The United Nations Climate Change Conference (COP21) in Paris climate was preceded by a surge of studies and articles warning of a dismal future if we do not take strong policy action. One scenario in the IPCC’s Fifth Assessment Report (AR5) provides the basis for these: RCP8.5. Even a casual examination of this shows it to be a useful worst-case scenario, but not “business as usual”. {Revised on 10 Dec 2015.}
Contents
- Scenarios looking at our future.
- RCP8.5, the stuff nightmares are made from.
- More good news about energy.
- Conclusions
- More news about the shift from coal.
- Other posts in this series.
- For More Information.
(1) An introduction to scenarios about our future
In AR5 four Representative Concentration Pathways (RCPs) describe scenarios for future emissions, concentrations, and land-use, ending with radiative forcing levels of 2.6, 4.5, 6.0, and 8.5 W/m2 by 2100. Strong mitigation policies result in a low forcing level (RCP2.6). Two medium stabilization scenarios lead to intermediate outcomes: (RCP4.5, RCP6.0).
RCP8.5 gets the most attention. It assumes the fastest population growth (a doubling of Earth’s population to 12 billion), the lowest rate of technology development, slow GDP growth, a massive increase in world poverty, plus high energy use and emissions. For more about the RCPs see “The representative concentration pathways: an overview” by Detlef P. van Vuuren et al, Climatic Change, Nov 2011.
RCP8.5 assumes a nightmarish world even before climate impacts, resulting from substantial changes to long-standing trends. It provides AR5 with an essential worst case scenario necessary for conservative planning.
Unfortunately scientists often inaccurately describe RCP8.5 as the baseline scenario — a future without policy action: “a relatively conservative business as usual case with low income, high population and high energy demand due to only modest improvements in energy intensity” from “RCP 8.5: A scenario of comparatively high greenhouse gas emissions” by Keywan Riahi et al in Climate Change, November 2011, This is a material misrepresentation of RCP8.5. Scientists then use RCP8.5 to construct horrific visions of the future. They seldom mention its unlikely assumptions.
(2) About RCP8.5, the stuff nightmares are made from
(a) Rapid population growth
RP8.5 assumes population growth at the high end of the current UN forecasts: 80% odds of between 9.6 and 12.3 billion people by 2100 (Gerland, P. et al, Science 10 Oct 2014). Most of this growth occurs in Africa, assuming that the collapse in fertility seem in the rest of the world will not occur there (Iran’s fertility was 6.0% in 1980, it is ~1.6 now, below the replacement rate of 2.1).
Gerland makes a purely probabilistic forecast, without considering if Africa can support the same population density as China does today. Their high end forecast, used in RCP8.5, is that Nigeria’s population will grow from 175 million today to 1.5 billion in 2100. See this for more information about the Gerland 2014 forecast.
(b) Technological stagnation: back to the 19th Century’s coal-driven world
RCP8.5 assumes that the centuries long progress of technology will slow. Most importantly, it assumes that three centuries of evolution to ever more efficient energy sources reverses and we burn off almost all of Earth’s fossil fuel reserves.
RCP8.5 describes a hot dirty future for the world, in which coal use increases to become the major source of power for the world.
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There is an analytical basis for these forecasts. For example, see “Drivers for the renaissance of coal” by Jan Christoph Steckel et al in PNAS, 2015. The authors predict that coal use will increase not just in China and India, but also in fast-growing poor countries. There are a lot of poor nations in RCP8.5.
But this assumes that the long shift away from coal continues. Data from the Energy Information Agency shows that world coal consumption fell by 98 million short tons (1.2%) in 2012 (most recent data) following peaking in many nations, both poor and rich nations. North American use peaked in 2005; 2012 was down an astonishing 21% since then (USA use in Q1 2015 was down 24% from Q1 2005). Europe peaked in 2007, after 6 of its 9 largest coal-consuming nations peaked: UK and Poland in 2006; Czech, Germany, and Greece in 2007; and Turkey in 2011. Africa peaked in 2008 and Asia in 2011.
History shows that as poor nations grow into the middle income brackets, people become willing to pay for a cleaner environment. That often drives regulations on the mining and burning of coal, which raises its cost (in the US perhaps going to uneconomic levels). We see the first signs of that now in India and China. A March report by the Sierra Club describes the situation:
“From 2005 to 2012, worldwide coal-fired generating capacity boomed, growing at three times the previous pace. The increase in the global coal fleet was twice the size of the entire existing U.S. coal fleet. That boom is now busting. In India, projects shelved or cancelled since 2012 outnumber project completions by six to one, and new construction initiations are at a near-standstill. In both Europe and the U.S., the coal fleet is shrinking, with retirements outnumbering new plants. China faces a looming glut in coal-fired generating capacity, with plant utilization rates at a 35-year low.”
