The difficulty of communicating climate change

I haven’t mentioned RealClimate here for quite some time (old posts are here) but continue to follow its articles and browse the comments pages, because it’s such a great source of informed debate about climate science. This recent exchange amongst the comments on a post about climate “skepticism” caught my eye because Dan Miller’s explanation for the difficulty of communicating the climate crisis is so succinct.

Gordon Shephard said:
… Ernest Becker, winner of the Pulitzer Prize for his book “The Denial of Death,” argues that anxiety about one’s mortality is (for the vast majority of people) the psyche’s strongest motivator. It is not that people don’t believe they are going to die, or that they fear death specifically, but that they hope that, somehow, their symbolic immortality will be assured as long as their particular vision of the future of humanity persists. Tell someone that their particular version is doomed, and they will fight you tooth and nail.
Certainly some individuals have conscious motives for “sowing confusion.” But many will feel (unconsciously) that the possibility of a radical change in the course of humanity’s future (such as that which will result from significant climate change) is a direct threat to their vision of their symbolic immortality. They will grasp the thinnest of straws just to say it isn’t so.

Dan Miller replied:
In addition to the psychological resistance to a vision of a failed future, there are other psychological barriers to facing climate change.
Humans evolved to filter information and focus on near-term dangers, like a lion approaching. There are six triggers that get us to focus on a problem: 1. Immediate, 2. Visible, 3. Historical Precedence, 4. Simple Causality, 5. Direct Personal Consequences, and 6. Caused by an Enemy. Until recently, climate change had 0 of 6 (you could now say that it is somewhat visible). Number 6 is an important one… imagine if we found out tomorrow that all the excess CO2 is being released by North Korea in order to destabilize the climate. We would take care of that swiftly!
It’s almost as if the climate crisis was designed by a diabolical genius specifically so that we will not respond in time. You can see more on this in my TEDx talk.

Demystifying science-speak

Here is a great table of word substitutions for scientists to make when talking to non-scientists, or for non-scientists to mentally make when reading scientific articles. I saw it on Real Climate and, like the person who posted it there, thought that it deserved a wider audience. It comes originally from a lecture by Richard Somerville at UC San Diego on communicating climate science, part of this course.

Terms that have different meanings for scientists and the public

Scientific term  Public meaning  Better choice
enhance improve intensify, increase
aerosol spray can tiny atmospheric particle
positive trend good trend upward trend
positive feedback good response, praise vicious cycle, self-reinforcing cycle
theory hunch, speculation scientific understanding
uncertainty ignorance range
error mistake, wrong, incorrect difference from exact true number
bias distortion, political motive offset from an observation
sign indication, astrological sign plus or minus sign
values ethics, monetary value numbers, quantity
manipulation illicit tampering scientific data processing
scheme devious plot systematic plan
anomaly abnormal occurrence change from long-term average

 

Warning: climate change ahead

climate-crisis-aheadThe really short version of the climate change story hasn’t changed much for the last ten years or more, of course: we know we are cooking the earth and things are going to get very uncomfortable, if not catstrophic, unless we stop pumping CO2 into the atmosphere. (NASA’s version is one of the simplest, clearest and most authoritative if you need to direct anyone to such a resource.) However, the scientific work continues to improve our knowledge every year. Two significant recent publications are discussed in not-too-technical terms in two highly regarded blogs, RealClimate and ThinkProgress.

Should we trust the bloggers? These bloggers, yes. Stefan Rahmstorf, who discusses Marcott’s paper in Science, teaches physics of the oceans as a professor at Potsdam University, is a member of the Advisory Council on Global Change of the German government and is a lead author of the paleoclimate chapter of the 4th assessment report of the IPCC. Joe Romm, who discusses Hansen’s paper, worked at the highest levels of the US Department of Energy in the 1990s before moving into full-time environmental campaigning. (For more about them, see Wikipedia: Rahmstorf, Romm.) From here on, this summary uses their words, drastically condensed; follow the links at the end for the full versions.

Marcott study: The End of the Holocene

by Stefan Rahmstorf

Recently a group of researchers from Harvard and Oregon State University has published the first global temperature reconstruction for the last 11,000 years – that’s the whole Holocene (Marcott et al. 2013). The results are striking.

