Climate indices to watch

What is the most important climate condition to keep tabs on? We have recently mentioned the record-low Arctic sea-ice extent, but hurricanes this year seem to be getting the most attention because of timing ofHurricane Isaac (I know of no evidence suggesting that the Arctic sea-ice has such a direct impact on U.S. politics!).

In addition, the status of ENSO issued by NOAA on August 27, 2012, states that El Niño conditions are likely to develop during August or September 2012, although the present state is classified as ‘ENSO-neutral‘. El Niño has a strong influence on local economies and societies in fairly extensive regions of the world. ENSO is a natural phenomenon, but may change under a changing climate and is interesting to watch over the long term.

It’s important to avoid getting lost into single indicators, however, as the climate system is complex, with many different parts interacting with one another. The American Meteorological Society (AMS) recently put out a statement on climate change, referring to a wide range of different climate indicators (here is a link for the most common ones). The AMS is not alone – the National Academy for Sciences (NAS) is also concerned about our climate and its many aspects: A fairly recent movie called Climate change at the NAS Climate Change: Lines of Evidence provides a comprehensive overview.

Both AMS and NAS accounts provide a rich picture of many different aspects with many different (important) details, which make them fairly long and complicated. This is why simple indices sometimes are used – to convey a simple message. We need both, and that’s why the NAS video and the AMS statement are so valuable – at least for the readers who understand what they are talking about. I’m not sure that everybody does, though.

R-script for making pretty picture

109 comments on this post.
  1. MMM:

    I would recommend the EPA climate indicators as another resource:

  2. Alexandre:

    When I see the Mauna Loa graph I can’t help becoming puzzled by claims of “panic” or “overreaction” about global warming. Really, I can’t see any reaction whatsoever.

  3. NeilT:

    Linking the 800k historical animation would also be good. It is excellent and really shows the whole true picture of CO2 in the interglacials, Glacials and now.

  4. Lance Olsen:

    We also have many important indicators in the planet’s biological systems. Fisheries, forests, and grasslands, for example, are all telling us how the new climate is advancing. For a broad overview of aquatic, marine, and terrestrial change found among systems (and species) I think it’s hard to do better than to start with the 800+ papers reviewed in Parmesan, Camille. “Ecological and Evolutionary Responses to Recent Climate Change.” Annual Review of Ecology, Evolution, and Systematics. 2006. 37: 637-69

  5. Tom Fiddaman:

    Evidently my brief comment that the graphic was chartjunk didn’t make the moderation cut – I will try to clarify.

    The point is not that there’s anything wrong with this post, but that it’s tough to be good communicators of science without adhering to some standards of presentation. We need to raise the level of debate, because we can’t win with pretty pictures. A chart with a nonzero y-axis baseline and no units of measure is only convincing for the time it takes to get from here to WattsUpWithThat.

    [Response:Pretty pictures like this make it into the media – the traditional ones usually don’t – at least in my experience. It is of enormous help if we can use graphs together with words in the press. There is no contradiction in combining pretty pictures with solid science, and I think solid science can be made much more interesting with pretty pictures. However, we need to break with prejudice about ‘how science should look’ (prejucide is not science). Science is not about bein pompous either (traditinally looking figures), but I include R-scripts for all my pictures (science should be replicable and transparent), and all the graphs are based on quality data from well-known institutions (URLs for the sources are in the R-scripts). I save the ‘sciency looking’ graphs for the science literature and for when I use them to explain a point – here the role of the pretty picture was to illustrate the most icnoic climate index that I know of. -rasmus]

  6. MARodger:

    Call me ‘alarmist’ but I don’t think the 800k really captures the true significance of CO2 curve. Using ocean sediments, it has been show that 300ppm had hardily been exceeded over the last 2.1 million years. So 400ppm (recorded up in the Arctic this year & now no more than two summer away at MLO) is something not seen in what, 15 million years? And all achieved within a century.
    15M:100. That’s some ratio!!