China has been the largest driver of global commodity consumption, including coal. Excluding China, world coal use is flat for 5 years, up only 13% for 10 years, and up only 7% in the previous 25 years (there is no Energy Information Agency data after 2012).
China has shown little concern about climate change, but air pollution from coal is a major public policy problem. “The cost of China’s reliance on coal: 670,000 smog-related deaths a year“. “Beijing to Shut All Major Coal Power Plants to Cut Pollution“. There are headlines like this almost monthly as public pressure grows for drastic action (see this Pew Research poll).
The Sierra Club report describes this and other drivers of China’s shift away from coal…
“Within China, the following policy trends are playing a significant role in determining future coal capacity: (1) Small Plant Replacement Policy, (2) air pollution mitigation, (3) economic restructuring, (4) expanding renewable, gas, nuclear, and hydro power sources, (5) climate policies, (6) energy efficiency initiatives, and (7) shifts in the regional distribution of generating capacity.”
Perhaps these trends will reverse, but that cannot logically be considered the “business as usual” scenario.
(c) Technological stagnation: energy efficiency
RCP8.5 assumes no decarbonization of world power sources from new technology (e.g., solar, wind, fission, fusion) or regulations to reduce not just climate change but also air pollution and toxic waste. Although possible, how likely is this? For example, use of solar and wind is skyrocketing as these technologies improve.
RCP8.5 also assumes a slowing of technological innovation, most clearly seen in energy use. By 2100 energy efficiency has improved only slightly, so that despite GDP being one-third lower than under RCP2.6, energy consumption is over twice as large. That breaks the decades long trend, as shown in this graph from “Reaching peak emissions” by Robert B. Jackson, Nature Climate Change, January 2016 (also see energy efficiency by nation from the World Bank). There is no reason to assume this progress will halt.
Update: Energy intensity (electricity use/GDP) has been declining in the US since 1976. Per capita electricity consumption has been declining in the US since 1999. See this April 2017 Bloomberg article for details (e.g., “most other developed countries have experienced a plateauing or decline in electricity use similar to that in the U.S. over the past decade.”).
(d) A more realistic view of our energy future
More speculatively, new technology to produce energy might lie in our future. There are dozens of advanced nuclear and fusion projects under development. A new report by Third Way describes that some have matured to the stage attracting private capital:
“The American energy sector has experienced enormous technological innovation over the past decade in everything from renewables (solar and wind power), to extraction (hydraulic fracturing), to storage (advanced batteries), to consumer efficiency (advanced thermostats). What has gone largely unnoticed is that nuclear power is poised to join the innovation list.
“A new generation of engineers, entrepreneurs and investors are working to commercialize innovative and advanced nuclear reactors. …Third Way has found that there are nearly 50 companies, backed by more than $1.3 billion in private capital, developing plans for new nuclear plants in the U.S. and Canada. The mix includes startups and big-name investors like Bill Gates, all placing bets on a nuclear comeback, hoping to get the technology in position to win in an increasingly carbon-constrained world.”
(3) Conclusions
The designers of the RCP’s made a methodological choice that was logical, but was either not understood or ignored by the IPCC’s authors. They started with targets for forcings and created scenarios that would produce them.
The RCP8.5 scenario assumes ominous breaks in several important and long-standing trends. As such it provides a valuable warning against complacency and a reminder to prepare for extreme outcomes. But that meant that there was no business as usual scenario, a critical component for forecasting. None of the RCPs is even remotely close to fulfilling this role.
Worse was the labeling — with no supporting analysis — of RCP8.5 as the business as usual scenario (see the history here). Doing so preceded AR5, as in “Compared to the scenario literature RCP8.5 depicts thus a relatively conservative business as usual case with low income, high population and high energy demand due to only modest improvements in energy intensity” from “RCP 8.5: A scenario of comparatively high greenhouse gas emissions” by Keywan Riahi et al in Climate Change, November 2011.
I have written a description of the year 2100 assuming continuation of existing trends — including substantial advances in fusion. It’s a non-analytical discussion piece, showing that there is a more plausible alternative to RCP8.5’s nightmarish world of 2100. It shows that we need another RCP, one describing a base case showing reasonable projection of current trends.
Preparing that requires extrapolating trends for GDP, population, energy intensity, sources of energy, etc — assuming no breakthroughs in technology (e.g., fusion, a male contraceptive pill) — then calculating the resulting forcing. This should be done by a multidisciplinary team (imo tapping too-narrow a disciplinary base is one of the most serious weakness in climate science today). The cost would be trivial compared to its benefits.
As COP21 has shown, the public policy debate about climate change is gridlocked. Repeating what we have already done, with higher volume, seems unlikely to break it. Let’s draw outside the box and try different tactics.
(4) News about the shift from coal
- Is our certain fate a coal-burning climate apocalypse? No!
