s not desperation – it’s the ‘if you’re gonna lie, lie big’ method.
And can there be any bigger lie than that the source of carbon to carbon based life will ( but never has before ) destroy that life in a geological instant ?
“Halfway to hell”.
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The lowest depths of Dante’s inferno was icy:
The preindustrial LIA was about as cold as this interglacial has got:
Can anyone please explain how 7 IPCC authors can make this statement at point 20 of the latest Royal Society and NAS report? And 5 of those seven are Lead authors.
Using this info we can say that trying to mitigate their CAGW is a load of crap. In human terms “thousands of years” is a bloody long time. But do these people really believe this and if so why do all the govts claim we only have a few short years to act or else? Can anyone help me out, do we believe the 7 scientists or govt leaders? Here’s their point 20.
20. If emissions of greenhouse gases were stopped, would the climate return to the conditions of 200 years ago?
No. Even if emissions of greenhouse gases were to suddenly stop, Earth’s surface temperature would not cool and return to the level in the pre-industrial era for thousands of years.
fig9-small
Figure 9. If global emissions were to suddenly stop, it would take a long time for surface air temperatures and the ocean to begin to cool, because the excess CO2 in the atmosphere would remain there for a long time and would continue to exert a warming effect. Model projections show how atmospheric CO2 concentration (a), surface air temperature (b), and ocean thermal expansion (c) would respond following a scenario of business-as-usual emissions ceasing in 2300 (red), a scenario of aggressive emission reductions, falling close to zero 50 years from now (orange), and two intermediate emissions scenarios (green and blue). The small downward tick in temperature at 2300 is caused by the elimination of emissions of short-lived greenhouse gases, including methane. Source: Zickfeld et al., 2013 (larger version)
If emissions of CO2 stopped altogether, it would take many thousands of years for atmospheric CO2 to return to ‘pre-industrial’ levels due to its very slow transfer to the deep ocean and ultimate burial in ocean sediments. Surface temperatures would stay elevated for at least a thousand years, implying extremely long-term commitment to a warmer planet due to past and current emissions, and sea level would likely continue to rise for many centuries even after temperature stopped increasing (see Figure 9). Significant cooling would be required to reverse melting of glaciers and the Greenland ice sheet, which formed during past cold climates. The current CO2-induced warming of Earth is therefore essentially irreversible on human timescales. The amount and rate of further warming will depend almost entirely on how much more CO2 humankind emits.
Interesting to use ALL THE MODELS for SLR from the Royal Society as well. According to the models we have zip to worry about for hundreds of years. Greenland is positive for SLR but Antarctica is negative for at least 300 years. Who to believe????
http://rsta.royalsocietypublishing.org/content/roypta/364/1844/1709/F4.large.jpg
Thanks, Bob.
This global warming thing is a cult, only they know the truth. We heretics will burn first.
The notion of a tipping point is ridiculous. In fact if you look at a very long term temperature reconstruction you will see the hotter periods all plateau out at pretty much exactly the same temperature. It is astonishing how persistent this feature of our climate is. You could lay a ruler horizontally across the top of the graph and it would sit right on the top of all those plateaus. There is a clear upper bound – a place where the temperature of the planet pegs out and simply can’t go any higher. This is probably caused by some kind of phase change in the climate system occurring at that temperature – a global change to circulation patterns or similar.
There is no need to fear runaway warming. Earth simply can’t copy Venus. We are not all going to fry.
I recently canceled my subscription to New Scientist due to it’s continued non scientific ranting about Global Warming. One has to question whether anything it prints is truthful or meets the scientific standard required of an erstwhile magazine.
Bob Tisdale:
Your above essay says
More “obviously” Honeycutt, Cowtan and Honeycutt are overlooking something more important than that, and it may not be apparent to “newcomers”.
While a change in global temperature anomaly (i.e. a change in temperature difference from an average) of only 2°C is feared, global temperature changes by nearly double that during each and every year.
Global temperature rises by 3.8°C over 6 months then falls by 3.8°C over the other 6 months of each and every year while nobody notices it.
And, to date, nobody has provided any evidence and/or credible explanation of why a 2°C rise in global temperature anomaly would have much more harmful effect(s) than the 3.8°C rise in global temperature that occurs during each year.
Richard
While this non-optional annual cycle is far too little appreciated , I don’t understand a +- 3.8c variation over the annual cycle . My computation gives +- 2.3 degree variation in our equilibrium temperature from our peri- to ap-helion . Do you have a reference ?
Bob Armstrong:
I wrote:
You have responded saying
That is wrong on two counts.
Firstly, I did NOT say there is “+- 3.8c variation over the annual cycle”.
I said “Global temperature rises by 3.8°C over 6 months then falls by 3.8°C over the other 6 months of each year”, and that is a variation of +-1.9°C around an average value over the annual cycle.
Secondly, the observed variation I mentioned derives from the Northern Hemisphere (NH) being covered by more land than the Southern Hemisphere (SH). And throughout the seasons land changes temperature more than water. When it is summer in the NH it is winter in the SH and vice versa, but global temperature is the average of NH and SH temperatures.