  7. richard pauli:

    Great question to pose. There are classic indicators – CO2, aerosols and temperatures of air, ocean and cryo – all important.

    I hope we keep an eye on methane levels, and ocean ph.

    Then there are consequences of continued carbon combustion like tropospheric O3 levels, — it is a ghg and weakens most all life forms. O3 levels now regularly spike in high combustion areas.

  8. David Donovan:

    It would be nice to have some numbers on the y-axis of the title figure.

  9. Leif:

    Given that the whole denier-sphere is funded by the fundamental flaw of Western Capitalism that allows, nay, encourages the few to profit from the pollution and exploitation of the commons for personal gains, I would think that the most important metric to watch is when the ~77% currently in favor climate disruption mitigation is to become a majority action in a presumably democratic Nation.

    We all pay fees to dump garbage, waste water and more. Corpro/People dump tons for free and accumulate mega-bucks. Even get tax subsidies. The GOP don’t fund abortion. Fine. A precedent! Why must my tax dollars fund the ecocide of the PLANET via fossil subsidies?!!! We’re talking “MORALS” here. Try throwing 19 pounds of paper cups out the car window for each gallon of gas you burn. Who is making money here and who is losing? Toxins verses paper cups? (I bet you could be real creative about increasing your trash stream if it were paper cups.) Even absorb a “slap on the wrist” fine once in awhile. Surely a good lawyer on retainer. Once established perhaps even a congressman or two.

    I pay $150/ton to dump my household garbage. $50/T to recycle yard waste. Waste water fees, of course. I even have a rain water run of fee of $5/m. (guide lines here?) Yet Corpro/people piss all over themselves at the thought of $25/ton for TOXINS! Sweet Jesus… They are making billions, I get ~$30/day to stay alive and must fund health insurance. Go Figure!

    In brief:

    Stop profits from the pollution of the commons.
    Go Green, Resistance is FATAL to Earth’s life support systems.

  10. Jeffrey Davis:

    re: 3

    I don’t know why that’s labeled 800,000 years ago. It’s from 1979.

  11. Didactylos:

    Tom Fiddaman: I believe the term is “infographic”.

    It’s sad that people always truck out the same complaints about zero points and units, because it shows a lack of understanding about context. Sometimes the zero point can be left off in order to deceive, and units can be misused. Here, however, we have a situation where the signal to noise ratio is very, very high, and the increase is significant without recourse to nitpicks over units or zero points. In short, it is an image which can be understood without any great scientific knowledge, while also not distorting the science in any way.

    Yes, the chart could contain more science. It could indicate that CO2 levels have nearly doubled. It could include the fascinating fact that CO2 is measured in parts per million (by volume). And so on, and so on…. but these distract from the key message of the chart.

  12. dbostrom:

    Abyssal warming? Little remarked, sparse data, small in absolute numbers but statistically significant and widespread.

  13. Patrick:

    Thank you. The linked resources are very helpful–lots of good stuff. But I always worry when I hear “geo-engineering” mentioned, even with caution. The best geo-engineering I know is called photovoltaics and wind energy systems.
    Here’s some right here:

    Near-zero emissions. Negligible waste heat. All the weirdness you want–right here in the prevention phase–no need to run to weird remedial schemes.

    I can’t wait for someone calculate and model–emissions aside–the total btu’s of waste heat contributed globally by all power plants and combustion engines. Or the btu’s of waste heat per person from same.

  14. Tom Fiddaman:

    @didactylos – The signal to noise ratio on CO2 measurements is extremely high. The signal to noise ratio in the climate debate is extremely low. Cherry-picked timelines and arbitrary baselines are rampant among the septic crowd. “Infographics” legitimate those practices. Why do it, without a compelling purpose?

  15. NeilT:

    @6 MARodger

    Actually I’ve found it more constructive if you scare people just enough. Scaring them to death is counterproductive as most of them just go into total denial mode and don’t come out for a few years until they have got used to the idea.

    I work extensively with change management in my day job as I, basically, ruin you day when I run my migration projects. We work a lot with the Kübler-Ross model.

