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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Recommended supplemental reading:

The Next Great Global Warming ‘Hiatus’ Is Coming! by Ethan Siegel, Starts with a Bang, Forbes, Mar 16, 2016

One Planet Only Forever at 00:35 AM on 23 March 2016

Current record-shattering temperatures are shocking even to climate scientists

bozzza@5,

I am skeptical of the marketplace 'reacting to any developing better understanding of what is required to advance all of humanity to a lasting better future'.

The way the 'marketplace' has reacted to the better understanding of the unacceptability of already fortunate people continuing to get benefit from the burning of fossil fuels is clear proof that the 'current popular and profitable for some' marketplace driven by popularity and profitability is in many cases a destructive barrier to the advancement of humanity.

The biggest problem is clearly the way that misleading marketing can promote less acceptable action plans that are 'temporarily' more profitable and rewarding for a portion of the entirety of humanity (the entirety includes future humans) for as long as they can be gotten away with.

Less acceptable is almost always quicker and cheaper (or less acceptable choices like pursuing violent actions like invasion or promoting rebellion in other regions being potentially more successful actions). Therefore, the most profitable and popular activity 'winning in the marketplace' is likely to be the least acceptable activity that can be gotten away with. And misleading marketing is a proven significant factor in prolonging and even expanding activity that can be understood to not be advancing humanity to a lasting better future for all on this or any other amazing planet (political misleading marketing clearly being potentially more damaging than commercial misleading marketing, but commercial misleading marketing paired with misleading political marketing being clearly being the greatest weapon of mass destruction ever created).

Humanity's only real future is through figuring out how all of humanity can live decently as sustainable parts of the robust diversity of life. Humans trying to thrive or survive solely through technological advancement succeeding in the marketplace of popularity and profitability clearly have no future.

Faith in the 'marketplace' advancing humanity to a sustainable better future is obviously misplaced, especially when misleading marketing promoting self-interest can succeed in drumming up popular support against the advancement of humanity.

The global warming case is only one of many clear cases of the obvious fatal failings of the 'fabled invisible-handed marketplace drive by self-interested and likely misleading pursuers of what they want to get away with' that is promoted as something that must be revered, something that can never be questioned no matter how much evidence there is proving that believing in it is foolish.

scttharding5 at 00:04 AM on 23 March 2016

Current record-shattering temperatures are shocking even to climate scientists

I think that the current surface temperature spike that has been caused by AGW and a strong El Nino is an opportunity for the scientific community to convince many people here in the U.S. that climate change is a real threat. However, caution is required due to the probability that surface temps over the next few years will be somewhat lower than 2015-2016. Scientists and activists should use this time of heightened interest and awareness to explain to the general public the importance of ocean warming and overall heat content.

knaugle at 22:36 PM on 22 March 2016

2016 SkS Weekly Digest #12

#1Then again, the cartoon satirizes climate deniers who no matter what happens will always say something like "Well, I expected that, no big deal"

CBDunkerson at 21:59 PM on 22 March 2016

Current record-shattering temperatures are shocking even to climate scientists

dagold, the problem is that we have a much clearer picture of the, for example, 1951-1980 baseline, than we do of the 'pre-industrial' value... especially given that 'pre-industrial' itself is an inexact term.

Given that 'pre-industrial' in this case really means 'before atmospheric CO2 levels started climbing rapidly' I'd think that would be the place to start. Between 1800 and 1850 atmospheric CO2 went from ~280 ppm to ~288 ppm. That's actually a fairly rapid increase rate in comparison to past events, but nothing compared to the rate since 1850. Thus, that time period or a little earlier would seem to be the proper baseline. Unfortunately, our instrumental temperature record prior to 1850 is extremeley limited. That time also happens to coincide with the 'little ice age', when there was some degree of cooling (particularly in NW Europe where most of the few temperature records we do have were taken) likely due to low solar output and/or vulcanism. Hence the difficulty of getting a clear 'pre-industrial baseline'.

Still, I agree. The various climate summits should long ago have settled on some reasonable standard estimate for the 'pre-industrial' temperature. Without that, the 'limits' they seek to avoid cannot even be computed... by a few outlier accountings, 1.5 C had already come and gone before the Paris pledge to try to avoid it.

barry1487 at 20:23 PM on 22 March 2016

Global Warming Basics: What Has Changed?

