In my last post, I discussed a new peer-reviewed paper by climate scientists Kevin Anderson and Alice Bows. It paints a grim picture:

The commonly accepted threshold of climate “safety,” 2 degrees C [3.6 degrees F] temperature rise over pre-industrial levels, is now properly considered extremely dangerous;

even 2 degrees C is drifting out of reach, absent efforts of a scale and speed beyond anything currently proposed;

our current trajectory is leading us toward 4 or 6 (or 8 or 10) degrees C, which we now know to be a potentially civilization-threatening disaster.

Like I said, go ahead and pour yourself a stiff drink.

So, what does this grim situation say about our current climate policy efforts? The paper also contains some important insights on that front. Here is how Anderson and Bows frame it:

Over the past five years a wealth of analyses have described very different responses to what, at first sight, appears to be the same question: What emission-reduction profiles are compatible with avoiding “dangerous” climate change? However, on closer investigation, the difference in responses is related less to different interpretations of the science underpinning climate change and much more to differing assumptions related to five fundamental and contextual issues. Get Grist in your inbox

Always free, always fresh The Beacon Other choices Ask your climate scientist if Grist is right for you. See our privacy policy (1) What delineates dangerous from acceptable climate change?

(2) What risk of entering dangerous climate change is acceptable?

(3) When is it reasonable to assume global emissions will peak?

(4) What reduction rates in post-peak emissions is it reasonable to consider?

(5) Can the primacy of economic growth be questioned in attempts to avoid dangerous climate change?

Keep question (5) in mind. It is almost never raised explicitly in these discussions, but it turns out to be central to how we answer the other questions.

Related: The brutal logic of climate change, international shipping edition ‘Brutal logic’ and climate communications The brutal logic of climate change

Long story short, Anderson and Bows argue that we are systematically blowing smoke up our own asses. (Though, ahem, that’s probably not how they would put it.)

The thing is, we have ostensibly answered question (1). The Copenhagen Accord has been signed by 141 countries representing over 87 percent of global emissions, including the U.S. and the E.U. It explicitly recognizes “the scientific view that the increase in global temperature should be below 2 degrees Celsius.” Climate communiques the world over are full of categorical language: we “must” avoid 2 degrees C! (Despite the fact that new science reveals 2 degrees C to be well within extremely dangerous territory.)

We pretend that 2 degrees C is our threshold. Yet the climate scenarios and plans presented to policymakers do not actually reflect that threshold. As Anderson and Bows say, “most policy advice is to accept a high probability of extremely dangerous climate change rather than propose radical and immediate emission reductions.”

Note, also, that most popular climate scenarios include an implausibly early peak in global emissions — 2010 in many cases, 2015-16 in the case of the Stern Report, the ADAM project, and the U.K.’s Committee on Climate Change.

Why do climate analysts do this? Why do they present plans that contain wildly optimistic assumptions about the peak in global emissions and yet a high probability of overshooting the 2 degrees C target?

The answer is fairly simple, and it has to do with the answer to question (4), regarding what level of emissions reductions is reasonable to expect. According to the Stern Review and others, emissions reductions of 3 to 4 percent a year are the maximum compatible with continued economic growth. And so that’s the level they use in their scenarios. Yet reductions at that pace offer very little practical hope of hitting 2 degrees C.

In other words, climate analysts construct their scenarios not to avoid dangerous climate change but to avoid threatening economic growth.

That would make sense if being richer would help us prosper in a 4 degrees C [7.2 degrees F] world. But … no such luck. Says Anderson in his slideshow presentation:

There is a widespread view that a 4 degrees C future is incompatible with an organised global community, is likely to be beyond “adaptation,” is devastating to the majority of ecosystems, and has a high probability of not being stable (i.e., 4 degrees C would be an interim temperature on the way to a much higher equilibrium level).

To be sure, there is plenty of uncertainty about the impacts of particular levels of temperature rise. (See: recent controversy over climate sensitivity.) Predictions are hard, especially about the future. But if the “widespread view” Anderson identifies is correct — or even half correct! — it completely scrambles conventional approaches to the problem. It implies that 4 degrees C must be avoided at literally any cost.