    I found that the 800k animation was a great tool in getting people who were still in denial to get out of it and recognise that we are driving this change. We don’t need to use millions or total disaster or anything else.

    We’re not actually asking for total and complete transformation of people’s lives. Just to cut it down a bit and keep on going like that until we can try to balance the situation.

    Small actions require compelling evidence but not complete disaster movies.

  16. Patrick:

    @5: I don’t think it’s chartjunk at all. It’s a stlye-graphic which servesas a headline. This post is high-q info, with lots more linked in–which is hardly the case at the the postjunk site you mention.

    I like climate science communication, not disinformation.

  17. Radge Havers:

    This may be a naive, even lazy, question. I seem to have missed the answer. Is some sort of a composite index feasible?

  18. Aaron Lewis:

    The bottom line is always: FOOD; has the weather damaged the crops? Will the weather damage the crops next year? How many corn crops will have to fail before we admit that it is getting too hot for corn?

    As a society,we need to ask ourselves, When do we admit that for practical purposes, “Global warming is here”?

    However, I think we have to go back and look at food production after CO2 rose above 350 ppmv to see changes in the system.


  19. Hank Roberts:

    This presentation has several excellent illustrations:

  20. Didactylos:

    Tom Fiddaman, before you throw around terms like “chartjunk”, you need to have an understanding of the data. In this instance, a very famous, well known dataset is reproduced. The source of the data is given, and all the data is included. It is not cropped or tampered with in any way. The form the data is presented in is entirely appropriate, showing the long term trend and the seasonal signal. Moreover, it is how this dataset is usually portrayed.

    The vertical axis is not easy for everyone to understand, and its omission only offends those who already know what it is and what it means (and are capable of finding the original data)…. so who exactly is outraged here?

    Infographics are important, and we should be looking for ways to make them clearer and more correct, not throwing up our hands in horror and completely abdicating any responsibility to communicate to people who do not speak the language of climate science.

    One of the cardinal sins of scientists is including too much information in a single chart or diagram. For the lay public, clarity and simplicity are vital.

  21. MARodger:

    Jeffrey Davis @10
    The link @3 starts off from 1979 which is presumably where there are enough CO2 records to provide the wobbly line showing CO2 at different latitudes. When it reaches 2011 (despite being titled 2009)it then starts backwards from 1979 and its title then becomes clear.

  22. MMM:

    “nonzero y-axis baseline”

    Yes. Which is why when the newspaper shows temperatures from the last 5 days, I complain because they didn’t start at zero kelvin. Or why when I get a topographic summary of my hiking route I complain because they don’t show the graph starting at sea level.

    As with all charts and graphics, the appropriate choice depends on the information being conveyed. A zero baseline may be appropriate in many circumstances, but not in all (and can depend on the choice of unit: a zero Celsius baseline is different from a zero Fahrenheit baseline is different from a zero Kelvin baseline).

  23. tamino:

    And if you labeled your axes i could tell you by exactly how much

  24. M Tucker:

    MARodger @ 6

    The earth was at around 400ppm about 3 million years ago during the Pliocene warm period. That time period has been extensively studied beginning with the work of Soviet climatologist Mikhail Budyko and then taken up by the USGS in the 1980’s. It continues today as the USGS PRISM project (Pliocene Research Interpretation and Synoptic Mapping.) The work is used to understand what the world is in for in geologically short order and it is used to help verify climate models.

  25. Jim Larsen:

    13 Patrick said, “I can’t wait for someone calculate and model–emissions aside–the total btu’s of waste heat contributed globally by all power plants and combustion engines. ”

    Been done. I don’t have a link, but the result is that waste heat is totally negligible.

  26. owl905:

    Top indicies to watch –
    GHG pollution levels. They drive the disruption.
    Extreme Events. The consequences are in there. The costs are gigantic.
    Global temperatures.
    Sea levels.
    Extinctions and migrations.
    Food supplies.