I read his first few yesterday and responded to them yesterday. Don't have a photographic memory, unfortunately.

Tom Curtis at 19:12 PM on 22 March 2016

Global Warming Basics: What Has Changed?

barry @16, as you have now read his billev's first comment, and will get to his second and third comments shortly, no doubt, you will be aware that billev is not in fact open to persuasion.

barry1487 at 18:38 PM on 22 March 2016

Global Warming Basics: What Has Changed?

Ah, billev, I re-read your first comment.

There were pauses in temperature rise from about 1880 until about 1910 and from about 1945 until about 1974 and now since about 2002

The mean trend estimate since 2002 is positive (but see below). You can check for yourself at this easy-to-use app on the web. Just type 2002 in the start year box, select whichever data set and hit 'calculate'.

www.ysbl.york.ac.uk/~cowtan/applets/trend/trend.html

The uncertainty is larger than the trend, but that doesn't mean there isn't one. It does mean that the time-period is too short to confidently claim a pause, cooling, warming or whatever. Way too short. You need longer time periods for this data. 30 years is a good minimum standard.

barry1487 at 18:27 PM on 22 March 2016

Global Warming Basics: What Has Changed?

he is too arrogant to consider the possibility that it might be he who is mistaken.

Not necessarily. He declared his lack of expertise. His statements seem confident, but that doesn't mean he's close-minded. Let's reserve judgement.

barry1487 at 18:24 PM on 22 March 2016

Global Warming Basics: What Has Changed?

billev,

I think that use of the period 1974 to 2002 compared to the period 1911 to 1945 would be a more appropriate comparison rather than 1975 to 2015.

Why? The more data, the less uncertainty. What's so important about 2002? Do you think it marks a transition point or something?

Tom Curtis at 16:05 PM on 22 March 2016

Global Warming Basics: What Has Changed?

billev @11 states that:

"I also think that years that feature unusually large temperature spikes either up or down associated with short term climate events should be ignored."

It is very obvious, however, that he does not practise it. For example, if we determine the GISSTEMP trend from 1910-1974, and take the residuals to that slope over the entire record, there is an obvious "unusually large temperature spikes ... associated with short term climate events":

The spike spans only a single decade(1936-1946) so is obviously short term. Its cause is likely primarilly an artifact of the large change in SST measurement methods coupled with larger changes in typical ocean routes (and hence areas of the ocean SST frequenlty measured), but the large 1939-1942 El Nino was no doubt also a major contributor. (A greater than expected forcing from black carbon cannot be excluded either). Although I used GISSTEMP, the spike is also evident in the NOAA record which billev prefers.

Of course, had the spike been excluded, as billev claims should be done with such spikes, his temperature record would be a slight downward trend from 1880-1910, reversed by a slight upward trend from 1910-1970, and a strong upward trend thereafter.

Why 1970 and not 1974? Well, 1974 was the start of a very strong La Nina of record breaking length, and hence of a large downward temperature spike such as he says should be ignored. Rather than ignoring it, however, as with 1945, he turns it into a breakpoint.

Even worse is his insistence on a breakpoint in 2002. As it happens, a 1974-2002 trend is less than the 1974-2003 trend, less than the 1974-2005 trend, less than the 1974-2006 trend, and even less than the 1974-2007 trend. Only for years after 2007 is the trend from 1974 less than that from 1974-2002. Why then is 2002 chosen in preference to 2007 and the breakpoint? As it happens, 2008 was a strong La Nina year (along with having the lowest solar activity since 1910). And 2012 had the second strongest La Nina year since 1876 when the SOI records begin. If he truly excluded "unusually large temperature spikes", billev would have needed to exclude 2008, 2012 and 2013 from the data - something using a 2007 breakpoint makes altogether to obvious. So instead he shifts the breakpoint back to 2002, but must still retain the years he claims should be excluded in order to get his "pause".

