Friday, March 13, 2015

Are emissions stabilised?

Today the International Energy Agency has published  data about last year's carbon dioxide emissions. They stand at 32.3 billion tonnes, the same as the year before.

This would be good news if it signalled a global trend, which would be a complete surprise. Stabilising carbon emissions is the goal of international climate policy which has proven elusive over the past decades. Common wisdom is that we will see many years of rising emissions globally before a plateau is in sight.

So what to make of this announcement? The IEA says the halt is due to a variety of factors:

The IEA attributes the halt in emissions growth to changing patterns of energy consumption in China and OECD countries. In China, 2014 saw greater generation of electricity from renewable sources, such as hydropower, solar, wind and less burning of coal. In OECD economies, recent efforts to promote more sustainable growth – including greater energy efficiency and more renewable energy – are producing the desired effect of decoupling economic growth from greenhouse gas emissions.
No details of the analysis are provided, they are promised for a report due in June. The incoming executive director of IEA, Fatih Birol said:

"This is both a very welcome surprise and a significant one... It provides much-needed momentum to negotiators preparing to forge a global climate deal in Paris in December: for the first time, greenhouse gas emissions are decoupling from economic growth."

The IEA is careful to point out that the stabilisation is not due to an economic crisis:

In the 40 years in which the IEA has been collecting data on carbon dioxide emissions, there have only been three times in which emissions have stood still or fallen compared to the previous year, and all were associated with global economic weakness: the early 1980's; 1992 and 2009. In 2014, however, the global economy expanded by 3 percent.

This is interpreted as a clear sign that carbon emissions and economic growth have become uncoupled. But two years don't make a trend. We have seen long and sometimes bitter debates about the global temperature trend over a decade or more, and about its significance. The emissions data might add another point of contention.

It is a potential bombshell. If emissions are stabilising in the absence of a global climate treaty such an undertaking would not be needed after all. On the other hand, diplomats and politicians might be persuaded to sign a deal which merely affirms what has been achieved, or what seems to be achievable with little effort.


Martin Heimann said...

Unfortunately stabilising emissions does not stabilise concentrations. A substantial reduction in the emissions is needed to stabilise CO2 concentrations. A subtle, but critical detail...

@ReinerGrundmann said...

You are of course right. I should have made this clearer. After all, also constant emissions will add to exisiting emissions and thereby increase overall concentration.

Nevertheless, IF emissions stay flat, the challenge would look more manageable (people will know which of IPCC scenarios apply in such a case).

But if the issue is perceived more manageable compared to what we think now (or thought until yesterday) no clear policy consequences follow. Birol warns against complacency, sensing that some might see this as a reason to do less mitigation policy.

Martin Heimann said...

I agree. In any case it's a big IF. If you look at the emissions and their growth rate (see link below), any flattening is clearly not yet perceivable.

Karl Kuhn said...

Ross McKitrick had a paper on this problem in 2013 that gives a clue why emissions might peak earlier than expected:

McKitrick, Ross and Joel Wood (2013) Co-fluctuation patterns of per capita carbon dioxide emissions: The role of energy markets. Energy Economics doi:10.1016/j.eneco.2013.03.015

"Our conjecture is that the emergence of increasingly-integrated global energy markets worldwide has increased the transmission of price signals across countries, so that growing fuel consumption in one region forces up prices in other regions and induces offsetting emission reductions elsewhere. This leads to the co-fluctuation patterns referred to in the title. We tested this by using PC analysis to construct an index of the linkages of emission fluctuations across countries and found evidence that they have become more linked over time and across wider geographic regions. We also found evidence that price signals are likely the coordinating forces. This means that emissions scenarios (like the ones the IPCC uses) that allow emissions to grow rapidly in one region without inducing offsetting reductions elsewhere are missing a key mechanism that applies in the real world, which would constrain the growth of overall emissions. Current emissions per capita are around 1.3 tonnes per person globally. The IPCC uses emission scenarios that are reasonable through this decade, but which diverge starting around 2020, with the top end going to between 30 and 40 Gigatonnes of emissions globally. Since world population is expected to peak at around 10 billion people, this requires emissions per capita to reach between 3 and 4 tonnes, a target that appears economically impossible. Instead, emissions per capita will likely remain in the neighbourhood of 1.3 tonnes per person (give or take a few tenths), implying peak global emissions of around 15 to 20 Gigatonnes, half the IPCC peak range. So we deem the lower half of the forecast range more likely than the upper half."

@ReinerGrundmann said...

Very interesting observation by McKitrick and thanks for sharing. However, how does this line of reasoning square with the dramatic fall in fossil fuel prices since last summer?

Georg Hoffmann said...

"Instead, emissions per capita will likely remain in the neighbourhood of 1.3 tonnes per person (give or take a few tenths), "

Why? Did I miss a point? Do I have to read the full paper at the end?

ruedi said...

Easy: The invisible hand of the liberated energy market, the desire for the IPCC scenarios being too pessimistic plus a "PCA based index" will do the trick :).

Georg Hoffmann said...

Uff. I was afraid it's something profound and surprising.

Karl Kuhn said...

