aTTP falsely attacks Bjorn Lomborg’s “Impact of Current Climate Proposals” Paper

The following is a comment to be posted at Bishop Hill, responding to another attempt by blogger ….andThenThere’sPhysics to undermine the work of Bjorn Lomborg. The previous attempt was discussed here. This post includes a number of links, as well as a couple of illustrative screen captures at the foot of the table.

aTTP’s comment is

In fact, you should read Joe Romm’s post about this. He’s showing that the INDCs are likely to lead to around 3.5C which I think is relative to something like the 1860-1880 mean. This is very similar to the MIT’s 3.7, and quite a bit lower than the RCP8.5 of around 4.5C. So, yes, we all know that the INDCs are not going to do as much as some might like, but the impact is likely to be a good deal greater than that implied by Lomborg who has essentially assumed that we get to 2030 and then simply give up.

Nov 11, 2015 at 9:31 AM | …and Then There’s Physics

My Comment

aTTP at 9.31 refers to Joe Romm’s blog post of Nov 3 “Misleading U.N. Report Confuses Media On Paris Climate Talks“. Romm uses Climate Interactive’s Climate Scoreboard Tool to show the INDC submissions (if fully implemented) will result in 3.5°C as against the 4.5°C in the non-policy “No Action” Scenario. This is six times the claimed maximum impact of 0.17°C claimed in Lomberg’s new paper. Who is right? What struck me first was that Romm’s first graph, copied straight from the Climate Interactive’s seem to have a very large estimate for emissions in the “No Action” Scenario producing. Downloading the underlying data, I find the “No Action” global emissions in 2100 are 139.3 GtCO2e, compared with about 110 GtCO2e in Figure SPM5(a) of the AR5 Synthesis Report for the RCP8.5 scenario high emissions scenario. But it is the breakdown per country or region that matters.

For the USA, without action emissions are forecast to rise from 2010 to 2030 by 40%, in contrast to a rise of just 9% in the period 1990 to 2010. It is likely that emissions will fall without policy and will be no higher in 2100 than in 2010. The “no action” scenario overestimates 2030 emissions by 2-3 GtCO2e in 2030 and about 7-8 GtCO2e in 2100.

For the China the overestimation is even greater. Emissions will peak during the next decade as China fully industrializes, just as emissions peaked in most European countries in the 1970s and 1980s. Climate Interactive assumes that emissions will peak at 43 GtCO2e in 2090, whereas other estimates that the emissions peak will be around 16-17 GtCO2e before 2030.

Together, overestimations of the US and China’s “No Action” scenarios account for over half 55-60 GtCO2e 2100 emissions difference between the “No Action” and “Current INDC” scenarios. A very old IT term applies here – GIGO. If aTTP had actually checked the underlying assumptions he would realise that Romm’s rebuttal of Lomborg based on China’s emission assumptions (and repeated on his own blog) are as false as claiming that the availability of free condoms is why population peaks.

Links posted at

Kevin Marshall


Figures referred to (but not referenced) in the comment above

Figure 1: Climate Interactive’s graph, referenced by Joe Romm.

Figure 2: Reproduction of Figure SPM5(a) from Page 9 of the AR5 Synthesis Report.


Update – posted the following to ATTP’s blog


Global Emissions Reductions Targets for COP21 Paris 2015

There is a huge build-up underway for the COP21 climate conference to be staged in Paris in November. Many countries and NGOs are pushing for an agreement that will constrain warming to just 2oC, but there are no publicly available figures of what this means for all the countries of the world. This is the gap I seek close with a series of posts. The first post is concerned with getting a perspective on global emissions and the UNIPCC targets.

In what follows, all the actual figures are obtained from three primary sources.

  • Emissions data comes from the Carbon Dioxide Information Analysis Centre or CDIAC.
  • Population data comes from the World Bank, though a few countries are missing. These are mostly from Wikipedia.
  • The Emissions targets can be found in the Presentation for the UNIPCC AR5 Synthesis Report.

All categorizations and forecast estimates are my own.

The 1990 Emissions Position

A starting point for emissions reductions is to stabilize emissions to 1990 levels, around the time that climate mitigation was first proposed. To illustrate the composition emissions I have divided the countries of the world into the major groups meaningful at that time – roughly into First World developed nations, the Second World developed communist countries and the Third World developing economies. The First World is represented by the OECD. I have only included members in 1990, with the USA split off. The Second World is the Ex-Warsaw pact countries, with the countries of the former Yugoslavia included as well. The rest are of the world is divided into five groups. I have charted the emissions per capita against the populations of these groups to come up with the following graph.

In rough terms, one quarter of the global population accounted for two-thirds of global emissions. A major reduction on total emissions could therefore be achieved by these rich countries taking on the burden of emissions reductions, and the other countries not increasing their emissions, or keeping growth to a minimum.

The 2020 emissions forecast

I have created a forecast of both emissions and population for 2020 using the data up to 2013 for both emissions and population. Mostly these are assuming the same change in the next seven years as the last. For emissions in the rapidly-growing countries this might be an understatement. For China and India I have done separate forecasts based on their emissions commitments. This gives the following graph.

The picture has changed dramatically. Population has increased by 2.4 billion or 45% and emissions by over 80%. Global average emissions per capita have increased from 4.1 to 5.2t/CO2 per capita. Due to the population increase, to return global emissions to 1990 levels would mean reducing average emissions per capita to 2.85t/CO2.