Without those three strong La Nina years, there is no pause in the 21st century. Indeed, even including them and the (so far) tied eigth strongest El Nino on record results in no pause, with the cherry picked 2002-2015 trend being nearly the same as the cherry picked 1910-1945 trend. Indeed, that was the point of billev's comment. He needs to exclude 2015 to maintain a case, so he drops in a throw away rational to do so, while not noticing how damaging it is to his case.

billev states "I am neither a scientist or a statistician", and as can be seen above, nor does he have more than a superficial knowledge of the data. And on this foundation of expertise, he disputes the conclusions of people who are scientists and statisticians, and how know the data like the back of their own hands. Despite that, he is too arrogant to consider the possibility that it might be he who is mistaken.

ubrew12 at 14:35 PM on 22 March 2016

Tracking the 2°C Limit - February 2016

Hank@23 said: "I started engineering long before computers when everything was done with hand calculations" Sorry, I had no idea! I assumed I was talking with a modern stamp-product of the STEM system.

I'm a lowly thermal engineer. However, primarily in spacecraft (of which Earth is such) and so the entire 'controversy' over a CO2-induced radiative imbalance over our spacecrafts heat-rejection capability quite frankly has been 'cramping my 88*ss' for 20 years now. It's time to let Physics tell its story, and believe the story its telling.

bozzza at 12:43 PM on 22 March 2016

Current record-shattering temperatures are shocking even to climate scientists

Coral Bleaching takes only a few months to be a harbinger of bad!

Market forces will react if necessary!!

dagold at 09:51 AM on 22 March 2016

Current record-shattering temperatures are shocking even to climate scientists

Knaugle - still, you raise an excellent point, imo. The various baselines (1951-1980, 1981-2010, etc.) do a great disservice to getting the idea of 'total warming' across. The total warming, including all the intentions set in Paris, are keying of a pre-industrial baseline which is, of course, lower than ANY of the later ones. I'm sure, to the average person, a reportage of, say, 1.35C above 1951-1980 appears as a "total warming" of 1.35C. But, as this article points out, it is much worse than that. Frustrating.

Mal Adapted at 09:46 AM on 22 March 2016

Lots of global warming since 1998

From a guest post on RealClimate a while back, by Stephan Lewandowsky, James Risbey and Naomi Oreskes, Hiatus or Bye-atus?:

To date, research on the “pause” has addressed at least 4 distinct questions:
1. Is there a “pause” or “hiatus” in warming?
2. Has warming slowed compared to the long-term warming trend?
3. Has warming lagged behind model-derived expectations?
4. What physical mechanisms underlie the “hiatus”?
Those questions are not only conceptually distinct, they also involve different aspects of the data and entail different statistical hypotheses.

Answering the first question requires careful construction of the null hypothesis being examined, leading directly to the second question. That was addressed in another RC post, by Stefan Rahmstorf: Recent global warming trends: significant or paused or what? Using the appropriate statistical technique of "change point analysis", Stefan showed there was no statistically significant divergence from the long-term warming trend based on GISTEMP data, and tamino showed no statistically significant divergence in any the commonly-used datasets .

The answer to the third question, by working climate scientists as well as AGW-deniers, is usually 'yes', leading naturally to the fourth question. The best peer-reviewed response, IMHO, is the 2014 Nature Geoscience Commentary by Schmidt et al., Reconciling warming trends, discussing how the CMIP family of models can better resolve short-term “noise” to forcing by greenhouse gasses, solar irradiance, ocean circulation, and anthropogenic and volcanogenic aerosols. This is science working as expected.

Rob Honeycutt at 07:10 AM on 22 March 2016

Tracking the 2°C Limit - February 2016

Hans... I'm not really so sure La Nina is going to come save us. The ONI figures dropped back down to -1.6 after the 1997/98 El Nino, but if you look at the 2nd or 4th figures in this post, temps only dropped back down to the long term trend. I would expect something similar for this El Nino.

Glenn Tamblyn at 07:02 AM on 22 March 2016

Current record-shattering temperatures are shocking even to climate scientists

A coral bleaching event on the GBR isn't just likely, it has started. The question now is whether the term 'massive' will apply.

Hans Petter Jacobsen at 06:45 AM on 22 March 2016

Tracking the 2°C Limit - February 2016

I really liked the 'Tracking the 2 °C Limit' plot the first time I saw it, and I therefore generated a similar plot for my blog. I still like the plot, but I have a couple of comments on it.

The plot and the text in the blog post focus on the 'Current 12 months average' and on the last month. If we focus too much on the warming in the current El Nino phase, we have to accept that the contrarians will focus on the cooling in the next La Nina phase. These ups and downs in temperature are caused by natural climate variability. Our concern must be the long term warming, and we should therefore concentrate on the long term trend line.

