Climate Doomsday Clock Winding Down

Time is running out to avert ‘dangerous’ climate change, says the IEA. But are deadlines and temperature targets too arbitrary?

We may be in for a world of hurt before this decade is out. The clock is now ticking on two nearly back-to-back deadlines that we are almost certain not to meet.

In 2006, NASA climate scientist James Hansen warned:

“I think we have a very brief window of opportunity to deal with climate change … no longer than a decade, at the most.”

That window is closing fast, and most climate observers say that significant action by 2016 is a reach. But wait: An extension of sorts has just been announced. Fatih Birol, chief economist at the International Energy Agency (IEA), now has tacked on a year, telling the Guardian:

“If we do not have an international agreement, whose effect is put in place by 2017, then the door to [holding temperatures to 2C of warming] will be closed forever.”


The 2C threshold has become a benchmark in climate policy. Staying below it means not exceeding 450 parts per million (ppm) of carbon dioxide in the atmosphere. But that seems increasingly doubtful as the world currently is at about 390 ppm and on a locked-in oil- and gas-dependent trajectory, according to a new report issued by the IEA. In its summary of the findings, the Guardian wrote:

The world is likely to build so many fossil-fuelled power stations, energy-guzzling factories and inefficient buildings in the next five years that it will become impossible to hold global warming to safe levels, and the last chance of combating dangerous climate change will be “lost for ever”, according to the most thorough analysis yet of world energy infrastructure.

But like the deadlines issued by Hansen and Birol, is the 2C threshold also an arbitrary target? Richard Betts, the head of Climate Impacts at the UK’s Met Office, thinks so. In a recent online discussion forum he asserted:

Most climate scientists do not subscribe to the 2 degrees “Dangerous Climate Change” meme (I know I don’t). “Dangerous” is a value judgment, and the relationship between any particular level of global mean temperature rise and impacts on society are fraught with uncertainties, including the nature of regional climate responses and the vulnerability/resilience of society.

Betts agrees that “climate change is a serious issue and it makes sense to try to avoid committing the planet to long-term changes.” But he’s concerned that the 2C benchmark sets up climate policymakers for certain failure. He says:

The thing that worries me about the talking-up of doom at 2 degrees is that this could lead to some very bad and expensive decisions in terms of adaptation. It probably is correct that we have about 5 years to achieve a peak and decline of global emissions that give a reasonable probability of staying below 2 degrees, but what happens in 10 years’ time when emissions are still rising and we are probably on course for 2 degrees?

One likely answer: The deadline gets pushed back another few years. By then, all the dire warnings either will have caused people to tune out or, if projected climate impacts worsen, to finally pay attention.

Keith Kloor

Keith Kloor is a New York City-based freelance journalist who writes often about the environment and climate change.
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10 Responses to Climate Doomsday Clock Winding Down

  1. klem says:

    And the timing of this IEA report has nothing to do with Durban next week.

    No, seriously.

  2. Bob Ward says:

    The rationale for the 2C target is not as arbitrary as you make out. But it is a target determined by policy-makers, albeit based on the science. The European Union has had the 2C target since at least 1996, and the scientific basis for it is highlighted in this document published in October 2010:

    The section on ‘Avoiding dangerous climate change’ begins with the following statement: “As has been found in the IPCC AR4 and reinforced in the EU 2C Target paper (EG Science 2008), if an increase in the global average temperature exceeds 2C, it becomes less likely that the majority of human systems can adapt to climate change at globally-acceptable economic, social and environmental costs.”