Over the last decades, numerous researchers have painstakingly collected, analyzed, dated, and calibrated many data series that allow us to reconstruct climate before the age of direct measurements. Such data come e.g. from sediment drilling in the deep sea, from corals, ice cores and other sources. Shaun Marcott and colleagues for the first time assembled 73 such data sets from around the world into a global temperature reconstruction for the Holocene [i.e. the 11,700 years since the last Ice Age].

Marcott s

Global temperature reconstruction from proxy data by Marcott et al, Science 2013

The climate curve looks like a “hump”. At the beginning of the Holocene global temperature increased, and subsequently it decreased again by 0.7 ° C over the past 5000 years. The well-known transition from the relatively warm Medieval into the “little ice age” turns out to be part of a much longer-term cooling, which ended abruptly with the rapid warming of the 20th Century. Within a hundred years, the cooling of the previous 5000 years was undone. (One result of this is, for example, that the famous iceman ‘Ötzi’, who disappeared under ice 5000 years ago, reappeared in 1991.)

Conclusion

The curve of Marcott et al. will not be the last word on the global temperature history during the Holocene; like Mann et al. in 1998 [the famous “Hockey Stick” which was a similar temperature record for the last 1,000 years] it is the opening of the scientific discussion. There will certainly be some corrections and improvements. However, I believe that (as was the case with Mann et al.) the basic shape will prove correct: a relatively smooth curve with slow cooling trend lasting millennia from the Holocene optimum to the “little ice age”, mainly driven by the orbital cycles. At the end this cooling trend is abruptly reversed by the modern anthropogenic warming. …

Just looking at the known drivers [factors affecting climate change] and the actual temperature history shows it directly, without need for a climate model: without the increase in greenhouse gases caused by humans, the slow cooling trend would have continued. Thus virtually the entire warming of the 20th Century is due to man. This May, for the first time in at least a million years, the concentration of carbon dioxide in our atmosphere has exceeded the threshold of 400 ppm. If we do not stop this trend very soon, we will not recognize our Earth by the end of this century.

Hansen study: Climate Sensitivity is High, Burning All Fossil Fuels Would Make Most of Planet ‘Uninhabitable’

by Joe Romm, Sept 17, 2013

James Hansen, the country’s most prescient climatologist, is out with another must-read paper, “Climate sensitivity, sea level and atmospheric carbon dioxide,” … co-authored by a number of Hansen’s former colleagues at NASA. … The key findings are:

• The Earth’s actual sensitivity to a doubling of CO2 levels from preindustrial levels (to 550 ppm) — including slow feedbacks — is likely to be larger than 3–4°C (5.4-7.2°F).
• Given that we are headed towards a tripling (820 ppm) or quadrupling (1100 ppm) of atmospheric CO2 levels, inaction is untenable.
• “Burning all fossil fuels” would warm land areas on average about 20°C (36°F) and warm the poles a stunning 30°C (54°F). This “would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change.”

Burning all or even most fossil fuels would be a true scorched Earth policy.

Given that James Hansen has been right about global warming for more than 3 decades, his climate warnings need to be taken seriously. [The] whole paper is worth reading. The authors conclude:

Most of the remaining fossil fuel carbon is in coal and unconventional oil and gas. Thus, it seems, humanity stands at a fork in the road. As conventional oil and gas are depleted, will we move to carbon-free energy and efficiency—or to unconventional fossil fuels and coal?

If fossil fuels were made to pay their costs to society, costs of pollution and climate change, carbon-free alternatives might supplant fossil fuels over a period of decades. However, if governments force the public to bear the external costs and even subsidize fossil fuels, carbon emissions are likely to continue to grow, with deleterious consequences for young people and future generations.

It seems implausible that humanity will not alter its energy course as consequences of burning all fossil fuels become clearer. Yet strong evidence about the dangers of human-made climate change have so far had little effect. Whether governments continue to be so foolhardy as to allow or encourage development of all fossil fuels may determine the fate of humanity.