My other comment is that the plot may give the impression that we may wait some years, maybe even a decade, before harsh measures to reduce the emissions must be implemented. This is because the temperature increases rather slowly due to the inertia in the climate system. Despite more than one hundred years with man-made carbon emissions, the long term temperature trend has increased by only 1 °C. In the next decade it will probably rise by another 0.2 °C, and there is still 0.3 °C left before the 1.5 °C limit is reached. We get a more grim and realistic view on the situation if we focus on the carbon emissions and on the carbon budgets. If the current carbon emissions continue as they were in 2014, the IPCC carbon budget for 1.5 °C warming will be exhausted in six years.

I have written more about this on my blog.

KR at 06:08 AM on 22 March 2016

Global Warming Basics: What Has Changed?

billev - Short term variations (such as ENSO and volcanic activity) are part of the data as well, and if you are actually trying to establish the long term trends they have to be accounted for in some fashion or another.

2002 to now (just 13-14 years) is far too short for statistical significance given the underlying climate trends and short term variability; I'm afraid your claims in that regard aren't supported by the numbers.

As to the amount and effect of CO2, I suggest reading the SkS article on the 'CO2 is just a trace gas' denial myth - doubling one of the few IR active long term greenhouse gases certainly has an effect. Arguments from personal incredulity (your 'difficult time believing') are a farily common logical fallacy.

rkrolph at 04:51 AM on 22 March 2016

Global Warming Basics: What Has Changed?

billev-

You admit that there is much you don't understand so that's a start. Just because something doesn't make sense to you doesn't mean it isn't real. If you are really serious about climate science, you should try to educate yourself and understand what the scientists are saying and why. Then you can come back and ask intelligent questions about the subject once you are more informed.

billev at 03:55 AM on 22 March 2016

Global Warming Basics: What Has Changed?

I am neither a scientist or a statistician so there is much I do not understand. In my original post i said that the NOAA temperature chart shows an overall upward trend in temperature. I think that use of the period 1974 to 2002 compared to the period 1911 to 1945 would be a more appropriate comparison rather than 1975 to 2015. I also think that years that feature unusually large temperature spikes either up or down associated with short term climate events should be ignored. I have a difficult time believing that carbon dioxide at one part in 2500 parts of atmosphere has any role that influences the global temperature. There is just not enough there there.

Moderator Response:

[TD] Please read "CO2 Is Just a Trace Gas."

knaugle at 01:30 AM on 22 March 2016

Current record-shattering temperatures are shocking even to climate scientists

Of course on closer reading I missed the answer to my question. Sorry.

knaugle at 01:27 AM on 22 March 2016

Current record-shattering temperatures are shocking even to climate scientists

So when climate scientists and policy makers say the target beyond which we are likely to see more worrisome effects is +2°C, what is that in relation to? I had thought it was the 20th century average. So if NASA reports we are +1.35C relative to 1951-1980, doesn't that mean we are even higher relative to the other baseline? Regardless, it is more a semantic question than anything.

KR at 23:05 PM on 21 March 2016

How we know the greenhouse effect isn't saturated

ConcernedCitizen - Are you asking about 'latitude' or 'altitude'? The latter would make sense given previous exchanges, the former not so much.

CO2 is indeed radiating from a higher (and hence cooler) altitude than it did before the Industrial Revolution, the spectra of emissions at the top of the atmosphere (TOA) has been observed by satellites to have changed just as expected, the tropopause has risen several hundred meters, etc etc etc. And the explanation for it is indeed part of the OP, not to mention many of the comments made in this thread and others.

Therefore your comment above is simply nonsense, and the article continues to hold true to both theory and data. You've made a series of such comments, and have been pointed to the literature and the physics demonstrating why you are incorrect. I would suggest you take advantage of such pointers, and educate yourself.

barry1487 at 21:33 PM on 21 March 2016

Global Warming Basics: What Has Changed?

Thanks mod. I hoped the insert format would do that auto. Width=500 for next time.

Moderator Response:

[RH] No problem!

ConcernedCitizen at 20:33 PM on 21 March 2016

How we know the greenhouse effect isn't saturated

If no one can explain why CO2 is radiating from a higher lattitude then can we assume than that it isnt and that the article is false?

barry1487 at 17:36 PM on 21 March 2016

Global Warming Basics: What Has Changed?