So, what would it mean to take that seriously? To create scenarios that actually do target 2 degrees C, or something very close to it, at a reasonably high degree of certainty?

To begin with, you’d want to stop lumping together the changes that developed nations and still-developing countries need to make. Many climate scenarios aggregate these numbers into a single global carbon reduction pathway, showing a global peak and decline. But that conceals the scale of the task facing rich industrialized economies. Things look different when the total carbon budget is divided between Annex 1 and non-Annex 1 countries (to use the U.N. jargon).

Say our carbon budget for the century is 2,000 gigatons. How much of that should be allotted to the U.S. and E.U., and how much to countries like China and India? Should it be divided up based on population (i.e., per-capita)? Past emissions? Present emissions? A thousand gigatons each?

If we widen our view to this century and last century, an argument could be made that the developed world has already spent its fair share of the carbon budget — that it’s in carbon debt, as it were.

Mongabay

China currently emits more than the U.S. on an absolute basis, but historically speaking, Annex 1 countries have emitted far, far more carbon. And they’ve benefited by becoming extraordinarily wealthy. Developing nations, by contrast, have spent far less and are still busy bringing millions of people out of abject poverty.

It’s impractical to think developed countries are going to stop emitting on a dime, but it seems clear that they are at least due a smaller portion of the remaining budget. If nothing else, just as a practical matter, rich countries are capable of more rapid emission reductions. In U.N. jargon, this is known as the “principle of common but differentiated responsibilities.”

So non-Annex 1 countries get more of the carbon budget that’s left. That recasts the task facing countries like the U.S. in an even harsher light.

Say global emissions must peak by 2020 to have any chance of avoiding dangerous climate change. There’s no way in hell China et al. are going to peak their emissions by then — not practically, not morally. So we decide to give non-Annex 1 countries until 2025 to peak (that is, to put it charitably, at the very outer edge of the realm of the possible). If that’s true, developed countries must compensate by peaking before 2015.

I’ll give you a second to check your calendar. … Yup! You are correct that 2015 is a mere three years away.

(The paper gets into considerable detail about a variety of scenarios for Annex 1 and non-Annex 1 countries, depending on treatment of variables like deforestation and CO2-equivalent gases. Dig in if you like, but the above works as an approximation.)

Soooo … where does that leave us? What would it mean for the U.S. and other developed countries to peak their emissions in 2015 and decline them by something on the order of 10 percent a year thereafter?

It’s safe to say that no carbon tax is going to do that. It’s tough to imagine any “market mechanism” that could ratchet things so quickly, at least on its own. We won’t get there through innovation or new technology, even if we spend a trillion a year for the next few years. We won’t get there by tweaking our current system. The only conceivable way to produce that level of reductions is a full-scale, all-hands-on-deck mobilization, what William James called “the moral equivalent of war.”

The vast bulk of the reductions available in the near-term are on the demand side. Of course this means driving efficiency as fast as possible while taking measures (like raising prices and setting standards) to avoid the rebound effect. But it also means (gasp!) conservation. Actually, “conservation” is too polite a word for it. It means shared sacrifice. Climate campaigners have sworn until they’re blue in the face that reducing emissions is compatible with robust economic growth. And it’s true! But reducing emissions enough? Maybe not, at least not for the next little while.

This is the stark conclusion drawn by Anderson and Bows: “The logic of such studies suggests (extremely) dangerous climate change can only be avoided if economic growth is exchanged, at least temporarily, for a period of planned austerity within Annex 1 nations and a rapid transition away from fossil-fuelled development within non-Annex 1 nations.”

I know what you’re thinking. It’ll never happen. It’s political suicide to bring it up. Conservatives will use it against us. Very Serious People will take to fainting couches across the land. I’ll address those questions in my next post.

But for now, it’s enough to say: It is what it is. As Anderson says, we’re currently mitigating for 4 degrees C and planning for 2 degrees C. That is deranged. We need to be doing the opposite — mitigating for 2, planning for 4 — as soon as possible.