That’s the end of my quote from Romm’s blog, and now you know the considered opinion of the experts. But we will be all right here in Oz, of course:

bed-time-story

Sources:

Realclimate post on Marcott: http://www.realclimate.org/index.php/archives/2013/09/paleoclimate-the-end-of-the-holocene/

Marcott’s paper on Science: http://www.sciencemag.org/content/339/6124/1198.abstract
Science 8 March 2013
A Reconstruction of Regional and Global Temperature for the Past 11,300 Years
Shaun A. Marcott1, Jeremy D. Shakun, Peter U. Clark, Alan C. Mix

ThinkProgress post on Hansen: http://thinkprogress.org/climate/2013/09/17/1892241/hansen-climate-sensitivity-uninhabitable/

Defining a rapidly changing climate

If the climate is changing, what is it that’s changing? Climate, they say, is what you expect, while weather is what you get. But if climate is changing, how do we know what to expect?

That may sound flippant but it has become quite a serious question in climate science circles of late, for two reasons: communicating climate science to the public, and dealing with the statistical problem of defining a moving target.

On the first question, for instance, we have a typical member of the public asking on the RealClimate open thread“One thing that has confused me is how long it takes for weather to become climate.”

One of the regulars replied: “WMO (World Meteorological Organization) states that climate is 30 or more years of weather data.” Another backed him up, saying, “The traditional answer is 30 years or thereabouts.” ‘SecularAnimist’, another regular, answered at greater length:

I think this question is increasingly irrelevant, and the “traditional” answer is becoming obsolete.

The question was relevant when we were asking whether the various atmospheric conditions, processes, events and patterns of events that comprise “climate” are in fact changing, and wanted to know over what length of time we’d need to observe those phenomena as ever-changing, short term “weather” to be able to conclude that the changes are sufficiently long-term to be considered “climate” change. But we already know that the climate is changing, and will continue to change, as a result of our CO2 emissions. We don’t need 30 more years of observations to tell us that, now.

And the “traditional” answer is obsolete because it presumes that the Earth’s climate is sufficiently stable, and changing so slowly, that it really does take 30 or more years of observations to detect any long-term, large-scale change. That’s no longer the case, because the climate system is being driven to change more rapidly and extremely than it has ever done in human history. It’s unlikely to take another 30 years for the American midwest to become desert. It’s unlikely to take another 30 years for the Arctic sea ice to disappear completely during summer — with all of the prodigious effects that implies.

There is every reason to expect that permanent, large-scale, dramatic changes, which cannot reasonably be called anything but “climate change”, may now occur on time scales of a few years, rather than a few decades, as would have been expected in the pre-AGW world.

The more technical problem with the definition of climate is that weather needs to be averaged over enough annual cycles to iron out the bumps caused by specific weather events (that’s where the ’30 years’ comes from) but if, for instance, the averages of the 1980s, 1990s, and 2000s are successively quite different from each other then a ‘climate’ defined by the 1980-2010 average becomes meaningless.

Should we just average over a shorter period, then? No, because known multi-year cycles such as El Nino will distort the result too much. As far as I know, the experts are still working out what to do about that. Meanwhile they tend to define our baseline climate by the period from 1951-1980. James Hansen, whom I have mentioned before, presents the reasons very sensibly in a very recent discussion of his recent ‘climate dice’ paper:

Studies of climate change generally use some base period to define an average climate and calculate “anomalies” relative to that average, i.e., climate anomalies are the deviations from that average climate. In our papers we used 1951-1980 as the base period.

Global temperature change over the past century (Fig. 1) helps us discuss possible effects of the choice of base period. Our choice of 1951-1980 as a base period has several merits:

1) The period 1951-1980 is prior to the large warming of the past few decades. If we wish to examine the effect of that global warming on climate, we must compare with the climate that existed prior to that warming.

2) The 1951-1980 period has the best global data coverage and can best characterize climate variability. Spatial coverage of data was poorer at earlier times.

3) 1951-1980 was the base period used by the National Weather Service and other researchers when we made our first analyses of observations and climate simulations. For comparison with these early analyses and climate simulations we should use the same base period.