- Manufacturing climate nightmares: misusing science to create horrific predictions.
- Good news! Coal bankruptcies point to a better future for our climate.
- Britain joins the shift from coal, taking us away from the climate nightmare.
- Good news from America about climate change, leading the way to success.
- Good news from China about climate change!
(5) Other posts in this series
- The bottom line: How we broke the climate change debates. Lessons learned for the future.
- Is our certain fate a coal-burning climate apocalypse? No!
- A story of the climate change debate. How it ran; why it failed.
- The 5 stages of grief for the failure of the climate change campaign.
- Climate scientists can restart the climate change debate & win: test the models!
- The climate change crisis, as seen from 2100 AD.
(6) For More Information
To understand the RCP’s and their use see “Temperature implications from the IPCC 5th assessment Representative Concentration Pathways (RCP)” by the UK Met Office (update: it is a dead link; they archived posts but not reports here). For a detailed look at RCP8.5 see “Scenarios of long-term socio-economic and environmental development under climate stabilization” by Keywan Riahia et al, Technological Forecasting and Social Change, September 2007 (gated). To better understand the evolution of IPCC’s scenarios I recommend this by John Nielsen-Gammon (Prof Atmospheric Science at Texas A&M and Texas State Climatologist).
David Middleton uses the RCP database to do some fascinating calculations, showing that RCP6.0 seems to be a more reasonable “worst plausible” scenario for the 21st century — rather than the coal-burning late 21st century of RCP8.5
If you liked this post, like us on Facebook and follow us on Twitter. For more information see The keys to understanding climate change.
(6) For a more detailed look at today’s extreme weather
To learn more about the state of climate change see The Rightful Place of Science: Disasters and Climate Change
This forecast by IPCC goes against all common sense. Even in my southern state the local utility which has huge coal plants is encouraging solar power by homeowners.
Can they really be this stupid, or are there other motives?
social bill,
Look at the new PNAS paper I cite, which has received much attention. The economic growth in the 21st C is forecast to be in the poorer nations, just as it has been since WWII. They assume that these nations will rely on the cheapest power sources — coal — following the fast growing nations (e.g., China, India) in the past decade. It’s a likely scenario. Increased use of current solar and wind tech are unlikely to offset this new coal use.
What they don’t adequately forecast, imo — is that rising nations (such as China and India) will follow us and convert away from coal. I think believe that China will not clean up its skies in the next 20 years is quite daft, a Kipling-like belief that the people of the East are different and less than us.
The other omitted factor is a wildcard: radically new tech. While probably insignificant in the next few decades, I believe the 2nd half of the 21st C will rely on new sources of energy (i.e., new nukes, fusion, etc).
Straight line forecasts always look impressive. They tend to be right over short time horizons, and always prove wrong over longer ones.
Another problem with forecasts of a coal-driven future
Space precluded mention of what might be the largest factor limiting coal use: world coal reserves might be far less than most people have been led to believe. We have mined most of the dense, high BTU coal. We are mining the remainder of the good stuff. We have vast reserves, but some large fraction of this might have the BTU content of Kitty Litter.
Too little research has been done to validate these reserves. For more about this, see these reports:
Here is the key paragraph from the last report (#4):
Very interesting!
Some aspects of coal electric I learned in the past few years:
1. compared to coal, natgas uses less carbon per unit of electric energy. (easier to burn natgas at high temperature and pressure -> high thermodynamic efficiency). So from a climate change point of view, natgas is better.
2. coal vs natgas. thermal coal use in US peaked because it was displaced by natural gas, whose price collapsed due to peculiarities of the US natgas market. Cheap gas accelerated the decommissioning of coal electric in the US just as much as environmental conscientiousness. Had natgas cost more, it may have made sense to make the investment in clean(er) coal. Where worldwide natgas prices will go is kind-of a mystery, and will have a direct affect coal use.
3. fuel choices for electric generation are all about the cost of transporting the fuel, more so than production. Extracting low-grade coal by surface-mining is a lot less than transporting it across a continent by rail. So the relative cost of rail networks vs pipelines may matter more than the relative cost of scooping up coal vs drilling for gas. Not sure how this plays out in developing countries.
4. In the case of renewables (solar etc), the big unknown is power transmission. I’m hoping for / expecting radical improvement in electric power transmission (graphene??) and high-power switching (the transistor age is still chugging along). Solar will drive this, but if it happens early enough, it could change the economics of fossil fuel choices as well??
Pete,
I agree with most of this. The Coal vs. natural gas comparison is today, but coal is likely going away due to environmental considerations — no matter what nat gas does. Also, nat gas prices are not low due to “perculiarities” but a supply increase faster than development of new uses (e.g. fleet vehicle use of nat gas, which is now far cheaper than gasoline).