Sorry for not responding earlier ... well, reading the intro and summary of the paper is certainly not a bad idea for open minds, and also this paper, as it is more or less the prelude to the one I mentioned above:

"Long-Term Forecasting of Global Carbon Dioxide Emissions: Reducing Uncertainties Using a Per Capita Approach"

McKitrick's point is that per-capita emissions tend to be more stable on the global level than one might think. I still believe that his claim that we might not much exceed 1.3 ton per person and year is too bold.

I am just doing some simple calculations on population and economic growth and their functional links to carbon dioxide emissions. The crucial point is that you have this U-shaped trend of emissions per unit of GDP when countries grow out of poverty. I will let you know whether something comes out.

ruedi said...

OK, not fair. The paper appears technically sound enough; they don't abuse the PCA; nice idea, nice argument. It is a qualitative argument, slight mathturbatory stench with maybe fishy "significances" attached to effects of hard to interpret size. Just as you find in cli. sci. literature every day.

But if you read the paper, you'll find that it contains *nothing* of what Karl is "quoting" above. That text stems from the author's website. And it is bullshit, because the main "conclusion" there, i.e., stationary per capita emissions, is a crucial assumption, set a priori, to carry out the analysis in the paper in the first place.

Profound and surprising is maybe the chuzpe to publish on the web that version of the conclusion of your new paper that would never have passed peer review.

Karl Kuhn said...

As to the emission data I looked at:

The 29 countries with GDP per capita of more than 18605 US$ (average of 2008-2010, WDI database) have average per-capita emissions of 2,57 tons of carbon(not CO2, BTW!). The lowest value is that of Switzerland with 1,42. This is still above the global average of 1,26 (according to that database). So it is unlikely that emerging economies will not further increase their per-capita emissions once they catch up to high income countries.

These high-income countries, however, seem to have started to reduce their per-capita emissions, particularly EU and US, albeit for different reasons. They have decoupled growth from CO2 emissions. This is not yet the case for emerging economies. Still, it seems that wealthy countries might not further contribute to growth in emissions in the coming decades, regardless of their future growth or political efforts to reduce emissions. But this would indicate that - assuming long-term global convergence of per-capita GDP - the world would rather settle at about 2.5 metric tons per capita instead of McKitrick's 1.3 (my main criticism of his paper is that he restricted his investigation period to prior-2000, i.e. the period during which per-capita emissions were indeed flat. Of course it is interesting to see why this stationarity persisted for so long, and the paper delivers a reasonable explanation, but the recent upward trend driven mainly by China may not be just a short-term anomaly). And that total global emissions are about to peak soon is something I can't see from the recent trends.

@ Reiner Grundmann:

I guess that the current low oil price level (resulting from additional supply from unconventional sources and the Saudis' fight against those) will at least not contribute to peaking CO2 emissions.

Anonymous said...

The discussion seems to be about some aspects of the Kaya identity (without mentioning it). Instead of calling names ("bullshit" and the like) against all rules of ettiquette here, I would be rather happy if both a well known sceptical scientist like Ross McKitrick or e.g. a lukewarmer like Pielke junior, would reach comparable conclusions.

First some comments on the IAE statement and the ongoing dicussion.

I have slight doubts about the IAE stating combat climate change were "the most important threat facing us today". Try violent ideologies, corruption, infectious deseases, natural hazards (a Tsunami now and then) and lack of good governance, basic food, water, energy, and health care supply instead.

The IAE data are about the anthropogenic carbon emissions. Just the allegedly natural (in reality, its via land use patterns as well human induced and influenced) decay of organic material in forests and grasslands and the action of forest fires results in the release of about (quoting WP's entry on Carbon dioxide in Earth's atmosphere) more than 400 gigatonnes of carbon dioxide every year, new growth counteracts this effect, with a similar amount. That said, industry is important, but land use has - ask Pielke senior- a larger effect. Its sort of contentious to divide natural and anthropogenic causes, as once in the atmosphere, carbon dioxide and other greenhouse gasses underlies the same "Chatelier principle", a higher supply will strengthen the demand side.
With regard to the Kaya identity, even China's growing economy has (see Pielke junior) a tendency to decouple GDP and carbon emissions.

Better do not put too much hope on savings. There are two earth science paradoxes here: a) The "Jevon's paradox" - gains in efficiency in the use of a certain raw material leads to higher consumption, not the other way round. b) The Julian Lincoln Simons paradox: Renewables may have run out historically, from wood till whale oil, but never ever mineral ressources. To the contrary, the availability of elementary raw materials (from metals till semiconductors) has always increased in the long run. Current prices are (inflation adjusted) way lower than in the historical past. Its true even for oil - the 20th century and recent price spikes never topped the inflation adjusted maxima in the late 19th century. Compare BP's historical data in WP commons "Crude_oil_prices_since_1861.png".
That said, if the IAE states that there is a halt in emissions growth its - from my point of view - about the way economic production is being organized. We seem to need less energy/raw materials and are able to use and distribute ideas and innovation without requiring the same amount of energy as in the past. Thats just great. But surely that is not based on neomalthusian ideology Naomi Klein and others won't like the background too much - as it is closely connected with globalization and technical and social innovation ;)

Regards Friedrich

Anonymous said...

Correction: The oil price record high of $147 in July 2008 bet the 19th century maximum. But see the Simmons–Tierney_bet for the confirmation of the Simons assumption. I still assume that lower Oil prices will not hamper a lower Carbon footprint, since the decoupling goes in both directions. Friedrich