Slight amendment:

"If one wants to claim that there is some kind of mulitdecadal cycle in climate evolution, one has to deterine a physical mechanism. Attempts have been made to do just that with mixed results."

barry1487 at 17:24 PM on 21 March 2016

Global Warming Basics: What Has Changed?

billev,

You are quite right that the long-term record has intermittent temp rises over multidecadal time scales, with a mid-century period relatively flat.

First thing to note is that the overall trend is upwards.

Second thing to note is that all sorts of factors affect surface temperatures and their evolution, and over different time scales.

Third thing to note is that CO2 warming effect was less in the early part of the 20th century than the latter. Often this is used to argue that CO2 increase can't be the cause, or the primary cause.

Early 20th century warming has been attributed to combination of strong solar and weak CO2 (volcanism plays a part, too). Let's plot solar and temps together. I had to match phase in solar cycle - peak to peak in this case, which forces me to start in 1907 and finish in 1946. Plotting a trend with solar beginning and ending in different phases would give spurious results.

Solar / Surface temps 1907 - 1946

There is some contribution from solar (but solar effect is meant to be quite minimal). There is also a warming from volcanism. 3 factors (at least) contributed to warming in this period (sorry, volcano data is not available at the website I'm using)

How about solar vs recent warming?

Again, I had to make sure phases were matched in the solar cycle, so the post-1974 warming trend has to begin in 1982 and finish in December 2014. I also want to use at least 30-year periods to avoid short-term natural phases (like el Ninos) skewing the results. Note that I have excluded the warm years and months of 2015/16. Though I was forced to in order to match solar cycle phasing, I'm actually glad because I prefer conservative results.

Solar / Surface temps 1982 - 2014

This time, solar is a negative contributon. (Volcanism has been fairly steady for this period)

Now let's compare rates of warming for the first period you indicate, and then the recent period from 1975.

1911 - 1945 rate of warming is 0.138C/decade (+/- 0.045 uncertainty)

1975 - 2015 rate of warming is 0.175C/decade (+/-0.033 uncertainty)

Both trends are statistically signficant (trends since 2002 are not). The more recent mean trend is higher than the earlier one, BUT... the uncertainties overlap, so we can't honestly say that these trends are statistically distinguishable. We can't say that the recent warming rate is faster, slower or the same as 1911-1945. However, this is only one of many statistical tests we could run.

By the same token, we can't claim that the similarity relative periods 'disprove' CO2 contribution. We need attribution studies for that - the graphs above are just a beginning.

One thing that we can definitely not claim is that the future evolution of temp trends will match the previous. We are kind of designed to see patterns whether or not they are actual. If one wants to claim that there is some kind of cycle in climate evolution, one has to deterine a physical mechanism. Attempts have been made to do just that with mixed results.

Whatever natural multidecadal cycles may be present in the long-term evolution of climate, they are not sufficient to explain the long-term (centennial) trend. There are longer temperature cycles (ie the ice ages) but these are at a much slower pace than current.

This is not so much as to finalise an answer, but to get you thinking. If this stuff is well-known to you, hopefully you'll forgive an unnecessary post.

Moderator Response:

[RH] Reduced image size to 500px wide to prevent breaking page format.

tinablake at 17:24 PM on 21 March 2016

After 116 days, MIT fossil fuel divestment sit-in ends in student-administration deal for climate action

Well its longest week for the activities of Fosil free MIT the Vice President and towards all along the research team involvement. Well we have a great opportunity for the entire blogger website because we have a easy website builder for you that is a systematically done by expert developers.

Tom Curtis at 16:23 PM on 21 March 2016

Heat from the Earth’s interior does not control climate

bozza @52 &53, of course the figures are approximate, in the sense that they have error margins. The figure for geothermal flux is plus or minus 4.3%, for example. Given that, it is quite possible although very improbable that it would change by plus or minus 4% from year to year - an amount so small as to be inconsequential to climate change. Errors on radiative forcing of greenhouse gases are typically in the plus or minus 10% range.

With regard to human produced energy, total human energy production by fossil fuel burning and nuclear power stations was 143 x 10^12 Watts as of 2005. Obviously it has increased since then. Your 10 TW value is therefore approximately 7% of the actual value. However, I am not sure I have properly understood what you were saying.

