by Judith Curry
Current climate policy promises will do little to stabilize the climate and their impact will be undetectable for many decades. – Bjorn Lomborg
Bjorn Lomborg has a new paper out in the Global Policy journal, Impact of Current Climate Proposals:
Abstract: This article investigates the temperature reduction impact of major climate policy proposals implemented by 2030, using the standard MAGICC climate model. Even optimistically assuming that promised emission cuts are maintained throughout the century, the impacts are generally small. The impact of the US Clean Power Plan (USCPP) is a reduction in temperature rise by 0.013°C by 2100. The full US promise for the COP21 climate conference in Paris, its so-called Intended Nationally Determined Contribution (INDC) will reduce temperature rise by 0.031°C. The EU 20-20 policy has an impact of 0.026°C, the EU INDC 0.053°C, and China INDC 0.048°C. All climate policies by the US, China, the EU and the rest of the world, implemented from the early 2000s to 2030 and sustained through the century will likely reduce global temperature rise about 0.17°C in 2100. These impact estimates are robust to different calibrations of climate sensitivity, carbon cycling and different climate scenarios. Current climate policy promises will do little to stabilize the climate and their impact will be undetectable for many decades.
Full text of the press release (see original for the figures):
Research Reveals Negligible Impact of Paris Climate Promises
A new peer-reviewed paper by Dr. Bjorn Lomborg published in the Global Policy journal measures the actual impact of all significant climate promises made ahead of the Paris climate summit.
Governments have publicly outlined their post-2020 climate commitments in the build-up to the December’s meeting. These promises are known as “Intended Nationally Determined Contributions” (INDCs).
Dr. Lomborg’s research reveals:
- The climate impact of all Paris INDC promises is miniscule: if we measure the impact of every nation fulfilling every promise by 2030, the total temperature reduction will be 0.048°C (0.086°F) by 2100.
- Even if we assume that these promises would be extended for another 70 years, there is still little impact: if every nation fulfills every promise by 2030, and continues to fulfill these promises faithfully until the end of the century, and there is no ‘CO₂ leakage’ to non-committed nations, the entirety of the Paris promises will reduce temperature rises by just 0.17°C (0.306°F) by 2100.
- US climate policies, in the most optimistic circumstances, fully achieved and adhered to throughout the century, will reduce global temperatures by 0.031°C (0.057°F) by 2100.
- EU climate policies, in the most optimistic circumstances, fully achieved and adhered to throughout the century, will reduce global temperatures by 0.053°C (0.096°F) by 2100.
- China climate policies, in the most optimistic circumstances, fully achieved and adhered to throughout the century, will reduce global temperatures by 0.048°C (0.086°F) by 2100.
- The rest of the world’s climate policies, in the most optimistic circumstances, fully achieved and adhered to throughout the century, will reduce global temperatures by 0.036°C (0.064°F) by 2100.
What does this mean for the Paris Summit?
Dr. Lomborg said: “Paris is being sold as the summit where we can help ‘heal the planet’ and ‘save the world’. It is no such thing. If all nations keep all their promises, temperatures will be cut by just 0.05°C (0.09°F). Even if every government on the planet not only keeps every Paris promise, reduces all emissions by 2030, and shifts no emissions to other countries, but also keeps these emission reductions throughout the rest of the century, temperatures will be reduced by just 0.17°C (0.3°F) by the year 2100.
And let’s be clear, that is very optimistic. Consider the Kyoto Protocol, signed in 1997, never ratified by the US, and eventually abandoned by Canada and Russia and Japan. After several renegotiations, the Kyoto Protocol had been weakened to the point that the hot air left from the collapse of the Soviet Union exceeded the entire promised reductions, leaving the treaty essentially toothless.
The only reason Kyoto goals were almost achieved was the global 2008 recession. Moreover, emissions were shifted from one country to another. The EU, the most climate-engaged bloc, saw an increase in its emission imports from China alone equaling its entire domestic CO₂ reductions. In total, 40% of all emissions were likely shifted away from the areas that made promises.
Negotiators in Paris are trying to tackle global warming in the same way that has failed for 30 years: by making promises that are individually expensive, will have little impact even in a hundred years and that many governments will try to shirk from.
This didn’t work in Kyoto, it didn’t work in Copenhagen, it hasn’t worked in the 18 other climate conferences or countless more international gatherings. The suggestion that it will make a large difference in Paris is wishful thinking.”
What should countries do instead?
Dr. Lomborg said: “Instead of trying to make fossil fuels so expensive that no one wants them – which will never work – we should make green energy so cheap everybody will shift to it.
The Copenhagen Consensus on Climate project gathered 27 of the world’s top climate economists and three Nobel Laureates, who found that the smartest, long-term climate policy is to invest in green R&D, to push down the price of green energy.