4) Many of today’s adults, baby-boomers, grew up during 1951-1980, so it is recent enough for many people to remember what the climate was like.

The whole discussion is well worth reading, since it presents the key findings of the longer and more technical paper in a very approachable way. Download it (pdf) from here.

Climate Change – Picturing the Science

Cover of Climate Change – Picturing the ScienceClimate Change – Picturing the Science
Gavin Schmidt and Joshua Wolfe, Norton, 2009

This is the perfect book to give someone who doesn’t know much about climate change but  is interested in knowing more. It is authoritative but non-technical, uncompromising but never shrill or aggressive, and lucid but not simplistic.

Schmidt is a climate scientist at NASA and co-founder of RealClimate, and in the latter role he has patiently explained climate science to all comers from school children to fellow experts, for years. He is very, very good at it and here he has recruited similarly well-qualified people to write on specific topics. Any single chapter can stand alone, making the book simultaneously very browsable and a useful fill-the-gaps reference.

Schmidt’s over-arching metaphor for the book is the health of our planet: Symptoms, Diagnosis and Cure. It’s a good metaphor (the Buddha used it 2500 years ago, so it has a good long track record!) and it lets him organise a complicated mass of material into a coherent story about how we know what’s going on around us, why it’s happening and what’s likely to happen, and how we might avert the worst of the likely consequences.

So far, so much better than most books on the subject, but it gets better still. His co-author is a photographer and the book is copiously illustrated with excellent photos – scientists at work, hurricanes, threatened species, Arctic houses subsiding into thawing permafrost, air pollution in Beijing … all sorts of images, and all relevant and memorable.

Longer reviewsNature and Daily Kos.

Remembering the floods

I wrote about extreme weather events and their connection to global warming two and a half months ago and a small coincidence leads me to revisit the topic. Today has been chosen as the day of remembrance for the disastrous SE Queensland floods a year ago, and a link on RealClimate took me yesterday to a paper by eminent climate scientist James Hansen which touches on something I’ve been thinking about for some  time: the fact that climate change should already be apparent to ordinary people.

First, the floods. Wikipedia has a good overview here with plenty of links to further information and the ABC has put together a terrific gallery of flood photos here. There’s not much point in trying to add to that coverage here. The floods certainly qualify as an ‘extreme weather event’ and were recognised as such in the major global report State of the Climate in 2010 from NOAA and the Bulletin of the American Meteorological Society. 

Hansen’s paper, Climate Variability and Climate Change: The New Climate Dice (November 2011) (pdf here) begins thus:

The “climate dice” describing the chance of an unusually warm or cool season, relative to the climatology of 1951-1980, have progressively become more “loaded” during the past 30 years, coincident with increased global warming. The most dramatic and important change of the climate dice is the appearance of a new category of extreme climate outliers. …

The greatest barrier to public recognition of human-made climate change is the natural variability of climate. How can a person discern long-term climate change, given the notorious variability of local weather and climate from day to day and year to year?

This question assumes great practical importance, because of the need for the public to appreciate the significance of human-made global warming. Actions to stem emissions of the gases that cause global warming, mainly CO2, are unlikely to approach what is needed until the public perceives that human-made climate change is underway and will have disastrous consequences if effective actions are not taken to short-circuit the climate change.

He goes on to show two kinds of systematic change in climate: the averages have shifted and, at the same time, the odds of extreme events occurring have increased dramatically. This, of course, is the significance of his title: the climate dice have been loaded (biased) by global warming. He presents details of the changes which have already occurred and notes that, “The climate dice are now loaded to a degree that the perceptive person (old enough to remember the climate of 1951-1980) should be able to recognize the existence of climate change.” In particular, people should be noticing that extreme weather is far more common than it ever used to be.

He doesn’t quite ask, “Why don’t they notice?” but the question hovers there, waiting for an answer.

I have been trying to answer it myself since a random conversation a year ago. I was chatting to a youngish, intelligent person with a degree in natural sciences and a job in  GBRMPA, which looks after the Great Barrier Reef. I was quite surprised to find that she had not actually observed the effects of climate change. Then I found that she had spent her first ten years on a Pacific island, her next eight in Sydney, and another eight or so here in Townsville, so she hadn’t actually been anywhere long enough to notice a change in that location.