Tom Curtis at 16:01 PM on 21 March 2016

Global Warming Basics: What Has Changed?

billev @6, you can only "only have an observation" if you make no projection. You, however, make projections out to 2099 unconditionally, and to 2350 conditionally. Ergo, you have a theory about the observations, which in fact happens to be false. It does not fit the observations even over the period 1880-2015 unless your terminology is so loose as to make your claims void of meaning, as shown above.

bozzza at 16:00 PM on 21 March 2016

Heat from the Earth’s interior does not control climate

I was of course referring to this figure, "..Earth’s 47 TW interior heat..", quoted in comment 50!

bozzza at 15:58 PM on 21 March 2016

Heat from the Earth’s interior does not control climate

..I was of the long held opinion that humanity used about 10 TW of man-made energy: could it be possible that these figures actually be anywhere near approximate from a rational pov?

chriskoz at 15:17 PM on 21 March 2016

2016 SkS Weekly Digest #12

Today's toon is hardly pro climate science education (or I don't see it that way): it rather reaffirms the n#1 denier's myth on the top left: Climate's changed before.

billev at 15:07 PM on 21 March 2016

Global Warming Basics: What Has Changed?

I don't have a theory. I only have an observation. That observation, based on observing the NOAA furnished temperature history chart, is that the warming experienced since 1880 has not been continuous. I am not talking trends I am talking temperature history. I also believe that the significant imbalance between the scale of the presentation of the years on the horizontal axis versus the temperature anomalies on the vertical axis diminish the ability to read the charts accurately. One thing I have noticed in various comments on the charts is a desperate attempt to mask the probable beginning of another pause in continuous warming that began (in my opinion) in 2002 or 2003. I think that those observing the temperature charts over the next 10 to 15 years will probably see that a pause in warming has occurred.

Tom Curtis at 14:19 PM on 21 March 2016

Heat from the Earth’s interior does not control climate

pjcarson2015 @50, you claim the rate of release of geothermal energy varies significantly due to earthquakes and volcanism, but provide no numbers. Numbers, however, are easy to find. For example, the largest geologically recent eruption is that of Lake Toba in Indonesia, 74 thousand years ago. Here is a comparison of ejected lava for Lake Toba compared to other geologically recent volcanoes:

The Lake Toba erruption was so large that its global impacts may nearly have caused the extinction of the human race. It errupted with a force of 3.3 x 10^18 Joules, equivalent to 9.15 on the Richter scale. Despite that, globally and annually averaged, it represents a forcing of just 0.0002 W/m^2. That is only a 0.2% increase in background geothermal flux, or 0.005% of the forcing from a doubling of CO2.

Of course, for a change in geothermal flux to significantly effect climate, a 0.2% change for just one year isn't going to do it. Rather, you would need significantly more than that increase year in and year out over the long term. So your theory is, not that one Lake Toba erruption equivalent has occurred, but that multiple such eruptions are occuring year in and year out, and we are simply not noticing.

Alternatively you might consider the flux to come from increased earthquake activity, and that we are experiencing significantly greater than twenty times the normal rate of magnitude 9+ earthquakes year in, year out without noticing.

Of course, magnitude 9 earthquakes are fairly noticable, so you may prefer a increase in a lower magnitude quake. But it takes 52,400 magnitude 6 earthquakes to release the same amount of energy as a Lake Toba erruption (magnitude 9.15 equivalent). So for a 0.2% increase in the background rate, you have to imagine that the rate of magnitude 6 earthquakes has increased, year in, year out, by 52,400 per annum over their normal background rate. Unfortunately, the background rate of magnitude 6 earthquakes measured over the twentieth century is 100 to 150 per year. Ergo your theory requires the rate to have risen to that level from a prior rate of -52,275 magnitude 6 earthquakes a year.

Quite frankly, all these alternative proposals are ridiculous.

And what is even more riduculous given that for the change in geothermal flux to be significant relative to the change in heatflow due to the enhanced greenhouse effect, you need a change in the background flux, not of 0.02% but of 10,000%. Again, we would have noticed. Indeed, the measurements which determined the current background rate would have picked it up. The greatest increase in background rate of geothermal flux you can concievably argue for is the current rate of flux of 0.09 W/m^2. And that is insignificant compared to the change due to the change in greenhouse gases, and relies on the unphysical assumption that there was no geothermal flux prior to about 1850.