    There are a number of problems with Richard Betts’s comments, including the unsubstantiated claim that “most climate scientists” reject the 2C target. The biggest problem is that he frames the decision in terms of whetehr we are certain of the impacts instead of risks of impacts, and so makes the same rookie error as many other climate scientists who are largely oblivious to the excellent body of work on the communication of climate change (such as this paper by Pidgeon and Fischhoff:

    But returning to the 2C target, the assertion that we are bound to miss it is also suspect. The first thing to appreciate is that the link between a particular temperature rise and a change in concentrations or emissions is subject to large error bars, and so the practice has been to assess the probability of not exceeding 2C. It is clear from an analysis published by UNEP last November that current national emission pledges for 2020 are not consistent with having even a 50-50 chance of avoiding a rise of more than 2C, but if annual emissions peak in the next ten years and then decline by half by 2050, we could have an evens chance of meeting the target:

    • klem says:

      If so many of these statements are suspect, what is the unspoken reason they would continue to make them?

    • it is very apparent in my research with a very wide range of climate scientists that, with one exception, none of them believe in the idea of a 2 degree dangerous limit. Dangerous is a subjective term, it is simply not possible to reduce the complexity of the world, and the varied vulnerability and value systems of human communities to one metric. The 2 degree limit is an act of power which subjugates the world’s people to an elite definition of danger which does nothing more than delay having to take the necessary political and social changes. “Don’t worry, it’s a problem for the future, the experts have told you how much warming is acceptable and they are going to find some magic technologies which will allow for business as usual without CO2″. The WBGU reports of the mid 1990′s, key drivers in the EU’s adoption of 2 degrees, just said, oh well, look how much warming humanity survived in the past, add 0.5 degrees to that because now we are more adaptable really?) and hey presto, 2 degrees.

  3. Thanks Keith for your thoughtful comments around my post.

    Bob, thanks for your comments too. However, I think you are reading too much into what I said. I didn’t “frame the decision” in any terms – I didn’t talk about any decision. You seem to think that I was somehow questioning mitigation policy, but I definitely was not. I just pointed out that the scientific evidence is uncertain, and this must be recognised because the same science informs more than one policy area. My key point is that “dangerous climate change” does not lend itself to scientific definition, which is why most climate scientists steer clear of it. It’s a value judgement.

    You are over-stating what AR4 said about 2 degrees. The IPCC does not make specific statements on thresholds of dangerous climate change. Moreover, while WG2 made a valiant attempt to try to frame the impacts assessments in a way which spoke clearly to Article 2 of the UNFCCC by presenting a table of impacts vs. levels of global warming, everybody (including the authors) recognised that it was a gross simplification and merely a first step rather than a definitive policy tool.

    BTW you say my statement about “most climate scientists” is unsubstantiated. OK, maybe I should have said “most climate scientists that I know” – but I bet I know more than you do! (I mean actual working-level climate scientists who crunch the numbers, plot the graphs and write the papers). However if you have evidence that most climate scientists do sign up to the 2 degrees value judgement then I’d be pleased to see it.

    On your last paragraph – yes I know that’s how it’s done, because I do it! I admit it is outside my field of expertise to comment on the likelihood of success of international negotiations in achieving a global peak and decline in emissions in time to avoid the probability of 2 degrees exceeding 50:50, so I probably should have said “if” not “when”. However, let’s re-cast my comment in the light of your comments about risk – there is already a substantial risk that we’ll exceed 2 degrees, and hence there is already a substantial risk that we will have to adapt to 2 degrees. Hence it is important that we are up-front about the uncertainties in what the impacts will be at 2 degrees so that we can be properly informed when we plan to adapt.

    • Bob Ward says:

      Hi Richard,

      I agree with much of what you have wriitten, which is a lot clearer and more thoughtful than your initial comments on the Bishop Hill blog. However, I think you are still wrong to characterise the 2C traget as a “value judgement”, which you contrast with a “scientific definition”.

      The 2C target is based on an assessment not just of the science, but also of the economics and all the other disciplines that are involved in assessing at what level of warming risks become unacceptable. As you acknowledge, climate scientists are unable on their own to assess what is a “dangerous level” but their findings are integral to the risk assessment process.