    Things not to watch –
    Anything from Watt, McIntyre, Goddard, Moncton, Lomborg, et. al.;
    Youtube’s that disprove AGW;
    Antarctic sea-ice;
    Sunspots (literally, and for incite on AGW).

  27. David B. Benson:

    Radge Havers @17 — A composite index is possible of course. Its usefulness remains most uncertain.

  28. sidd:

    These are not strictly climate indices, but …

    1)GRACE mass waste for WAIS and GRIS
    2)Velocity maps for Jacobshawn,Peterman,Zacharie Isstrom/Nioghalvfjerdsforden,Thwaites,PIG


  29. dbostrom:

    Jim: [waste heat] Been done. I don’t have a link, but the result is that waste heat is totally negligible.

    0.028w/m2 vs. 2.9w/m2

    See this amusing coverage at Skeptical Science:

    It’s waste heat


    Waste heat versus greenhouse warming

    A breathtaking metaphor; hundreds of particles of enlightenment jostling against jiggly nuggets of what might be termed “dark matter,” apparently accomplishing no useful work. The last iota of energy was apparently dissipated back in February of this year, after a run of some several years. Cold now, no doubt still very dark in places.

  30. Russell:

    Don’t forget the oldest economic climate index of them all

  31. michael sweet:

    Denial Depot had this excellent post on why you need to include zero as part of the y axis to analyze ice records. They also show the time of analysis as the entire history of the Earth going back all the way to creation in 6,000 BC.

  32. Patrick:

    Thanks d-bo @29 et al.

  33. Tom Fiddaman:

    @20 My objection has nothing to do with the data portrayed, which I understand perfectly well. I also agree that “Infographics are important, and we should be looking for ways to make them clearer and more correct…”

    But I don’t see how this reaches anyone for whom “The vertical axis is not easy … to understand.” For them, this conveys, “ooh … wiggly line going up on a dirty refinery.” But the nutjobs have just as many wiggly lines doing other things with which to distract the naive.

    I could suggest some improvements to the graphic, but I think it’s a distraction from the main point of this post, so I’ll refrain from further comment, and hope for things to be a bit more metric in the future, in the spirit of @23.

  34. John Mashey:

    We’ve been seeing lots of graphs lately.
    People might find Solomon Hsiang’s ideas interesting, worth encouraging. There has been discussion at Andrew Gelman’s, here or earlier.

    The fundamental issue is exploring better ways to show uncertainty. I’ve long disliked the usual CI bars (with horizontal endpoints). Solomon’s (and Felix’s) later attempts seem to be going in the right direction. People interested in visual displays of statistical information might take a look and encourage this.

  35. vukcevic:

    We shouldn’t forget the North Atlantic SST (the AMO) which is often ignored. Since 2000 the short term oscillations appear to be suppressed , this could be an indication of ‘energy saturation’ and that multidecadal peak has been reached, implying significant cooling in the coming decades.
    300 years of the AMO from Mann, Gray etc.

    [Response: As the person who coined the term “AMO” I figure it’s appropriate for me to comment. The AMO, as we have shown in numerous articles, has little influence on global (or even Northern Hemisphere) average temperature. Its largely a zero sum game because it mostly associated with changes in the transport of heat between regions, and not the total heat budget of the planet. I talk about the history of the AMO (and my role in it) in my book The Hockey Stick and the Climate Wars -mike]

  36. MARodger:

    M Tucker @24
    Thank you for the comment. It is good to revise bold assertions periodically. So, how long was 400ppm last seen on the planet? I have been saying 15 million years (with varying levels of caveat) based on graphs like this which is a bold statement although beyond the 0.8M ice core data & 2.1M ocean ooze data the uncertainty is probably the biggest factor.
    So “around 400ppm about 3 million years ago” also appears a bold statement.