The effect of different coverage by land in the hemispheres is sufficiently large that it
(a) negates the global temperature variation from the varying distance from the Sun
and
(b) provides the observed variation of +-1.9°C around an average value.
The matter is discussed in many places including here
http://judithcurry.com/2013/12/26/seasonal-radiative-response/
and its references.
The important point is that global temperature rises by 3.8°C (i.e. nearly double 2°C) over 6 months of each and every year while nobody notices it.
Richard
Richard , I see : +- 1.9c . I was catching up on a weekend+ of emails , but I do think you stated the cycle in a somewhat odd way .
However , , the annual cycle must contain the effects of both the 4.6c variation in insolation from peri- to ap- helion and the hemispheric asymmetry . I see Chief Hydrologist brings up this component in his comments on the JudithCurry.com post .
I don’t find a value of +- 1.9c at all surprising , but this discussion highlights the lack I see of a basic text presenting all these very basic facts in the analytical quantitative manner of classical physics .
Of course the reason no one is aware of this variation is that it’s not observable at any one place , only when you are able to see the whole . At any one place , all you see is your particular diurnal and seasonal variations which swap even these effects .
I can’t help thinking that if you took a poll in the average street, asking people by how much the temperature had risen over the last century almost all would say they didn’t know. Most of the rest would guess at a figure several degrees out from even the most alarmist estimate.
They’d be astonished at how small the figure is that all the fuss is about.
When I tell them the rise is only 0.7 to 0.9C, most of them accuse me of lying.
the pro climate change people shew the temperatures towards the ipcc graphs they are stupid sciencetints. the temperature curve is going sideways why cannot you see this in the data to corrupt.
buckwheaton August 14, 2015 at 5:22 am
Trying to define an “optimum” climate for Earth is like eugenics for Nazis. Why? Because different organisms are better suited to different conditions, just like different people may have better survival characteristics for different conditions.
There is no Ubermensch, because the superior individual can be defined as superior only under some specific set of conditions. The strength of a species is its diversity. That means some subpopulation may survive even if most of the population perishes when conditions change. And for Earth, its strength is the diverse network of species able to expand in to niches newly created as conditions change.
There can be an optimum climate only for some collection of organisms. There would be a different climate optimum for another collection of organisms.
Now which organisms do you favor for your optimum? Why should this current climate be considered the best? If not this one, which one? And why should conditions stay the same? Maybe we have the collection of organisms we have in the current distribution precisely because conditions have changed, and static conditions would lead the biosphere to another distribution of organisms altogether. But so might changing conditions. The point is, the Earth is alive, and to expect is to stay the same is an idea based on ignorance.
Actually, static conditions would lead to a far fewer, and more vulnerable, collection of species. Without a dynamic climate, earth would likely be lifeless. Examples abound in just our solar system.
Change is constant, static is death. Yes, it is. So much for the current conception of ‘sustainable’, which is paralytic.
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“Apparently, based initially on a 1975 “first intuition” by an economist (not a climate scientist), politicians have sought to limit global surface warming to 2 deg C above pre-industrial levels by restricting greenhouse gas emissions. ”
This is only the marketing ad to make the thing look legitimate . The real goal is to get $100 BILLION /year for United Nations by 2020 and every year there after . The secondary goals are world wide carbon tax or cap and trade indirect tax for the various governments that can be raised at will and unlimited free money and subsidies and new business for the green industry and the ” it is worse than we thought” alarmist scientists and universities. This is a billion dollar / day industry now that thrives and lives on free money.
Sadly, all the best science in the world about what may be true or what may be not true about climate change is now totally irrelevant. The global warming alarmists are not interested in truth. They are only interested in data they can cherry-pick to support the supposition that CO2 from human activity is causing catastrophic global warming and is the key driver of climate change. It is all political. It always was all political. The following video demonstrates how this global warming scare evolved into a political issue:
Nothing is going to get in the way of the United Nations’ goal in Paris this December of achieving an international agreement to control fossil fuel energy use, and eventually ban it by 2100. These people will lie, mislead, deceive and persecute people to get their way. These people are using climate change as a stepping stone to rid the world of capitalism, democracy, freedom, the market economy and prosperity, to replace it with the UN’s sustainability model (AGENDA 21) and enforce the ambitious, arrogant, and unscrupulous ideology of environmentalism.
“Halfway to Hell” is misleading in another way. First, it implies that the threshold in question is some kind of point beyond which we are, well, in hell: things are really, really bad. But that’s not true. Near as I can tell reading studies which attempt to quantify all alleged impacts together, the 2 degree threshold is the point at which warming ceases to be beneficial on net. Second, reading those studies, they refer to 2 degrees relative to the present, *not* relative to the preindustrial period. Both such facts would, if taken into account, seriously undermine “the narrative” however, and as such they cannot be spoken of, instead a dishonest picture of their own present understanding has to be painted.
My memory, too. The 2 degree C guess was when the possible drawbacks of global warming exceed the benefits of longer growing seasons, less cold winters, etc. We’re not “halfway to hell” when we get 1 degree warmer then either now or a century ago.