      I am rather puzzled by your continued claim that “most of the scientists you know” disagree with the 2C target. I assume you are including your colleagues at the Met Office, in which case, are you saying that most Met Office climate scientists disagree with the findings of the AVOID programme? The final report, which was published in March 2011, stated:

      “The results to date suggest that a high risk tolerance will be required if policy-makers are to stick with a 2°C target ceiling over pre-industrial global mean temperature, since several systems are at 50:50 or worse risk of ‘dangerous anthropogenic interference’ below, at, or just above the 2°C threshold, including aspects of Arctic, mountains, corals, and permafrost systems. Given that the greenhouse gas emissions reductions being proposed for a 2°C target typically provide an approximately 50:50 chance of keeping below the target, current emissions reduction targets imply significant risks to several of these systems.”

      • Hi Bob

        Please stop twisting my words.

        I didn’t say “most scientists I know disagree with the 2 degree target”.

        I said “most of the climate scientists (atmospheric physicists) I know do not subscribe to the 2 degrees ‘Dangerous Climate Change’ meme”. This is very different.

        My point is merely that defining Dangerous Climate Change is not a question for atmospheric physics, as it has socioeconomic and policy dimensions and it is important for the integrity of climate science to remain distinct from such areas.

        I must say that your persistance on this issue is rather worrying, as you seem to be trying to shut down legitimate scientific debate, which is unhealthy. The scientific uncertainties *should* be discussed openly, for the reasons I have explained.

        BTW the AVOID report you mention was an expert elicitation. The experts involved are all highly-regarded but even so the evidence upon which they based their statements is still subject to high uncertainty. I don’t see why citing this report conflicts with my statements.

  4. Ben Pile says:

    Bob Ward is wrong to claim that the 2 degree target is not arbitrary. As the literature he points to continues, “…if an increase in the global average temperature exceeds 2°C, it becomes less likely that the majority of human systems can adapt to climate change…”.

    The same can be said of a limit of 1.9 degrees, 1.8, 1.5, 1.0. And it cannot be said that we become more able to adapt to climate change as temperature approaches 2 degrees. Ergo, the 2 degree limit is arbitrary. 2 degrees is merely a horizon of un/certainty, not a point at which something happens.

    In terms of the ‘communication of climate change’ — which Bob Ward seems very fond of — the 2 degree limit is an application of the precautionary principle, by other means. Rather than saying ‘we don’t know what will happen if X…’, the uncertainties are inverted: ‘we know that we don’t know what will happen if X…’. Some people call this political spin. Donald Rumsfeld did the same thing with his famous ‘known unknowns’ speech about WMDs in Iraq.

  5. keith Kloor says:

    I didn’t see this Michael Levi post until after I finished mine. His is very much worth checking out:

    Here’s a taste:

    “The IEA report is an important warning that delay is imprudent and that a 450 ppm world is increasingly hard to imagine. But I think it goes too far. There are three important reasons to be skeptical of the 2017 deadline that it presents.”

  6. Alexander Harvey says:

    It is good of Richard Betts to take the time to comment here and at Bishop Hill’s place.

    My anxiety rests uneasily not on a global temperature goal but on our ability to react should things turn nasty. What levers could we pull should it become obvious that a line is being crossed?

    Let me say, for instance, that one of the major equatorial forests starts to die back at a rate that would see its effective demise in a generation. A tragedy not just for the forest but risk of an existential threat to a sovereign state.

    Should such occur, and it was suspected that it was due to climatic changes, what could we do to save that forest. Do such levers exist, could we pull them, would we pull them, how quickly would they work?

    Similarly, were there to be an obviously climate related ramping up of human mortality rates, say 10 million excess adult deaths per annum, how long would we be running global intensive care, if we even attempted that, before we could first stabilise the situtation and then hopefully compensate?

    Should we find that there comes a point whereafter, a climate related release of methane is ongoing and not self-limiting, how long would it be before we could take the necessary steps to regulate it?

    To put it most simply, could we fly the planet in hazardous meteorological conditions?