Subsidizing inefficient renewables is expensive and doesn’t work. The IEA estimates that we get 0.4% of our energy from wind and solar PV right now, and even in optimistic scenarios the fraction will only rise to 2.2% by 2040. Over the next 25 years, we’ll spend about $2.5 trillion in subsidies and reduce global warming temperatures by less than 0.02°C.
Copenhagen Consensus has consistently argued for a R&D-driven approach. Fortunately, more people are recognizing that this approach is cheaper and much more likely to succeed –including the Global Apollo Program which includes Sir David King, Lord Nicholas Stern, Lord Adair Turner and Lord John Browne.
You describe a 0.05°C reduction, but the UN Climate Chief, Christina Figueres, said Paris could lead to a 2.7°C rise instead of 4°C or 5°C. Why?
Christiana Figueres quote: “The INDCs have the capability of limiting the forecast temperature rise to around 2.7 degrees Celsius by 2100, by no means enough but a lot lower than the estimated four, five, or more degrees of warming projected by many prior to the INDCs.”
Dr. Lomborg said: “That entirely misrepresents the world’s options. The 2.7°C comes from the International Energy Agency and essentially assumes that if governments do little in Paris and then right after 2030 embark on incredibly ambitious climate reductions, we could get to 2.7°C.
That way of thinking is similar to telling the deeply indebted Greeks that just making the first repayment on their most pressing loans will put them on an easy pathway to becoming debt-free. It completely misses the point.
Figueres’ own organization estimates the Paris promises will reduce emissions by 33Gt CO₂ in total. To limit rises to 2.7°C, about 3,000Gt CO₂ would need to be reduced – or about 100 times more than the Paris commitments (see figure below). That is not optimism; it is wishful thinking.
UNEP
The UNEP has just published its Emissions Gap Report. Carbon Brief has an overview article Look beyond emissions gap to see full force of climate pledges, says UNEP report. Excerpts:
Climate pledges submitted to the UN reduce the emissions gap between current action and what is needed to avoid dangerous climate change, with social and political effects that reach far beyond their impact on aggregate emissions.
That’s the optimistic conclusion of the latest UN Environment Programme (UNEP) Emissions Gap Report, published this morning. Nevertheless, it confirms that the collective ambition of Intended Nationally Determined Contributions (INDCs) is “far from enough”, leaving a “very significant” emissions gap in 2030.
Like last week’s report, UNEP concludes that the INDCs represent a real increase in ambition, compared to the policies in place before the pledges were made.
Some of the INDCs include both conditional and unconditional elements. However, even if fully implemented, the INDCs would leave emissions on an upwards trajectory in 2030, UNEP says.
A gap of 12-14 gigatonnes of CO2 equivalent remains between emissions in 2030 and the cost-effective path to staying below 2C, it concludes. The 2C limit is the internationally agreed goal for avoiding the worst effects of climate change.
The chart illustrates why UNEP says current pledges are “far from enough”, leaving an emissions gap in 2030 that “will be very significant”. It says the INDCs, if fully implemented, would put the world on track for warming of around 3-3.5C by the end of the century.
Though this initially seems at odds with the 2.7C of warming by 2100 expected by the UNFCCC report, the difference comes down to how confident we can be in staying below those thresholds. Carbon Brief explored these differences in more depth last week.
So, there’s broad agreement — and, in fact, there has been for well over a year — that the aggregate impact of climate pledges in advance of Paris will fall short of securing the below-2C goal.
What’s interesting about the emissions gap report, however, is that UNEP seems keen to emphasise the indirect, positive impacts of the INDCs.
The reports says:
The social and political effects of the INDCs and the processes undertaken at national level transcend the aggregate effect they are estimated to have on total global greenhouse gas emission levels in 2025 and 2030. The preparation of the INDCs has in many countries incentivized exploration of linkages between development and climate, as well as development of new national climate policies, and can be seen as an important step in a transition towards low carbon economies.
JC comment: Wow, all this effort and spending for social and political effects. This brings to mind the Keystone pipeline affair in the U.S., and an insightful article in Vox What critics of Keystone campaign misunderstand about climate activism. Excerpts:
Plenty of people of good faith, even those who share a concern over climate change, are skeptical of, or at least puzzled by, the Keystone campaign. They all have versions of the same question: why this? It doesn’t seem like that big a deal in terms of carbon emissions. So why so much angst and organizing, so much wearying persistence, over this?
Read the article, there are some insights into the politics of all this.