As I thought about that, I realised that she has lots of company. There are far fewer people who might reasonably be expected to notice climate change than we might at first think. A quick estimate goes like this:

  • Age group really has to be 40+, since anyone under ten in the early 1980s won’t remember the old norms. Change has occurred in the last thirty years, but it is the comparison with the pre-1980 baseline which makes it stand out strongly. That rules out more than 50% of the world’s population and perhaps even more than 50% of the world’s voters.
  • But also, those people have to have been living in the same general area for 40+ years, or have returned to it after some time away, because no-one in California will say, “It wasn’t like this when I was a kid,” if they grew up in Normandy, Queensland or even Virginia. How many Westerners are that stable? 50%?
  • Furthermore, the closer we live to nature, the more likely we are to notice its changes – but more and more of us are urbanised. Europe, Australia and the US are all more than 80% urbanised according to UN stats, while China, India and most of the developing nations are less than 40% urbanised. How many of the 50% of 50% are therefore likely to qualify as “perceptive”? Less than 50% in the West, certainly; perhaps more than 50% in less urbanised countries.
  • That leaves less than 10% of the world’s population in a position to recognise climate change from personal observation. And (unfortunately for the debate) most of those 10% are the rural poor of developing nations, the most frequent victims of climate change not the opinion-makers of industrialised nations.

Of course, Hansen’s statistics show that extreme weather events are going to increase very rapidly in number and severity as global warming continues. More and more of us will notice the effects in our daily lives. But that is not really good news.

Climate change and extreme weather events

For the last few years I, among others, have been looking at the news and wondering to what extent this, that or the other extreme weather event – the 2010 Russian heatwave, the Queensland floods, record flooding in Thailand, etc – was due to climate change. When I asked those who ought to know, the response was always, “There is probably some influence there but it is too hard to disentangle from natural variation, so you can’t just say that it was caused by global warming,” or words to that effect. A typical scientific response, in relation to the Queensland floods, is here.

This week RealClimate reported on a scientific paper by Stefan Rahmstorf and Dim Coucou which puts statistically verifiable numbers on the feeling that, yes, global warming is making our weather more extreme. RealClimate’s report is a (relatively) non-technical introduction to the findings and it is linked to the paper itself if you want more.

My really short, really non-technical summary is that the number of record-breaking events increases in proportion to the rate at which the normal (average) conditions are changing. That matches my gut feeling very well, which naturally pleases me. But it simultaneously alarms me because it means that record-breaking events are going to get more and more frequent unless we can quickly and radically reduce our CO2 emissions.

Back to the science: the authors applied their technique to the Russian heatwave and found, “an approximate 80% probability that the 2010 July heat record would not have occurred without climate warming.” That quote is from  the abstract of the paper, meaning that it is in careful scientific language, i.e. there is an approximate 99.9% probability that they can back up every word of it.

The Comments on RealClimate posts are usually well worth reading. Two caught my eye this time:

(1) Ricky Rood looks at other ways in which the 2010 Russian heat wave was extreme: http://www.wunderground.com/blog/RickyRood/comment.html?entrynum=208.

The winter of 2010 and the spring of 2011 were characterized by very high food prices. An essay by Sarah Johnstone and Jeffrey Mazo entitled, Global Warming and Arab Spring, draws a convincing line that the pressure on food prices was a contributor to the start of the revolutions of the Arab Spring – the tumultuous uprising against many Arab governments. (also here) To diffuse the arguments that are sure to follow – this was a contributor, along with many other factors that came together to fuel a movement. This is the idea of climate extremes as a threat multiplier.

(2) Pete Dunkelberg says:

For a first approximation, an outlier [i.e. extreme event] in the direction of a trend tells you what’s coming. … Just from the shape of a bell curve (and this is far from original) one can see that you don’t have to move the mean very far in one direction for outliers on that side to become much more frequent. A one hundred year heat wave or flood readily becomes a ten or five year event. The new hundred year flood is going to drown people.

Now, how did that Chinese curse go? “May you live in interesting times” – was that it?