The composition of emissions has been even more dramatic. The former First and Second World countries will see a slight fall in emissions from 14.9 to 14.0 billion tonnes of CO2 and the global share will have reduced from 68% to 36%. Although total population will have increased on 1990, the slower growth than elsewhere means the share of global population has shrunk to just 19%. China will have a similar population and with forecast emissions of 13.1 billion tonnes of CO2, 33% of the global total.

The picture is not yet complete. On slide 30 of their Synthesis Report presentation the UNIPCC state

Measures exist to achieve the substantial emissions reductions required to limit likely warming to 2oC (40-70% emissions reduction in GHGs globally by 2050 and near zero GHGs in 2100)

The baseline is 2011, when global emissions were 29.74 billion t/CO2. In 2050 global population will be nearly nine billion. This gives an upper limit of 2.2 t/CO2 per capita and lower limit of 1.1 t/CO2 per capita.

To put this in another perspective, consider the proportions of people living in countries that need emissions targets based on greater than 2.2t/CO2 emissions per capita.

In 1990, it was just a third of the global population. In 2020 it will be three quarters. No longer can an agreement on constraining global CO2 emissions be limited to a few countries. It needs to be truly global. The only area that meets the target is Africa, but even here the countries of Algeria, Egypt, Libya, Tunisia and South Africa would need to have emission reduction targets.

Further Questions

  1. What permutations are possible if other moral considerations are taken into account, like the developed countries bear the burden of emission cuts?
  2. What targets should be set for non-fossil fuel emissions, such as from Agriculture? Are these easier or harder to achieve than for fossil fuels?
  3. What does meeting emission targets mean for different types of economies? For instance are emission reductions more burdensome for the fast-growing emerging economies that for the developed economies?
  4. What are the measures that IPCC claims exist to reduce emissions? Are they more onerous than the consequences of climate change?
  5. Are there in place measures to support the states dependent on the production of fossil fuels? In particular, the loss of income to the Gulf States from leaving oil in the ground may further destabilize the area.
  6. What sanctions if some countries refuse to sign up to an agreement, or are politically unable to implement an agreement?
  7. What penalties will be imposed if countries fail to abide by the agreements made?

Kevin Marshall

BBC understates Cost of Climate Policy by 45 to 50 times

The UNIPCC has just finished a major meeting in Copenhagen to put finalize the wording of their AR5 Synthesis Report. BBC News Environment correspondent Matt McGrath said

The IPCC says that the cost of taking action to keep the rise in temperature under 2 degrees C over the next 76 years will cost about 0.06% of GDP every year.

Over the same period, world GDP is expected to grow at least 300%

The figure of 0.06% of GDP (strictly Gross World Product) seemed a bit low. So I looked up the source of this quote.

The Synthesis Report states on pages 116-117

Estimates of the aggregate economic costs of mitigation vary widely depending on methodologies and assumptions, but increase with the stringency of mitigation (high confidence). Scenarios in which all countries of the world begin mitigation immediately, in which there is a single global carbon price, and in which all key technologies are available, have been used as a cost-effective benchmark for estimating macroeconomic mitigation costs. (Figure 3.4). Under these assumptions, mitigation scenarios that are likely to limit warming to below 2 °C through the 21st century relative to pre-industrial levels entail losses in global consumption —not including benefits of reduced climate change (3.2) as well as co-benefits and adverse side-effects of mitigation (3.5, 4.3) — of 1% to 4% (median: 1.7%) in 2030, 2% to 6% (median: 3.4%) in 2050, and 3% to 11% (median: 4.8%) in 2100, relative to consumption in baseline scenarios that grows anywhere from 300% to more than 900% over the century. These numbers correspond to an annualized reduction of consumption growth by 0.04 to 0.14 (median: 0.06) percentage points over the century relative to annualized consumption growth in the baseline that is between 1.6% and 3% per year.

Matt McGarth (or a press officer) has wrongly assumed that 0.06% of GDP is the reduction in output, whereas the Synthesis Report talks about a reduction in growth rate. At any rate of growth, the impact of .06% reduction in growth rates will mean output in 2100 will be 4.8% lower. We can put a monetary impact on this through to 2090. The World Bank estimates global output was $74,910 billion in 2013. To keep the figures simple I will assume that 2014 will be $75,000 bn. The figures are below for 2090.

With 1.94% growth global output in 2090 will be $323,038bn, about $14,774bn less than if there was 2% growth. Cumulatively a 0.06% reduction in growth would be $369,901bn. But a cost of 0.06% each year of global output, with 2% growth is a mere $8,087bn. Misstatement of the UNIPCC’s position understates the cumulative cost by 45.7 times.

Similarly, with 2.94% growth global output in 2090 will be $678,356bn, about $30,716bn less than if there was 3% growth. Cumulatively a 0.06% reduction in growth would be $644,144bn. But a cost of 0.06% each year of global output, with 3% growth is a mere $13,107bn. Misstatement of the UNIPCC’s position understates the cumulative cost by 49.1 times.

The BBC or the UNIPCC needs to issue a correction. The UNIPCC have at last recognized that policy will effect economic growth. It is way too low, particularly for the high-policy countries who are put at an economic disadvantage relative to those countries without policies. Now they need to also look at the additional estimated costs of low carbon energy, along with the hidden costs of regulation and failed policies.

Thanks to Joanne Nova for highlighting the quote.

Kevin Marshall