    The 400ppm number does indeed start appearing from a ‘Pliocene CO2’ search (& even more with a ‘RISM CO2’ search). But there is a “but” attached to that.
    For instance, there is Wikipedia but the citations date back to 1996 which is getting a bit long in the tooth. There is the number 405ppm that appears occasionally but that appears to have dropped out of a model not proxy evidence. And there are more general quotes comparing Pliocene CO2 levels to 21st century levels or slightly higher than today but these are quotes which feels wrong – if Pliocene CO2 is now considered 400+ppm (while modern graphical reconstructions of paleoCO2 do not), why do I not find papers with the 400ppm finding (instead of just finding effectively what are newspaper reporting it).
    And why do I find a 2009 paper saying (okay with a 1996 reference but this isn’t Wiki) “Estimates of atmospheric CO2 concentrations, however, show values only slightly higher than preindustrial concentrations (Raymo et al., 1996),” or Jiang et al 2005 seemingly showing the value of 315ppm (but paywalled).

    My conclusion from all this is that the 400ppm 3Mybp is but surmised from the argument that the glaciation in following years appears to be due to a forcing perhaps caused by drop in CO2 rather than the appearance of the Panama isthmus or some other event, something proposed here by Lunt et al.

    Now I am ever conscious of my caveats (which were reduced to a “?” @6 above), I am happy to revise my timescales in light of any findings unknown to me.
    So if there are such, do not keep them secret. If there are not, do follow my lead & provide caveats with your 3Mybp assertion.

  37. David B. Benson:

    MARodger @36 — Well done.

  38. AlaskaHoundish:

    C02 at the3 1000hPa, 800hPa, 500hPa, 200hPa right up to 10hPa are relevant. Mixing of all atmospheric constituents at all levels are relevant.
    The concentrations, their interactions are unknown, especially in regard to changes with PDO, AO, NAO, Indian Dipole and the Antarctic stream. When we understand the atmospheric physics involved with stratwarm, 6 hours delays in the gravity waves, etc… we’ll know what is needed to swing from inter-glacial to glacial conditions and visaversa.
    Right now C02 has a lifetime expectancy, but so do the mixes we measure at different heights. We certainly do not know what the ever-changing variables in atmospheric chemistry are telling us.

  39. Susan Anderson:

    John Mashey, those are gorgeous!

  40. Walt Rainboth:

    I just ran across a strange new paper that has been accepted by Global and Planetary Change which seems to be interpreting temperature change as leading CO2 change, and that changes in atmospheric CO2 are not tracking changes in human emissions. It was just released through Science Direct. I don’t have the paper yet but those graphs look pretty strange even though they are too small to read any specifics on. The graph of CO2 looks like a Keeling curve that is flattened to produce no overall increase. I have asked our library to get a copy for me, but thought I’d give you a heads up.

    [Response: The paper (Humlum et al) is indeed an odd one. Basically they have made the same mistake as Mclean et al (2009) and assumed that the correlations in growth rate of CO2 and T tell you something about the long term trends (it doesn’t – it tells you only about the fluctuations around the trend). Basically they have rediscovered that ENSO affects the carbonc cycle. Since they are repeating a previous error, their paper also comes pre-rebutted by the response to McClean by Foster et al (2010). – gavin]

  41. Ben Hocking:

    A nice simple graph that I thought conveyed the point simply is the one here:
    (I think I’ve seen that same graph elsewhere, so I’m pretty sure it’s not original with them.) I like it because it conveys two things:
    1) That on a decadal level, the change has been steady since we’ve started taking measurements, despite what that silly Energy Tribune article says. (I won’t link to it, but if you don’t know what I’m talking about, it’s titled ‘Arctic Sea Ice Record Low Is “Broken”’.)
    2) The rate of melt appears to be accelerating. (However, I make the stunning prediction that acceleration will come to a sudden halt when we hit zero.)
    I’d love to see that graph reproduced with 2010-2012 used as a stand-in for the 2010’s average, although I realize that with only 2 or 3 years (depending on time of year) it’s bound to be far noisier.

    Also, add me to the list of people who’d love to see zero included on all of these graphs of melting sea ice area, extent, and volume. Sure, there are reasons not to always include zero on graphs (cf. the witty comment about Kelvin), but given that we’re rapidly heading to zero, for these graphs including it only makes the case stronger, in my opinion.