In short, that you provide no numbers in support of your contention is no accident. That is because if you look at the numbers, you see immediately that your theory cannot be true.

pjcarson2015 at 10:23 AM on 21 March 2016

Heat from the Earth’s interior does not control climate

Planet Earth does its own (analog) calculations which it always gets right. It doesn’t have error bars. (Man is playing catch up in the calculation stakes.) Earth’s input and output energy always balance to zero when the Earth’s temperature is at equilibrium. As I wrote previously, this is the circumstance when Earth’s 47 TW interior heat comes into significance.

As you say, the rate of Earth’s heat production is a very slowly changing property – too slow to be of any significance in these discussions – but its rate of release does vary significantly, principally with earthquakes and volcanism, both of which known to change.

Moderator Response:

[PS] Please note the Comments Policy statement on "No sloganeering". If you wish to make assertions about "Planet Earth does its own calculations", or that geothermal rate can change in a way that could be significant to climate, then you must back your assertions with data and/or papers. You beliefs fly in the face of known data and laws of physics. Please provide the basis for such beliefs.

Tom Curtis at 06:53 AM on 21 March 2016

Tracking the 2°C Limit - February 2016

Rob Honeycutt @16, thanks for the headsup.

Mann's tweet says:

"Feb GISTEMP +1.35C 1951-80 baseline is ~2C relative to true pre-industrial baseline"

Citing the GISTEMP global anomally as he does, that should indicate that he is talking about global temperatures, but it turns out he is not.

Specifically, when you follow up to the referenced article in the Huffington Post, he makes use of information cited in two other articles, one peer reviewed, and one from Scientific American, both of which deal exclusively with Northern Hemisphere temperatures. Indeed, he is quite clear about that in the Huffington Post article.

In the end, the data he shows is used in this graph from the Scientific American article:

This is derived from a combination of temperature data, including BEST NH land back to 1750, forcing data and an energy balance model. Exactly how these are combined to produce the preindustrial temperature is unclear to me. He does provide Matlab code, but as I do not have Matlab, I am unable to read the code. He writes (Huffington Post):

"There are a number of things to note from Fig. 3. First of all, using the more appropriate 1750-1850 pre-industrial baseline, we see that the Northern Hemisphere average temperature (gray squiggly curve) has already warmed nearly 1.2C. Temperatures have exceeded 1C above pre-industrial levels for most of the past decade. So 2015 obviously won’t be the first time this has happened, despite press reports to the contrary."

The 1.2 C figure for the NH is significantly less than the 2001-2011 mean for BEST NH land relative to a 1750-1779 baseline, which is 1.67 C. That is no surprise as a land only anomaly will be higher than an ocean/land anomaly. The difference shows, however, that Mann has not simply taken the BEST land only value, although he may have taken the straight 1750 value, which was high relative to the 1750-1779 mean. I suspect, however, he has used a much better method than that and would not dispute his figure.

What I do dispute is taking the NH as an analogue for the globe. There are good reasons for doing so in the cited articles, specifically the much better historical and paleo records for the NH. But the 2 C target is for global temperatures. Because the NH is approximatley 2/3rds land, it is expected to have a higher anomally than the whole globe at 2 C, and thus 2 C NH is not equivalent to 2 C globally. Suggesting that the February 2016 temperature gives us an idea of what 2 C is like is misleading. We still have significant warming to go before we crack 2 C globally, and thus actually reach the 2 C limit.

Tom Curtis at 05:49 AM on 21 March 2016

Heat from the Earth’s interior does not control climate

pjcarson2015 @48, had you read the original paper from which that diagram it taken, you would notice that the error margins in the absolute values of the "two large quantities" was so large as to not narrow down the difference at all (and would have indicated a much larger difference taken at face value). Consequently the authors used reanalysis products to narrow down difference in the values. More recently, the principle of conservation of energy has been used in conjunction with the much better known increase in surface heat content (mostly in the form of Ocean Heat Content) to constrain the difference between the values.