Carbon accounting
Carbon accounting, Gt of C and CO2, is not something that I have personally been keeping track of. My go-to person on this is Mits Yamaguchi, who sent me the appropriate links in IPCC and UNFCCC reports. Here are the main salient points:
IPCC/AR5/WG1/SPM p. 27 states:
Limiting the warming caused by anthropogenic CO2 emissions alone with a probability of >33%, >50%, and >66% to less than 2°C since the period 1861.1880, will require cumulative CO2 emissions from all anthropogenic sources to stay between 0 and about 1570 GtC (5760 GtCO2), 0 and about 1210 GtC (4440 GtCO2), and 0 and about 1000 GtC (3670GtCO2) since that period, respectively. These upper amounts are reduced to about 900 GtC (3300 GtCO2), 820 GtC (3010 GtCO2), and 790 GtC (2900 GtCO2), respectively, when accounting for non-CO2 forcings as in RCP2.6. An amount of 515 [445 to 585] GtC (1890 [1630 to 2150] GtCO2), was already emitted by 2011. {12.5}
The UNFCCC Report says (page 18):
According to the AR5, the total global cumulative emissions since 2011 that are consistent with a global average temperature rise of less than 2 °C above pre-industrial levels at a likely (>66 percent) probability is 1,000 Gt CO2. Considering the aggregate effect of the INDCs, global cumulative CO2 emissions are expected to equal 54 (52.56) per cent by 2025 and 75 (72.77) per cent by 2030 of that 1,000 Gt CO2.
JC reflections
When I first saw Lomborg’s paper, I was surprised by the numbers he cites for the U.S., since they are somewhat smaller than the ones I have been citing (from Chip Knappenberger):
- The U.S. INDC of 28% reduction of emissions below 2005 levels by 2025 will prevent 0.03C in warming by 2100.
- Reducing U.S. total emissions by 80% by 2050 will prevent 0.11C in warming by 2100
The second, longer term reduction is not included in Lomborg’s analysis, for the following reason (cited in the paper):
For the following analyses we need to make assumptions about the longer-term promises. When for instance the EU promises to cut its emissions by 40 per cent in 2030, this is already very far away. Promises of what will happen in 2050 (80 per cent reduction in both the EU and the US) or promises for the G7 to entirely decarbonize by 2100 are not as much actual policies but more political hand waving. Thus, for this paper, I will investigate policies that have practical political implications soon and have a verifiable outcome by 2030, but not policies that promise actions only or mostly starting after 2030. Of course, policies that can be evaluated by 2030 will still impact emissions long after 2030, and hence affect the temperature trajectory all the way to the end of the century.
When I queried Lomborg specifically about the U.S. numbers, he provided this comment:
Also, note that a reduction by 80% in 2050 will cost the US about $1.2 trillion annually in lost GDP if politicians pick all the smart solutions (carbon tax etc). This is according to the Stanford Energy Modeling Forum 24, which ran 12 scenarios on 6 models to estimate the cost. This is 3.8% of GDP in 2050, and experience tells us that if politicians don’t do the smart thing, the cost will at least double (so about $2.4 trillion annually or 7.6% of GDP). Seems somewhat unlikely.
Lomborg also emphasized this point:
But when Figueres and IEA talk about 2.7°C, they’re assuming that we will cut a bit in Paris, but right after 2030, we’ll reduce emissions dramatically.
Lomborg’s ‘optimistic’ global warming reduction of 0.17C is consistent with a statement in the MIT Energy and Climate Outlook 2015:
Assuming the proposed cuts are extended through 2100 but not deepened further, they result in about 0.2C less warming by the end of the century compared with our estimates, under similar assumptions, for Copenhagen-Cancun.
So, I suspect that other economists will conduct similar studies and make different assumptions, maybe changing the net result even by as much a factor of two, given the range of possible assumptions to make in all this. But increasing the prevented warming by even a factor of two still puts this in the noise of what we could even detect against natural climate variability by the end of the 21st century.
Update: ThinkProgress has a critique of Lomborg’s paper [link]
All of these calculations are being made with the MAGICC model, assuming an ECS of 3C. My rationale for thinking that the ECS is lower than this value is described in this previous post Climate sensitivity: lopping off the fat tail. The impact of a slightly lower climate sensitivity (2.5C) is described in this recent post on the paper by Kaya and Yamaguchi in this recent post The uncertainty of climate sensitivity and its implication for the Paris negotiations. Lower values of ECS means even less warming is prevented by emissions reductions; it also means that the 2C target is in reach.
Lomborg’s paper is the first one published on the amount of warming prevented by the INDC commitments. I imagine that we will see many more analyses on this from economists, but I don’t see how the basic conclusion will change — the Paris INDC commitments will prevent a very small amount of warming by the end of the 21st century.
Filed under: Policy