  42. Jeffrey Davis:

    re: 21

    Ah thanks. Much more polite than a 2×4 across the bridge of the nose.

  43. Edward Greisch:

    Another index: Rivers running dry:,0,6051251.story

  44. ozajh:

    Aaron Lewis @ 15,

    I agree with your comment about food, but the problem is that throughout the so-called First World the overall AVAILABILITY of food is taken absolutely for granted.

    People bitch about price, sure, myself included; but when the increase in grain prices mean that it takes 10 minutes instead of 5 minutes to earn the cost of a good loaf of bread, then it really isn’t a big deal.

    Even when we see pictures of famines elsewhere it doesn’t register viscerally that that could be US after a few years of crop failure . . .

  45. Edward Greisch:

    13 Patrick: Waste heat is irrelevant. We are dumping heat into deep space, and the universe has a temperature of 2.7 degrees Kelvin. The temperature of the universe keeps going down because the universe is expanding and will continue to expand for ever. So forget about waste heat. The CO2 ppm controls the temperature of the Earth.

    PS: Photovoltaics and wind energy systems require industrial processes which make CO2. How much?

  46. Adam H:

    MARodger @36 says
    “And why do I find a 2009 paper saying (okay with a 1996 reference but this isn’t Wiki) “Estimates of atmospheric CO2 concentrations, however, show values only slightly higher than postindustrial concentrations (Raymo etal 1996)”

    Hopefully this isn’t too off topic, but I remember thinking the same thing when I read the 2009 PRISM paper. Raymo etal 1996 is based on an inverse relationship between Carbon-13 and local CO2 concentrations in marine organic matter. I’m no expert on the seas, but I know terrestrial photosynthesis also bears this relationship. However, the isotopic fractionation of terrestrial systems is just as easily influenced by other environmental factors, such as oxygen concentration (see ‘CO2/02 specificity’ in D.W.Lawlor, 2000, Photosynthesis, 400p). Is anyone else skeptical of assuming the isotopic trends in Raymo et al are due to CO2 alone?

  47. Martin Vermeer:

    Actually for CO2 a logarithmic plot would be the way to go, as in physically realistic. And then the zero point is completely arbitrary, a consequence of the unit chosen.

  48. owl905:

    ozajah@44 wrote:- “when the increase in grain prices mean that it takes 10 minutes instead of 5 minutes to earn the cost of a good loaf of bread”

    It means something far greater than that when the failure is wheat and corn and vegetables and livestock. If it’s a 2006-type shock, things can take years to recover (rice) – if it’s multiple shocks in a short time-span it can destabilize regions of the world.

  49. Pete Dunkelberg:

    @ 45:”We are dumping heat into deep space, and the universe has a temperature of 2.7 degrees Kelvin.”

    That would be 2.7 kelvins or 2.7 K, no degrees. That seems to be one of the hardest things in physics. ;)

    If 2.7 K is the right value it’s cooled a little since last I checked (or is it a memory fault?) but since I’m not going there I won’t worry about it.

  50. Chris G:

    On the food thread:

    Aaron @
    posted interesting links, but I’m wondering if there is a bigger picture available. World food prices are the scope I’m looking for, but price is a function of supply and demand, and I’m looking for just supply. Productivity of the US is interesting, but it is just the US.

    I think it would be very interesting if there was a summation of yields per acre planted (for the major grains) over the same time period as Hansen’s climate dice paper. My guess is that there will be a strong, negative correlation between percentage of land area covered by 3-sigma events and yield per acre.

    If so, it might be a clear indication of what we have to look forward to as the occurrence of 3-sigma and greater events increases. (And it would be useful in countering the CO2-is-plant-food meme.)

    In regions where food accounts for less than 5% of annual income, a doubling will impact lives, but not be crippling. Regions where food accounts for higher percentages of income will be impacted more severely, and at some level, less than 50%, a doubling of food prices becomes catastrophic.

    // mumsction clan ?