“fuel choices for electric generation are all about the cost of transporting the fuel, more so than production.”
I don’t know what that means. Transportation cost of nuke fuel is insignificant, ditto geothermal, solar and wind. Transport cost varies greatly for coal and nat gas in grid production, as both are largley dependent on fixed transport systems (e.g., pipeline, water, rail).
For solar & wind distributed production is often feasible, meaning minimal cost of moving the electricity (albeit at the cost of greater complexity for the grid, but problem of backup power for these interruptible sources).
Regarding US market peculiarities … besides the supply boom, the US natgas market, unlike oil, has been largely disconnected from world pricing for the last 5 years at least. This was as the US transitioned from being a net importer to a potential net exporter, but for the time being lacking the facilities to export substantial amounts of natural gas by ship.
Regarding transport… yes, for nuclear it is not an issue at all, I forgot about that. But other non-carbon-fueled electricity, the electric production is usually located in the same region as the renewable resource (sunlight, wind, waterfalls). Seems to me that will have to change.
Pete,
Yes, U.S. has been an importer of nat gas and so doesn’t have big export facilities. I hadn’t considered this a “market peculiarity”, but that’s a matter of language. As you said — many forms of energy can be moved only thru extensive infrastructure. Other examples are coal and hydro.
Color me skeptical that electricity from solar and wind will ever be shipped long distances. Just modifying the grid to handle high percentages (>10%) of solar and wind will be difficult and expensive. Time will tell.
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This article has been around for a while – the original was in July, and then a run at WUWT (under the restrained headline “Manufacturing nightmares: an example of misusing climate science”). But it never had a point.
GCM’s are programs that will tell you the consequences of putting GHG’s in the atmosphere. They don’t tell you whether that will happen. To use them, you need a scenario of what you think might happen to GHGs. The CMIP programs are big cooperative efforts whereby people across the wold work for several years to analyse a common set of scenarios. The commonality is needed to make comparisons. Someone needs to choose scenarios that span the range of likely views. That range shouldn’t reflect any particular person’s view. It’s a way of rationally organising a huge effort so that it will be maximally useful.
So they chose a range, expressed by the numbers 2.6, 4.5, 6.5 and 8.5. The numbers, and the associated sequences of gas concentrations, are what are actually used. They are what matters. In choosing them, people explain why they think they are appropriate. Estimates of population growth etc. But different people will have different ideas on RCP8.5 as a top end. Some will think it’s right for certain reasons – some will think it is too high to be plausible – others will think more extreme scenarios are likely.
In practice, those rationales don’t matter. What counts for the program are the actual forcing numbers. And what counts for the designers is not the strength of their own rationale, but whether their numbers fit as yet unknown expectations of other people.
So the complaint here should not be directed at the program. What do you think is the right top end? Instead, it only makes sense as a criticism of what certain people believe about the future. But there it is hopelessly weak on evidence. Who are these people? What do they actually say? Why is what they actually say, wrong?
As usual for Nick Stokes, his rebuttal is a combination of factual errors and chaff. It’s a fun mode of analysis: just ignore what the article says and declare that there is no point. But the rest of your comment is even odded.
(1) “This article has been around for a while … then a run at WUWT … “Manufacturing nightmares: an example of misusing climate science”).”
Wrong again. That post at WUWT was a follow-up to this one. It showed the history of how RCP became described as the “business as usual” scenario, examples of how it was misused as such in the climate science literature and the general media.
(2) “What counts for the program are the actual forcing numbers.”
Wow. That is missing the point. What counts for the users of these forecasts is the likelihood of the assumptions (and the resulting forecast). Hence the great emphasis put by the authors of studies and articles that these are “business as usual” forecasts. They would have far less impact on climate scientists, policy decision-makers, journalists, and the public if described as forecasts using worst-case scenarios.
(3) “And what counts for the designers is not the strength of their own rationale, but whether their numbers fit as yet unknown expectations of other people.”
Is that from Zen and the Art of Climate Science? It’s bizarre in this context. Chaff to confuse people.
(4) “What do you think is the right top end?”
That’s not the relevant question, which is what is an accurate “business as usual” scenario.
(5) “What do they actually say?”
That’s why people put links in the text. Click on the relevant link above and you will go here, which answers your question:
http://fabiusmaximus.com/2015/11/05/visions-of-dark-climate-future-90153/
(6) “Why is what they actually say, wrong?”
This is an 1800 word essay explaining exactly that. As so often the case, your comments suggest that you have not read the text — just the title and summary, from which you write free-form verse intended to confuse people.
Apologies – the above comment was intended for the thread at Climate Etc.
Update about peaking of China’s coal production
“China coal consumption drops again“, The Guardian.
“Statistics From China Say Coal Consumption Continues to Drop“, The New York Times.
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