More importantly, the 47 TerraWatts is a product of radioactive decay and tidal stresses. The tidal energy is also the product of tidal stresses. Absent a major change in the relative orbits of the Earth, Moon and Sun (which has not occurred at any time over the last 4.5 billion years), and/or radical change over time of the fundamental physical constants, these cannot increase over the long term. Indeed, both will gradually decrease over the long term as the amount of radioactive material decreases, and as the Moon gradually moves further from the Earth (reducing tidal stress). In the geologically short term, tidal stresses will change at a rate proportional to continental drift as different configurations of continents induce more or less tidal friction. At the moment the northward migragion of Africa, India, Australia and South America are (very gradually) reducing tidal stress, not increasing it, and the slowness of the process will not result in changes detectable on a centenial scale. In like manner, there has been no new formation of large ignious provinces, or rapid acceleration of continental drift that would be necessary to increase heat flow from the interior (but not heat generation in the interior that necessarilly decreases).

In short, theories that the rapid recent rise in temperatures is primarilly due to factors other than the increase in greenhouse gases suffer the same impediment as another famous 'theory':

Tom Curtis at 05:35 AM on 21 March 2016

GWPF throws out centuries of physics, climate scientists laugh, conservative media fawns

I have responded to richpender on the moderator suggested thread. I'll note here that the very existence of that thread, not to mention papers like this one, and the host of papers on the water vapour feedback effect falsify richpender's claim that "All the attention is given to CO2". It may well be true that he "...see[s] no discussion of [the effect of water vapour] on global warming", but that is not because it is not copiously discussed by the scientific community.

Tom Curtis at 05:27 AM on 21 March 2016

Water vapor is the most powerful greenhouse gas

richpender elsewhere suggests that there is 80 times by volume more H2O and CO2 in the atmosphere.

According to Trenberth and Smith (2005) the total dry mass of the atmosphere is 5.1352 +/-0.0003 x 10^18 kg, while the mean mass of H2O in the atmosphere is 1.27 x 10^16 kg. According to the CDIAC FAQ on Climate Change, each ppmv of CO2 in the atmosphere has a mass of 2.13 Gigatonnes. The most recent IPCC report (AR5) has corrected that to a value of 2.12 Gigatonnes, or 2.12 x 10^12 Kgs. That means with 400 ppmv of CO2, there are approximately 848 x 10^12 Kgs CO2 in the atmosphere. In other words, by mass, there is approximately 1.5 times as much H2O in the atmosphere as there is water. CO2 is heavier than H2O, however.

To run the comparison of the ratio by volume, however, we need to convert from Mass to molar units. Apparently water vapour has a molar mass of 18.02 Kg per kilomole, while CO2 has a molar mass of 44.01 Kg per kilomole. It follows that there are 705.8 x 10^15 moles of H2O in the atmosphere; but only 19.3 x 10^15 moles of CO2 at 400 ppmv. The ratio of H2O to CO2 by volume is therefore 36.6, just under half of richpender's estimate.

I am not sure why richpender got the estimate wrong. Taking a median value on surface humidity, the ratio is approximately 53 moles of H2O per mole of CO2 - a value which does not include clouds (unlike Trenberth's figure). Perhaps richpender has used an area weighted mean of humidity, which would give a larger ration at the surface. Crucially to the strength of the greenhouse effect, what such comparisons nearly always get wrong is using only surface values. Because the volume of H2O in the atmosphere is closely tied to temperature, the H2O concentration falls rapidly with altitude, as seen in this graph by Science of Doom:

(Note that the graph only shows about 320 ppmv for CO2, not the current 400 ppmv).

Because of the rapid decline of H2O concentration with altitude, in the upper troposphere where the greenhouse effect has its major impact, CO2 has a far greater impact than would be expected from surface calculations alone. Indeed, CO2 contributes 20% of the total greenhouse effect, compared to 50% by water vapour and 25% by clouds. The ratio of the instantanous impact of water vapour (plus clouds) to CO2 for the total greenhouse effect is not 80 to 1, not 36.6 to 1, but 3.75 to 1.

That is the instantanious impact only. Because the concentration of H2O in the atmosphere is highly temperature dependent, if the CO2 were eliminated from the atmosphere, the amount of H2O in the atmosphere would fall drastically due to the reduced temperature. That in turn would lead to a further reduction in atmospheric H2O, and a further fall in temperature. The end of the process would leave very little H2O in the atmosphere, and a total greenhouse effect a very small fraction of current values.

Conversely, increasing CO2 increases the amount of H2O in the atmosphere, amplifying the impact of that increase in CO2. This is called the water vapour feedback.

John Hartz at 03:22 AM on 21 March 2016

Sanders, Clinton, Rubio, and Kasich answer climate debate questions

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